Drawing blood with vacuum tubes

Evaluation of di-potassium and tri-potassium EDTA evacuated tubes for routine haematological testing

BACKGROUND

The influence of blood collection devices on laboratory tests is often overlooked. We have discussed here how blood collection materials and devices can alter haematological test results, with an emphasis on blood collection tube (BCT) additives. We have compared K2 & K3-EDTA vacuum tubes of same manufacturer IMPROVACUTER ^® for CBC analysis.

METHODS

Blood was collected in both tubes simultaneously. Samples were analysed immediately after collection (<15 minutes) and after 4 hours by MEK-6318J/K Haematology Analyzer. Paired student's t-test was applied for statistical analysis. Significant differences among results and biases were compared with current quality specifications.

RESULTS

Significant differences were found in Neutrophyls (GR) and mean platelets volume (MPV) when compared. K2-EDTA vs K3-EDTA(1st time) after< 15 minutes of sample collection, for Monocytes counts (MO), MCV, MPV, and RDW when comparing K2-EDTA (first time) vs K2-EDTA(second time, after 4 hours); and for Monocytes counts (MO), MCV, MPV, PCT, and RDW when comparing K3-EDTA(1st time) vs K3-EDTA(2nd time) in order to check the stability and reproducibility of vacutainers.

CONCLUSIONS

This study assesses the use of K2& K3-EDTA vacuum tubes whether or not they represent a bias in haematological testing (CBC). The use of K2-EDTA and K3-EDTA vacuum tubes represent a clinically relevant source of variation for MCV, MPV, RDW, and PCT.

Impact of the phlebotomy training based on CLSI/NCCLS H03-a6 - procedures for the collection of diagnostic blood specimens by venipuncture

Introduction:

The activities involving phlebotomy, a critical task for obtaining diagnostic blood samples, are poorly studied as regards the major sources of errors and the procedures related to laboratory quality control. The aim of this study was to verify the compliance with CLSI documents of clinical laboratories from South America and to assess whether teaching phlebotomists to follow the exact procedure for blood collection by venipuncture from CLSI/NCCLS H03-A6 - Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture might improve the quality of the process.

Materials and methods:

A survey was sent by mail to 3674 laboratories from South America to verify the use of CLSI documents. Thirty skilled phlebotomists were trained with the CLSI H03-A6 document to perform venipuncture procedures for a period of 20 consecutive working days. The overall performances of the phlebotomists were further compared before and after the training program.

Results:

2622 from 2781 laboratories that did answer our survey used CLSI documents to standardize their procedures and process. The phlebotomists’ training for 20 days before our evaluation completely eliminated non-conformity procedures for: i) incorrect friction of the forearm, during the cleaning of the venipuncture site to ease vein location; ii) incorrect sequence of vacuum tubes collection; and iii) inadequate mixing of the blood in primary vacuum tubes containing anticoagulants or clot activators. Unfortunately the CLSI H03-A6 document does not caution against both unsuitable tourniquet application time (i.e., for more than one minute) and inappropriate request to clench the fist repeatedly. These inadequate procedures were observed for all phlebotomists.

Conclusion:

We showed that strict observance of the CLSI H03-A6 document can remarkably improve quality, although the various steps for collecting diagnostic blood specimens are not a gold standard, since they may still permit errors. Tourniquet application time and forearm clench should be verified by all quality laboratory managers in the services. Moreover, the procedure for collecting blood specimens should be revised to eliminate this source of laboratory variability and safeguard the quality.

K(3)EDTA Vacuum Tubes Validation for Routine Hematological Testing

Background and Objective. Some in vitro diagnostic devices (e.g, blood collection vacuum tubes and syringes for blood analyses) are not validated before the quality laboratory managers decide to start using or to change the brand. Frequently, the laboratory or hospital managers select the vacuum tubes for blood collection based on cost considerations or on relevance of a brand. The aim of this study was to validate two dry K(3)EDTA vacuum tubes of different brands for routine hematological testing. Methods. Blood specimens from 100 volunteers in two different K(3)EDTA vacuum tubes were collected by a single, expert phlebotomist. The routine hematological testing was done on Advia 2120i hematology system. The significance of the differences between samples was assessed by paired Student's t-test after checking for normality. The level of statistical significance was set at P < 0.05. Results and Conclusions. Different brand's tubes evaluated can represent a clinically relevant source of variations only on mean platelet volume (MPV) and platelet distribution width (PDW). Basically, our validation will permit the laboratory or hospital managers to select the brand's vacuum tubes validated according to him/her technical or economical reasons for routine hematological tests.