Printed from acutecaretesting.org
Journal Scan
April 2017
Phlebotomy recommendation reiterated
Summarized from Cornes M, van Dongen-Lases E, Grankvist K et al. Order of blood draw: opinion paper by the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) working group for the preanalytical phase (WGPRE). Clin Chem Lab Med 2017; 55: 27-31
It is widely acknowledged that the majority of errors in clinical laboratory and point-of-care testing occur during the preanalytical phase.
Blood collection (phlebotomy) is an element of the preanalytical phase particularly prone to potential error, so that adherence to authoritative (evidence-based) recommendations on phlebotomy technique is essential to the integrity of patient test results.
National, international and local phlebotomy guidelines contain the advice that blood should be transferred to sample tubes in a precise order to prevent contamination of blood samples with additives present in some blood collection tubes. This recommendation was first made over 20 years ago on the basis of the evidence then available.
An expert working group of the European Federation for Clinical Chemistry and Laboratory Medicine (EFCCLM) sought to revisit the evidence base for the “order of blood draw” recommendation in the light of study conducted since it was first proposed. Their deliberations and conclusion are revealed in this recently published paper.
It is unclear how the literature search was conducted, but the authors reviewed 14 relevant papers published since 2008. A small minority is single-case study reports of exogenous sample contamination, but most are studies aimed at assessing the potential for exogenous contamination if sample draw order recommendations are not observed.
These are predominantly concerned with the potential for K-EDTA contamination of samples destined for potassium/calcium measurement.
The authors conclude that the evidence suggests that if a closed-loop system of blood collection is used in accordance with manufacturer’s instructions, then contamination does not occur and the order of draw is “seemingly not important”.
Notwithstanding this, and with evidence that the recommended closed-loop system is not always used, the authors find there remains an evidential risk of erroneous results if the recommended order of draw is not observed.
The working group therefore concludes that the order of draw recommendations should continue to always be followed. The recommended order of draw is:
1. Blood culture tube
2. Coagulation tube
3. Serum tube, with or without clot activators, with or without gel
4. Heparin tubes, with or without gel
5. EDTA tubes
6. Glycolytic inhibitor tubes
7. Other tubes (e.g. trace elements)
Blood collection (phlebotomy) is an element of the preanalytical phase particularly prone to potential error, so that adherence to authoritative (evidence-based) recommendations on phlebotomy technique is essential to the integrity of patient test results.
National, international and local phlebotomy guidelines contain the advice that blood should be transferred to sample tubes in a precise order to prevent contamination of blood samples with additives present in some blood collection tubes. This recommendation was first made over 20 years ago on the basis of the evidence then available.
An expert working group of the European Federation for Clinical Chemistry and Laboratory Medicine (EFCCLM) sought to revisit the evidence base for the “order of blood draw” recommendation in the light of study conducted since it was first proposed. Their deliberations and conclusion are revealed in this recently published paper.
It is unclear how the literature search was conducted, but the authors reviewed 14 relevant papers published since 2008. A small minority is single-case study reports of exogenous sample contamination, but most are studies aimed at assessing the potential for exogenous contamination if sample draw order recommendations are not observed.
These are predominantly concerned with the potential for K-EDTA contamination of samples destined for potassium/calcium measurement.
The authors conclude that the evidence suggests that if a closed-loop system of blood collection is used in accordance with manufacturer’s instructions, then contamination does not occur and the order of draw is “seemingly not important”.
Notwithstanding this, and with evidence that the recommended closed-loop system is not always used, the authors find there remains an evidential risk of erroneous results if the recommended order of draw is not observed.
The working group therefore concludes that the order of draw recommendations should continue to always be followed. The recommended order of draw is:
1. Blood culture tube
2. Coagulation tube
3. Serum tube, with or without clot activators, with or without gel
4. Heparin tubes, with or without gel
5. EDTA tubes
6. Glycolytic inhibitor tubes
7. Other tubes (e.g. trace elements)
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