Evacuated blood-collection tubes for haematological tests - a quality evaluation prior to their intended use for...

An inappropriate anticoagulant concentration in a blood sample can cause cell shrinkage and affect the haematocrit and mean corpuscular volume (MCV). In evacuated blood-collection tubes there are two parameters affecting the quality of the product: the anticoagulant amount introduced into the tube during its production and the internal under-pressure at the instant of the blood-specimen collection affecting the draw-volume. No testing procedures that would give an insight into the anticoagulant concentration that can be expected for blood samples after specimen collection have been available up until now.

The methodology suggested here combines the draw-volume test performed with deionised water using a laboratory made measuring device, and a conductivity measurement. The corrections taking into account the air pressure and ambient temperature provide an insight into the anticoagulant concentration that can be expected for blood samples. Results presented in the form of a nomogram facilitate the routine use of the suggested methodology.

Our 338-day study confirmed significant differences and variations in the quality and the anticoagulant concentrations of the K₃EDTA and K2EDTA tubes of different producers and identified different examples of non-compliance with the norms during the shelf life of the tubes.

The quality evaluation of the evacuated blood-collection tubes prior to their intended use as suggested here can, in everyday laboratory practice, ensure that the tubes are used only if, and only until, their quality is adequate.