Sampling with blood collection tubes
Collection and handling of capillary blood samples
Avoiding pre-analytical errors during collection and handling of capillary blood specimens in blood collection tubes
- Consult institutional guidelines for the volume of sample required for the test type and testing instrumentation
- Ensure each tube is filled to the correct volume of blood as indicated on the collection tube; over-filling or under-filling may lead to inaccurate results1
- Immediately cap specimen tube and mix contents1 by gently inverting several times*
to ensure sufficient mixing of blood with tube additive; this additive will promote clotting or prevent clotting as required by the specific test
- Do not shake the tube or mix vigorously as this may cause haemolysis1
- If collecting multiple tubes (following an order of sample collection),
cap and mix the sample after each tube is filled
- Correct mixing technique is vital as failure to mix sample with additive sufficiently may lead to specimen rejection and inaccurate test results1
To facilitate complete mixing of specimen with tube additive, swirl the tube gently after each drop of blood is collected into the tube
These materials have been produced in consultation with key opinion leaders and follow global guidelines, but the user should use his or her professional judgement when using any technique or method described in these materials and should take into account all applicable national, regional and institutional guidelines and regulations.
1. Clinical and Laboratory Standards Institute (CLSI) document GP42-A6 (former H04-A6): Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard – Sixth Edition. Clinical and Laboratory Standards Institute; Wayne, Pennsylvania, USA: 2008.
* The exact number of inversions may be determined by the tube manufacturer