Objectives: This study was aimed to investigate the influence of tourniquet application performed by two different groups involving expert and non-expert phlebotomists on the biochemical laboratory testing. Materials and Methods: Ten experienced and ten inexperienced phlebotomist responsible of venipuncture were included in the study. The effects of the tourniquet application time recorded for each group were evaluated for laboratory testing. Results: Tourniquet application time was found as 18.9 +/- 9.8 sec for experienced and 37.4 +/- 11.2 sec for inexperienced staff (p<0.001). Biochemistry and immunological tests including glucose, urea, creatinine, uric acid, cholesterol, triglyceride, total protein, albumin, bilirubins, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, amylase, creatine kinase, lactate dehydrogenase, alkaline phosphatase, Na, K, thyroid stimulating hormone, free thyroxin, estradiol, HCG performed with the blood obtained after 30 sec and 60 sec of tourniquet application time. None of these parameters showed any statistically significant differences and had lower analytical precision levels when compared to the values of Proficiency Testing Criteria for Acceptable Performance. Conclusion: According to the results, the acceptable period for tourniquet application might be recommended as 30-60 sec. Biochemical tests remained within the analytical precision limits when analyzed on blood drawn after venous stasis in determined periods. In conclusion, present study confirmed that tourniquet placing might affect biochemical and immunological tests minimally that could be neglected.

Tourniquet time for experts and nonexperts staff

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http://www.TurkJBiochem.com ISSN 1303–829X (electronic) 0250–4685 (printed) 85

Tourniquet Application Time During Phlebotomy and The

Influence on Clinical Chemistry Testing; Is It Negligible?

[Turnike Uygulama Süresi ve Klinik Kimya Testlerine Etkisi: İhmal Edilebilir

Mi?]

Research Article [Araştırma Makalesi]

Türk Biyokimya Dergisi [Turkish Journal of Biochemistry–Turk J Biochem] 2008; 33 (3) ; 85–88.

Muhittin A. Serdar1,

Levent Kenar2,

Adnan Haşimi1,

Levent Koçu1,

Yaşar H. Türkmen1,

İsmail Kurt1,

Şerif Akman1,

M.Kemal Erbil1

1 Department of Clinical Biochem istr y, Gulhane

School of Medicine, Etlik, Ankar a, Turkey.

2 Department of Clinical Biochem istr y and Medical

NBC Defense, Gulhane School of Medicine, Etlik,

Ankara, Turkey.

Yazışma Adresi

[Correspondence Address]

Muhittin A.SERDAR

Depar tment of Clinical Biochemistry, Gulhane

School of Medicine, 06018, Etlik, An kara, Turkey.

E-mail: maserd ar@gata.edu.tr

Tel : 0090 312 3043308

Fax : 0090 312 3043300

Kayıt tarihi: 15 Temmuz 2008, Kabul tarihi: 21 Temmuz 2008

[Received: 15 July 2008, Accepted: 21 July 2008]

Yayın tarihi 19 Eylül, 2008 © TurkJBiochem.com

[Published online 19 September, 20 08]

ABSTRACT

Objectives: This study was aimed to investigate the influence of tourniquet ap-

plication performed by two different groups involving expert and non-expert phle-

botomists on the biochemical laboratory testing.

Materials and Methods: Ten experienced and ten inexperienced phlebotomist re-

sponsible of venipuncture were included in the study. The effects of the tourniquet

application time recorded for each group were evaluated for laboratory testing.

Results: Tourniquet application time was found as 18.9 ± 9.8 sec for experienced

and 37.4 ± 11.2 sec for inexperienced staff (p<0.001). Biochemistry and immuno-

logical tests including glucose, urea, creatinine, uric acid, cholesterol, triglyceride,

total protein, albumin, bilirubins, alanine aminotransferase, aspartate aminotrans-

ferase, γ-glutamyl transpeptidase, amylase, creatine kinase, lactate dehydrogenase,

alkaline phosphatase, Na, K, thyroid stimulating hormone, free thyroxin, estradiol,

HCG performed with the blood obtained after 30 sec and 60 sec of tourniquet ap-

plication time. None of these parameters showed any statistically significant dif-

ferences and had lower analytical precision levels when compared to the values of

Proficiency Testing Criteria for Acceptable Performance.

Conclusion: According to the results, the acceptable period for tourniquet application

might be recommended as 30-60 sec. Biochemical tests remained within the analyti-

cal precision limits when analyzed on blood drawn after venous stasis in determined

periods. In conclusion, present study confirmed that tourniquet placing might affect

biochemical and immunological tests minimally that could be neglected.

Key Words: venipuncture, tourniquet time, laboratory test, analytical precision

ÖZET

Amaç: Bu çalışmada öncelikle uzman ve uzman olmayan flebotomistler için turni-

ke uygulama süresinin incelenmesi amaçlanmıştır.

Gereç ve Yöntem: Bu amaç için on uzman ve on deneyimsiz flebotomist çalışma-

ya alındı. Elde edilen turnike uygulama sürelerine göre de laboratuvar testlerine

etkileri araştırıldı.

Sonuçlar: Turnike uygulama zamanı uzman personel flebotomist için 18,9 ± 9.8

sn, deneyimsiz personel grubu için ise 37,4 ± 11.2 sn olarak tespit edildi (p<0.001).

30 ve 60 sn turnike uygulama süresiyle alınan kanlarda biyokimyasal ve immüno-

lojik testlerden glukoz, üre, kreatinin, urik asit, kolesterol, trigliserit, total protein,

albumin, bilirubinler, alanin aminotransferaz, aspartat aminotransferaz, γ-glutamil

transpeptidaz, amilaz, kreatin kinaz, laktat dehydrogenaz, alkalen fosfataz, Na, K,

tiroid uyarıcı hormon, serbest tiroksin, estradiol, HCG ölçümleri yapıldı. Bu test-

lerin hiçbirinde istatistiki değişim saptanmamıştır ve Kabul Edilebilirlik Perfor-

manslar İçin Yeterlilik Test Kriterlerine göre analitik tekrarlanabilirlik değerlerinin

düşük olduğu tespit edilmiştir.

Sonuçlar: Bu sonuçlara göre kabul edilebilir turnike uygulama süresi 30-60 sn ara-

sındadır. Bu uygulama süresinde biyokimyasal test sonuçları analitik tekrarlanabi-

lirlik sınırları içerisindedir. Sonuç olarak, bu çalışmada, turnike uygulamalarının

biyokimyasal sonuçları anlamlı düzeyde etkilemediği ve bu etkilenmenin ihmal

edilebilir seviyede olduğu değerlendirilmiştir.

Anahtar Kelimeler: Kan alımı, turnike zamanı, laboratuvar testleri, analitik tek-

rarlanabilirlik

Turk J Biochem, 2008; 33 (3) ; 85–88. Serdar et al. 86

Introduction

In the field of clinical biochemistry, laboratory errors

might originate from preanalytical, analytical and post

analytical sources. Preanalytical errors during collecti-

on of samples, specimen handling, storage and delivery

of the specimens, and analytical errors have been the

main targets to be minimized into the acceptable limit

of numbers (1,2,3).

The type and time of tourniquet application before the

blood is drawn has been one common source of preanal-

ytical errors. As reported by many authors, tourniquet

placement during venipuncture might provide alterati-

ons in the results of several traditional biochemical anal-

ytes due to the prolonged venous stasis (1,2,3). However,

time periods for tourniquet placement were given as 1, 3

or 6 minutes. The aim of this study was to assess the ef-

fect of different tourniquet application times on several

routine biochemical testing according to the experience

status of the staff performing phlebotomy (1,2).

Methods

Blood samples were drawn after written informed con-

sent was obtained from apparently healthy volunteers

(60 women, 60 men; mean age 45.4 ± 12.45 years) by

phlebotomists using a butterfly needle connected to an

evacuated tube holder. Serum was obtained after clot-

ting for 30 min at room temperature, followed by cen-

trifugation at 2000 x g for 5 min. All specimens were

processed within 2 h of collection.

Venipunctures were done on different veins of antecubi-

tal site to exclude any interference originating from the

previous tourniquet. The first phlebotomy was carried

out without any tourniquet application, whereas the se-

cond and third venipunctures were performed on 30 sec-

stasis and 60 sec-stasis by 6 experienced phlebotomist

and other 6 non-expert blood-drawing staff. Here, expe-

rienced staff was nominated as those who were assigned

for venipuncture for three years, and non-experts were

medical and nursing students on phlebotomy training.

The blood samples were drawn with 21-gauge straight

needle. All blood collection procedure was completed

within 10 minutes from the first draw. Blood samples

were centrifuged at 3000 x g for 10 minutes for serum

separation, stored in aliquots and kept at -70 ºC until as-

say.

Routine biochemical tests including the measurement of

glucose, urea, creatinine, uric acid, cholesterol, triglyce-

ride, total protein, albumin, conjugated / unconjugated

bilirubin, alanine aminotransferase (ALT), aspartate

aminotransferase (AST), gamma-glutamyl transpeptida-

se (GGT), amylase, creatine kinase (CK), lactate dehyd-

rogenase (LDH), alkaline phosphatase (ALP), sodium

(Na), potassium (K) were performed on AU 2400 au-

toanalyzer (Olympus, Japan) by using the commercially

available kits. The levels of thyroid stimulating hormone

(TSH), thyroxine, estradiol and HCG were measured on

Roche E-170 modular immunoanalyzer (Roche Diag-

nostica, Germany) by using electrochemiluminescence

technique. The instrument was calibrated against app-

ropriate reference standard material and controlled daily

by the use of control sera. All measurements were per-

formed in triplicate.

All results were compared with average CV and Health

Care Financing Administration/Clinical Improvement

Amendments (HCFA/CLIA) Proficiency Testing Crite-

ria for Acceptable Performance. Avarage coefficients

of variation [(intraassay CV % + interassay CV %) /2)]

were calculated by the measurements of control sera

with two different concentrations for seven times in a

day and in different days (4).

Statistical analyses were performed by using SPSS

15.0 for Windows. Significance of differences between

samples was evaluated by Wilcoxon and Mann Whitney

U test and p<0.05 was accepted as the level of statistical

significant changes.

Results

When the time of tourniquet use by non-experts and

experts were compared, the duration of venous-statis

during the phlebotomy by experienced staff was found

statistically shorter (p<0.001). Experts' time of use was

18.9 ± 9.8 sec, whereas non-experts' time was 37.4 ± 11.2

sec (Figure 1). Tourniquet time lasted more than one mi-

nute in 3 samples (5 %), however, this time was recorded

below 30 sec when performed 52 times by experienced

phlebotomist (87 %) and 23 by non-experts (38 %). The-

se results showed that time of tourniquet application by

phlebotomists were less than 30 sec in routine use.

Table 1 and Figure 2 illustrate the changes in routine

biochemical test results affected by tourniquet applica-

tion for 30 sec, 60 sec and average CV %. In this regard,

no statistical difference was found between the results

obtained in the specimens drawn following a tourniquet

application for 30 sec and 60 sec. Additionally, all tour-

niquet applications gave no different results in parame-

ters when compared those obtained at tourniquet applied

for the time of intraassay CV %. The results found were

lower than the values of intraindividual CV % (Table 1

and Figure 1). Thus, these results were lower than that

found as analytical error and those found in levels in

HCFA/CLIA Proficiency Testing Criteria for Acceptab-

le Performance Criteria.

Discussion

The development in laboratory automation technology

and quality control performance of the testing process

has improved the errors in analytical phase and caused

the laboratory staff to be more interested and alerted on

preanalytical errors within laboratory testing process (1,

2). So, overall prevalence of analytical error has been re-

duced as the improvement in laboratory automation has

been accelerated.

Turk J Biochem, 2008; 33 (3) ; 85–88. Serdar et al. 87

As the duration of tourniquet placement extends, the ef-

fect of increased intravenous pressure and hypoxia on

vascular endothelium triggers the infiltration of small

molecules and fluid from lumen to the peripheral tis-

sues. Proteins (involving lipoproteins), erythrocytes and

other blood cells cannot pass through the membrane at

the same rate. Therefore, their concentrations in plasma

will increase. However, the relative levels of proteins

like immunoglobulins will also increase in sera. In ad-

dition, proteins and protein-bound substances in plasma

are also largely influenced by venous stasis leading to

an increase in protein-bound calcium levels. Thus, for

calcium analysis, blood should be drawn without tour-

niquet placement if any increase was noted previously.

In a similar manner, protein-bound hormone measure-

ments are also under effect of stasis time. Hypoxia due

to the elongated stasis may also cause intracellular ele-

ments to infiltrate into the plasma (1,5).

Figure 1. Tourniquet time for experts and nonexperts staff

Table 1. Comparison of mean values of alterations on test results run after 30 sec and 60 sec tourniquet application with the values of intrain-

dividual CV %, interassay CV % and HCFA/CLIA.

Alteration (%) interassay

CV %

Intraindividual

CV %

HCFA/

CLIA

30 sec 60 sec

Glucose -2.3 -2.2 3.9 10 8.3

Urea 1.1 0.1 2.1 9 18

Creatinine -1.8 -1.2 2.5 15 6.8

Uric acid -2.8 -2.9 3.1 17 9

T. Cholesterol 0.1 -2.3 2.5 10 8. 2

Triglyceride -2.1 0.1 2.6 25 28.8

Bilirubin (conj.) -4.8 -5.2 4.2 20 24.6

Bilirubin (unconj.) 2.2 4.1 4.6 20

AST 3.1 3.3 3.4 20 15.1

ALT 2.1 -1.0 3 .3 20 23.7

ALP -0.9 -1.2 3.4 30 4.4

Total Protein -0.7 -2.1 2.6 10 3.5

Albumin - 0.8 -0.9 2.5 10 2.8

LDH -1.2 -4.3 3.7 20 7.9

CK 1.0 -1.2 3.6 30 2 2.8

Sodium 0.1 -1.1 1.9 5 1.6

Potassium 3.1 1.9 2.3 5 5.4

Calcium - 0.8 -2.1 2.1 10 3.3

TSH 2.1 3.1 3.4 2 0 24

Thyroxine 1.3 2.4 2.8 20 25

Estradiol -1.4 -1.9 2.4 20

HCG -2.5 3 3.6 20

Turk J Biochem, 2008; 33 (3) ; 85–88. Serdar et al. 88

A suitable blood-drawing technique requires a

fulfillment of rigorous and standardized criteria. The

time for tourniquet application differs from patient to

patient. For instance, venous stasis time may be longer

for obese patients whose veins are not easily visible for

blood drawing. In this study, the applications time was

less than one minute even for non-expert staff. Even in

cases with 60 sec-tourniquet application, changes were

found lower than intraassay variation values for some bi-

ochemical tests reported in previous studies. The reason

might be the longer duration of tourniquet placement

(for 3 min or 6 min).

It was reported that levels of some biochemical tests inc-

luding total protein, iron, cholesterol, AST and bilirubin

were found to be increased due to the venous stasis, es-

pecially potassium levels were changed in the range of

4.9-9.3 % (5).

In another study, Lippi et al. assessed the changes at le-

vels of 12 testing parameters after a tourniquet place-

ment for 1-3 min and found significant changes in ALT,

albumin, potassium, iron, glucose, creatinine kinase

where a sphygmomanometer was used for venous stasis

(6). Our study aimed to find out the effect of tourniquet

time on the change of biochemical tests and to evaluate

this effect on the analytical precision of test parameters

under conditions of routine venipuncture application

showed no variation in the test results . The changes in

biochemical tests were found lower than the values for

intraindividual % CV as noted in Table 1 and Figure 1,

and the effects on CLIA values were also minimal. Sin-

ce intraindividual values were lower and had no signi-

ficant differences when compared with intraassay CV

% values, it could be pointed out that tourniquet app-

lication performed up to 60 sec had no significant on

results. The main aspect of present study differing from

the other related studies was the determination of real

tourniquet application time and focusing on the changes

for the 30-60 sec application time.

However, we used tourniquet placement to provide a

real-life experience which was almost different than

previous studies, and that was the reason of the lower

incidence of venous stasis effect. Consequently, time for

tourniquet application was commonly found below than

30 sec. In addition to that, this performance time may

also be stated as less than one minute even for inexpe-

rienced phlebotomist and patients whose blood-drawing

is almost tedious, and this duration may not influence

the laboratory test results.

References

[1] Young DS, Bermes EW, Hoverstick DM. (2006) Specimen col-

lection and processing sources of biological variation In: Burtis

CA, Ashwood ER, Burns DE eds. Tietz Text Book of Clinical

Chemistry and Molecular Diagnosis, 41-58, 4th ed. Philadelphia,

Sounders Company.

[2] Guder WG, Narayanan S, Wisse H, Zawta B. (1996) Samples:

from the patient to the Laboratory. The impact of preanalytical

variables on the qualit y of laboratory results. Git Verlag GMBH,

Darmstadt.

[3] Lippi G, Salvagno GL, Brocco G, Guidi GC. (2005) Preanalyti -

cal variability in laboratory testing: inf luence of the blood draw-

ing technique. Clin Chem Lab Med. 43(3):319-25.

[4] Health Care Financing Administration/Clinical Improvement

Amendments Proficiency Testing Criteria for Acceptable Per-

formance: From the US Department of Health and Human Ser-

vices: Clinical Laboratory Improvement Amendments of 1998;

Final Rules and Notice.42 CFR Part 493. The Federal Register.

57:7188-288.

[5] Statland BE, Bokelund H, Winkel P. (1974) Effect of posture

and tour niquet application on variation of serum constituents in

healthy subjects. Clin Chem. 20:1513-19.

[6] Lippi G, Salvagno GL, Montagnana M, Brocco G, Guidi

GC.(2005) Inf luence of short-term venous stasis on clinical

chemistry testing. Clin Chem Lab Med. 43(8):869-75.

Figure 2. This gure illustrates the changes in values of biochemical parameters and total coefcients of variation (% CV) and individual

variation in all biochemical testing parameters depending on various application time (30 and 60 sec) indicated below.

... It has also been reported that most of these alterations occur to protein bound substances in plasma including calcium (Sedar et al., 2008). ...

... Our findings showed that prolonged tourniquet applica-tion has a direct significant effect on total cholesterol, and HDL-Cholesterol but not triglyceride and LDL cholesterol. In a similar study by Sedar et al, (2008) on the effect of tourniquet application, the duration of tourniquet application was compared between expert and non-expert phlebotomists. ...

... Their % mean differences were however found to be 7.4% and 1.5% respectively. This partly agrees with the work of Sedar et al, (2008) though tourniquet application was shorter and prolonged in their work and ours respectively. Also, the insignificant variation in the concentrations of triglyceride and LDL-cholesterol is consistent with earlier findings where blood sampling technique similar to what was employed in our study produced unaltered values for routine blood gases, hematological testing but not lipid parameters (Cengiz et al., 2009). ...

Background: The effect of prolonged tourniquet application on lipid profile parameters (total cholesterol, triglyceride, high density lipoprotein cholesterol (HDL-c) and low density lipoprotein cholesterol (LDL-c)) among healthy students in the University of Cape Coast was assessed in this study. Methods: A total of 30 participants were sampled and venous blood was taken from both arms at different duration of tourniquet application. Blood was allowed to clot, centrifuged and serum separated and stored until assay. Lipid profile parameters were measured using the enzymatic techniques with the aid of a spectrophotometer. Lipid parameters were expressed in mmol/L. The relationship between the concentrations was analyzed using GraphPad Prism version 6.0. Results: The mean serum levels of total cholesterol and HDL-c were significantly (p<0.05) elevated after long duration (13.44±2.40 s) of tourniquet application compared to short duration (11.20±0.38 s) of tourniquet application. Despite the fact that the serum levels of triglyceride and LDL-c increased after long duration of tourniquet application compared to short duration, the difference was not significant (p>0.05). There was significant % mean differences of 7.0% (p<0.0001) and 11.2% (p=0.0082) in the concentrations of total cholesterol and HDL-c respectively following prolonged tourniquet application of 120-180 s. A significant increase of up to 7% (5.01±0.04, 5.352±0.05, p<0.0001) and 11% (2.41±0.07, 2.674±0.07, p=0.0082) in the concentrations of total cholesterol and HDL-c respectively was also recorded. Conclusion: Prolonged venostasis has a direct effect on the concentration of serum total cholesterol and HDL-c but not triglyceride and LDL-c. Nonapplication of tourniquet in patients with prominent veins, the application of standardized external pressure as well the early release of tourniquet after needle insertion in the vein should be followed during sample taking for lipid profile. Annals of Medical Laboratory Science (2021) 1(1), 1 - 7

... It can lead to adverse problems in patient safety and healthy life if not properly regulated. Patient identification problem, usage of incorrect blood collection equipment and improper skin puncturing practices are most problems occurred during phlebotomy service and also laboratory results can be affected during tourniquet application, improper usage of disinfectants [11], improperly using of Vacutainer tube sequence during collection and improper patient identification and instruction before collection [12]. ...

... We observed more than 80% of phlebotomists were found wrongly applying the tourniquets. Literatures indicated prolonged tourniquet application will increase the hemoconcentrations of non filterable [1,4,10,12,14,17,18]. For that reason in our study time of applying of tourniquets includes with in recommended time (51.6±12.5). ...

... For that reason in our study time of applying of tourniquets includes with in recommended time (51.6±12.5). However, this result was different with the study showed by Serdar et al as average time of less than 30 seconds [12]; but, our finding disproof the finding of Lina-Oliver G, et al that the overall mean (SD) application time of 84.4± 14.1 [4]. ...

  • Abay Sisay Misganaw Abay Sisay Misganaw

Background : Phlebotomy is the system of drawing a blood sample for the use of laboratory testing and for blood transfusion. Professionals who are performing phlebotomy services called phlebotomists. It is a critical part of the pre analytical phase of laboratory testing and is the most neglected procedures in health care. About 70% of the quality of the test are affected during phlebotomy and other pre analytical services. However, little is known about the practice of phlebotomy services in developing countries like Ethiopia. Objectives : To assess the practice of phlebotomists and to identify the major sources of errors during venous blood collection in public hospitals in Addis Ababa. Methodology : Hospital based, cross sectional observational and follow-up study was conducted from March to May 30, 2014. The study followed 40 phlebotomists while each of them was collecting 5 different venous blood collections (giving a total of 200 phlebotomies). Well structured questionnaires and checklists were used to collect data. Data was entered on EPI-Data version 3.1 and statistical analysis was performed with SPSS version 20. Descriptive statistics were employed and the Chi square test was used for comparing major errors observed. Result : Almost all laboratory phlebotomy sites had no Standard Oprating Procedures (SOPs) available in collection sites and most of collection sites were not well ventilated. The major errors identified were use of single glove for more than one client 139 of 200 (69.5%), inappropriate cleaning practice of vein puncture sites 180 of 200 (90%), collecting blood before the disinfectant alcohol dried 139 of 200 (69.5%), incorrect tube collection sequences 107 of 200 (53.5%), unnecessarily applying of tourniquets after blood started flowing in to the collection tubes and syringes 170 of 200 (85.0%) and applying tourniquets before locating and selecting appropriate site for venous blood collection 175 of 200 (87.5%). Conclusion and Recommendation : -Many errors were identified in the phlebotomy practice during the observational study. As the quality of blood specimen influences patient result: emphasis should be given on phlebotomy training to improve the practices for phlebotomists and ensure safety as well as quality during blood collections for laboratory analysis. Keywords: Phlebotomy, Venous Blood Collection, Quality, Tourniquet, Preanalytical Errors

... Nevertheless, the final logistic regression model included only tourniquet time (P <0.001), with an increased risk of hemolysis corresponding to increased tourniquet time (the odds ratio for hemolysis when the tourniquet time exceed 1 minute was 19.5; 95% CI 5.6-67.4%). Different results were instead reported by Serdar et al., who, although not measuring the content of free hemoglobin in the samples directly, could observe only modest variations in the indirect markers of hemolysis (e.g., 1.9% for potassium, 4.3% for LDH, and 3.3% for AST, respectively) as a function of tourniquet placemrnt (up to 60 seconds) [54]. Although the reasons for hemolysis during prolonged venous stasis are mostly unknown, it has been speculated that hemoconcentration and altered water balance in the cells might occur, thereby causing lysis of RBCs and platelets. ...

Hemolysis is an important phenomenon in laboratory medicine because it may derive from two different sources, which deserve different approaches: (a) in vivo hemolysis, which may be caused by a variety of conditions and disorders, can lead to various degrees of anemia (up to life-threatening anemia, when the concentration of hemoglobin declines very rapidly and/or falls below 6 mg/dL), and (b) in vitro hemolysis, which is caused by inappropriate procedures for collection and/or handling of the biological specimen, and can seriously impact patient care and a laboratory's reputation through a wide range of adverse affects on test results. Hemolytic specimens are a frequent event in laboratory practice, with an average prevalence described as about 3% of all of routine samples referred to a clinical laboratory, and accounting also for 39–69% of all the unsuitable specimens received in clinical laboratories (i.e., nearly five times higher than the second major cause). Hemolysis, therefore, still represents the most prevalent preanalytical error across countries, health care facilities, and types of clinical laboratories. Several causes have been traditionally associated with an increased burden of in vitro hemolysis, including difficult venipunctures, use of inappropriate devices, underfilling of blood tubes, exposure to extreme temperatures and physical forces during sample transportation via pneumatic systems, and centrifugation at a too high speed of partially coagulated specimens. In addition, even an excessive shaking or mixing of blood after collection (i.e., for times longer than recommended or with great force) is also usually acknowledged as a leading source of RBC injury. The prevalence of hemolytic specimens is increasingly considered a reliable index for assessing preanalytical quality and, more interestingly, for introducing new tools and guidelines for the safe management of hemolytic samples. Therefore, this volume represents a fundamental source for updating knowledge on hemolysis and on a valuable approach to hemolytic samples in clinical practice.

... In standard phlebotomy practice, tourniquet up-times are usually less than a minute, and the World Health Organization indicates a tourniquet up-time of two minutes or less is best practice. 16,17 We did not record tourniquet up-time, but suspect that, since the study lactate was always the last blood drawn (so as not to interfere with necessary studies for patient management), study values represent lactates taken at the upper limit of tourniquet time. In a prior study of healthy volunteers, even 15 minutes of tourniquet up-time with a phlebotomy tourniquet did not alter lactate levels. ...

Objective Lactate levels are increasingly used to guide resuscitation efforts. Some surgical literature suggests that tourniquet use during phlebotomy falsely elevates results, although studies in healthy volunteers have not demonstrated this. The purpose of this study was to determine in clinical practice whether tourniquet use during the drawing of a lactate results in significantly altered levels compared to the result of a level drawn without a tourniquet. Methods A prospective cohort study was carried out on emergency department patients whose clinical presentation led a physician to order a lactate level. Written informed consent was obtained from patients or their proxies. Study lactates were obtained using a tourniquet during the draw sequence of other laboratory studies. Lactate levels for clinical use were drawn per hospital protocol with no tourniquet. The time of lactate measurements and patient demographic information were recorded. Lactate levels for each patient were compared with the Wilcoxon Rank-Sum Test. Results 40 patients were consented and enrolled. The median clinical lactate level was 1.9 (interquartile range 1.5-2.6), and the median study lactate level was 1.9 (interquartile range 1.4-2.7). There was no difference between paired lactate values ( p =0.95). Conclusions Tourniquet use appears to have no impact on measured lactate levels. Our findings suggest that current practices at many institutions regarding lactate collection are likely too stringent and should be changed.

... Tourniquet application time was reported as the time of tourniquet application by phlebotomists, which was < 30 s in routine use. Serdar et al. compared the duration of venous stasis during the phlebotomy between non-experts and experts; tourniquet application time of experienced staff was found to be statistically shorter [7]. ...

... Moreover, it brings the pH of the blood to be lower as a result of tissue hypoxia which in turn affects many laboratory parameters [27]. However, if tourniquet is not applied for more than 60 seconds, the impact on values of almost all laboratory parameters can be neglected and is even below the tolerable amount random errors [28]. ...

Pre-analytical phase of overall laboratory testing system continues to be the major source of errors that affect patient safety and health care system. One of the activities in this phase is venous blood collection (VBC), the most common type of specimen drawn or sent to clinical laboratories for further analysis; and the source for a potentially numerous types of errors. In this study, we focused on determining and comparing desirability/undesirability of activities during VBC in Ethiopian hospitals among different groups of professionals. We conducted a cross-sectional comparative study in three government hospitals in South Ethiopia from February 2012 to September 2012. Randomly selected professionals who participate in VBC in outpatient and inpatient departments were requested to fill in structured and pretested questionnaire regarding their practice of VBC and their replies were categorized as 'desirable' and 'undesirable' according to Clinical and Laboratory Standards Institute (CLSI) standard. Then, data was analyzed using Medcalc(R) version 12.1.4 software. P value of less than 0.05 was considered as statistically significant. In our study, 120 professionals were included among which 15.8% (n = 19) were laboratory professionals while the remaining 84.2% (n = 101) were non-laboratory professionals. Conscious patient identification in pre-collection phase of VBC and position of patients' hands in actual collection phase of VBC involved the highest proportion of undesirability among both groups of professionals. However, in the post collection phase, specimen transferring from syringes to test tubes (15.8%) and mixing specimen with additives (63.4%) involved highest proportions of undesirability among laboratory and non-laboratory professionals respectively. Laboratory professionals reported better desirable practice in patient identification frequency, labeling and checking expiry dates of test tubes, specimen transfer and transport practices. In conclusion, preparatory activities of VBC involved the highest proportions of undesirable practices among both groups of professionals. However, relatively better proportions of desirability were seen among laboratory professionals than non-laboratory professionals in some pre- and post-collection phase activities. The difference might be seen as a result of better qualification, education and training experience on VBC among laboratory professionals.

... The duration of venous occlusion (>1 min) can affect the sample composition. Prolonged occlusion may result in hemoconcentration and subsequently increase the miscellaneous analytes, e.g. total protein levels [Serdar MA, et al, 2008]. It is reported in the literature that levels of some biochemical tests including total protein, iron, cholesterol, and bilirubin were found to be increased due to the venous stasis (impairment or cessation of venous flow), especially potassium levels were changed in the range of 4.9-9.3 ...

Use of clinical laboratory test results in diagnostic deci¬sion making has become an integral part of clinical medicine. More than 60-70% of the most important decisions on admission, discharge, and medication are based on laboratory test results. With this high degree of influence, the reliability of laboratory testing and reporting is of utmost importance. Even though automation, standardization and technological advances have significantly improved the analytical reliability of laboratory tests, lab errors still do occur in the pre-analytical, analytical and post-analytical processes of the total testing process. It is the responsibility of the lab manager to minimize lab errors occurring at any stage of the testing process. Lab errors lead to sample rejection which in turn calls for repeat sample collection and analysis, and thereby cause delays in reporting the test results. Any delay in test results could have adverse consequences on the patients' health. Monitoring and control of lab errors is therefore an important challenge in the management of clinical labs so as to produce reliable test results as soon as possible and thereby achieve better lab performance.

  • Bastian
  • FD Anindita Marson
  • Asmarani
  • Pariyana

Potassium is an analyte that important because if there is a lack or too much potassium, it will causes someone is death, that is the reason why is the fault in measurement of potassium can make a serious condition to the patient if the therapy based on the laboratory result is not accurate. This study aims to know the effect of application technique of Tourniquet to potassium level. This study was a laboratory experimental that using serum from the subject. All of the data then processed statistically with paired T-Test. The result of the study was the mean of potassium level with Tourniquet application that released right after the vein can be accesed was about 3,86 mmol/L, lower than the second intervention that using Tourniquet application that not released until the volume of blood was enough, about 4,05 mmol/L. According to paired T Test result, p value is 0.003 with significancy 2 tailed (α=0.025) that makes p < α. This result show that there are differences of potassium level between two application technique of Tourniquet. ABSTRAK Kalium adalah analit yang penting karena jika ada kekurangan atau terlalu banyak kalium, itu akan menyebabkan kematian seseorang, itulah alasan mengapa kesalahan dalam pengukuran kalium dapat membuat kondisi serius bagi pasien jika terapi berdasarkan pada hasil laboratorium tidak akurat. Keadaan hemokonsentrasi sampel dapat mempengaruhi hasil akhir yang diperoleh. Penelitian ini bertujuan untuk mengetahui teknik aplikasi Tourniquet terhadap kadar kalium, dimana penggunaan Tourniquet yang kurang tepat juga dapat menyebabkan hemokonsentrasi sampel yang dapat meningkatkan kadar kalium dalam serum. Penelitian ini adalah eksperimental laboratorium yang menggunakan serum dari subjek. Semua data kemudian diolah secara statistik dengan T- Test berpasangan. Hasil penelitian adalah rata-rata kadar kalium dengan teknik Tourniquet yang dilepaskan tepat setelah vena dapat diakses adalah sekitar 3,86 mmol / L, lebih rendah dari intervensi kedua yang menggunakan aplikasi Tourniquet yang tidak dilepaskan sampai volume darah cukup, sekitar 4,05 mmol / L. Menurut hasil Uji T berpasangan, nilai p adalah 0,003 dengan signifikansi 2 tailed (α = 0,025) yang membuat p

The most common sources of error in the preanalytical phase are considered to be at the stage of patient preparation and sample collection. In order to reduce the preanalytical errors, we aimed to determine the level of phlebotomists knowledge about the preanalytic phase before and after planned trainings in the study. Training about preanalytical processes was given to the 454 health professionals and the majority of them were employed as nurse. Questionnaires before and after training were conducted. In order to assess the effect of the training into the process, preanalytical error rates were calculated before and after training. The total correct answer rates of vocational school of health diplomaed were statistically lower than the total correct answer rates of other. It was observed significantly increase in the rate of correct answers to questionnaire and significantly decrease in preanalytical error rates after training. The results of the survey showed that the attitudes of the phlebotomists were diverse in the preanalytical processes according to the levels of education and their practices. By providing training to all staff on a regular basis, their information about preanalytical phase could be updated and hence, it may possible to significantly reduce the preanalytical errors in health practice and nursing science.

Recent technical developments have focused on the full automation of urinalyses, however the manual microscopic analysis of urine sediment is considered the reference method. The aim of this study was to compare the performances of the LabUMat-UriSed and the H800-FUS100 with manual microscopy, and with each other. The urine sediments of 332 urine samples were examined by these two devices (LabUMat-UriSed, H800-FUS100) and manual microscopy. The reproducibility of the analyzers, UriSed and Fus100 (4.1-28.5% and 4.7-21.2%, respectively), was better than that with manual microscopy (8.5-33.3%). The UriSed was more sensitive for leukocytes (82%), while the Fus-100 was more sensitive for erythrocyte cell counting (73%). There were moderate correlations between manual microscopy and the two devices, UriSed and Fus100, for erythrocyte (r = 0.496 and 0.498, respectively) and leukocyte (r = 0.597 and 0.599, respectively) cell counting however the correlation between the two devices was much better for erythrocyte (r = 0.643) and for leukocyte (r = 0.767) cell counting. It can be concluded that these two devices showed similar performances. They were time-saving and standardized techniques, especially for reducing preanalytical errors such as the study time, centrifugation, and specimen volume for sedimentary analysis; however, the automated systems are still inadequate for classifying the cells that are present in pathological urine specimens.

  • B E Statland
  • Henning Bokelund
  • Per Winkel Per Winkel

The effects on 18 serum constituents of posture and prolonged tourniquet application were studied. The subjects were 11 healthy men, age 20-25 years. The assays were performed on the AutoChemist Multi Channel Analyzer. To compensate for the within hour variation in these constituents, the authors drew blood samples at 1100 hr and 1130 hr on several days. The 1100 hr sample was taken after the subjects had been sitting erect for 60 min. The 1130 hr sample followed different posture regimens: Control day: sitting for 15 min; experimental days: after being supine for 30 min, standing for 30 min and sitting erect for 30 min. The 1130 hr/1100 hr ratios for the three experimental days were compared with those for the control day. Significant differences (P<.05) were found for serum potassium, calcium, total protein, albumin, aspartate aminotransferase, and acid phosphatase under the first condition; for phosphate ion, total protein, total lipid, cholesterol, and alkaline phosphatase under the second condition; and for aspartate aminotransferase under the third condition. The effect of a 3 min tourniquet application was similarly studied. The ratio of the 'prolonged tourniquet application day' differed significantly from the control day with regard to serum potassium, total protein, iron, total lipid, cholesterol, aspartate aminotransferase, and bilirubin. Significance of posture and tourniquet time in blood sampling and their effect on total intraindividual variation are discussed. (18 references).

The predominant technique used to draw blood for laboratory testing is a conventional straight needle attached to an evacuated tube system. However, alternative tools might be advantageous in exceptional circumstances. The use of butterfly devices has been traditionally discouraged for reasons of costs and due to the high risk of obtaining unsuitable samples, but there is no convincing evidence to support the latter indication. The purpose of this study was to compare results of hematological and clinical chemistry testing, after drawing blood into evacuated tubes, employing either a traditional 21-gauge straight needle or a 21-gauge butterfly device with 300-mm-grade polyvinyl chloride tubing. Blood samples and complete sets of data were successfully obtained for 30 consecutive outpatients. Of the 43 hematological and clinical chemistry parameters measured, means for paired samples collected by the two alternative drawing techniques did not differ significantly, except for serum sodium, white blood cells and platelets counts. Bland-Altman plots and limits-of-agreement analysis showed mean bias of between -7.2% and 1.7% and relative coefficients of variation ranging from 0.2% to 21.2%. The 95% agreement interval in the set of differences was acceptable and was mostly within the current analytical quality specifications for desirable bias. The rate of hemolysis in plasma was not statistically different between the two collection techniques. Taken together, the results of the present investigation suggest that, when a proper technique is used and within certain limitations, the butterfly device may be a reliable alternative to the conventional straight needle to draw blood for laboratory testing.

Control and standardization of preanalytical variability is a critical factor for achieving accuracy and precision in laboratory testing. Although venous stasis from tourniquet placement during venepuncture should be minimized, as it has been claimed to account for spurious and significant variations for several analytes in plasma, there is controversy surrounding its real impact on laboratory testing. The aim of the present study was the investigation of the influence of short-term venous stasis on routine biochemical testing, by measuring the plasma concentration of 12 common analytes, including proteins, protein-bound substances, enzymes and electrolytes, in plasma specimens collected either without venous stasis or following the application of standardized external pressure of 60 mm Hg using a sphygmomanometer for 1 and 3 min. Although the overall correlation between measures was acceptable, the pattern of change was mostly dependent on the length of stasis, size and protein-binding characteristics of the analytes, achieving clinical significance for albumin, calcium and potassium after 1-min stasis, and alanine aminotransferase, albumin, calcium, chloride, total cholesterol, glucose and potassium after 3-min stasis. Statistically significant differences could be observed in seven (alanine aminotransferase, albumin, calcium, total cholesterol, creatine kinase, iron and potassium) and ten (alanine aminotransferase, albumin, calcium, chloride, total cholesterol, creatine kinase, creatinine, glucose, iron and potassium) out of the 12 analytes tested, after 1- and 3-min venous stasis, respectively. The most clinically significant changes from standard venepuncture, when compared to the current analytical quality specifications for desirable bias, occurred for potassium (1-min stasis, -2.8%; 3-min stasis, -4.8%, both p<0.001), calcium (1-min stasis, +1.6%, p<0.05; 3-min stasis, +3.6%, p<0.001) and albumin (1-min stasis, +3.5%; 3-min stasis, +8.6%, both p<0.001). As most of these effects are dependent on the stasis time during venepuncture and biochemical or physiological characteristics of the analyte, these variations could likely be anticipated, allowing the most appropriate preventive measures to be adopted.

Specimen collection and processing sources of biological variation

  • D S Young
  • E W Bermes
  • D M Hoverstick

Young DS, Bermes EW, Hoverstick DM. (2006) Specimen collection and processing sources of biological variation In: Burtis CA, Ashwood ER, Burns DE eds. Tietz Text Book of Clinical Chemistry and Molecular Diagnosis, 41-58, 4th ed. Philadelphia, Sounders Company.

Health Care Financing Administration/Clinical Improvement Amendments Proficiency Testing Criteria for Acceptable Performance: From the US Department of Health and Human Services

Health Care Financing Administration/Clinical Improvement Amendments Proficiency Testing Criteria for Acceptable Performance: From the US Department of Health and Human Services: Clinical Laboratory Improvement Amendments of 1998;