Supplementary Notes from DFK Haematology Desk

Following tradition, on the quote on CLSI guideline, I meant that is particularly of more importance for K3 EDTA.

If institutions ARE SO USED to the liquid K3 EDTA blood collection tubes, then there is no compromise on the fact that the sample volume must not be more than 10% less than the stated volume on the specimen container as prescribed by the local (MLSCN) and international regulatory bodies (CLSI, ICSH on quality laboratory practice.

What that means is this: If
5 mL is stated on K3 EDTA or other specimen bottle (apart from the spray-dried K2 EDTA being discussed), 4.5 mL is d minimum sample volume; if 4 mL , 3.6 mL is d minimum & if 2 mL, 1.8 mL is the minimum specimen volume.

The calculations? 10% of 5 mL is 0.5 mL Deduct that from the stated volume. You have
4.5 mL. That means, the volume of sample collected into that specimen bottle where the manufacturer stated 5 mL must not be less than 4.5 mL. For quality laboratory results.

Imagine a scenario where a particular professional is on call/ at work during working hours, and collected the appropriate specimen volume for pre- transfusion or pre-delivery procedure and got a result. Another colleague took over and post-delivery/post-transfusion PCV sample was received with some compromise on specimen volume in K3 EDTA container (Let’s say 2.0 or 2.5 mL instead of 5 mL as we used to see), BE VERY CERTAIN POST- TRANSFUSION PCV WILL BE LESS THAN PRE-TRANSFUSION PCV. Post-delivery PCV will be less than pre-delivery PCV especially where there is no evident blood loss.

These are reasons why haematologists say collect the appropriate sample volume CONSISTENTLY for in-patients and out-patients on follow up. It will be worse if the request is for routine complete blood count analysis.

We are discussing haematology here.

What to note in addition are these:

1. The insistence is more vital for specimens meant for QUANTITATIVE ANALYTICAL PROCEDURE.
2. For qualitative tests (e g. Hb. Genotype, HIV, HBsAg & anti-HCV screening, we may not be so strict though right volume is still d norm.
3. .For other haematological procedures, please follow the instructions on specimen requirements. The personnel on the specimen reception and registration table must be so trained and must have all the details on criteria for specimen acceptance and rejection for all haematological analyses..