The integrity of a hematological sample is known to depend on time and temperature and the measurement technique has already been found to have an impact on stability.
Two specimen tubes containing an anticoagulant were tested for their affect on the stability of hematological parameters overtime. Full blood count and reticulocyte hematological analyses were conducted on a Beckman Coulter LH750 hematology analyzer (Beckman Coulter, Inc, Brea, CA, USA), at multiple time points up to 72 hours.
The two blood collection systems tested were the Vacutainer from Becton Dickinson, (BD; Franklin Lakes, NJ USA) and the Monovette from Sarstedt Inc., (Newton, NC, USA). In a recent study carried out by Icon Development Solutions (Manchester, UK), twenty healthy volunteers (10 males, 10 females) were recruited. No restrictions were placed on these volunteers. A total of 36.9 mL blood was taken from each volunteer, collected using a cannula into seven 2.7 mL ethylenediaminetetraacetic acid (EDTA) Sarstedt Monovettes and four 4.5 mL EDTA BD Vacutainers. Both types of tube are plastic and contain tri-potassium (K3) EDTA as an anticoagulant. Becton Dickinson tubes contain 7.2 mg K3 EDTA in a 4 mL tube; Sarstedt tubes contain sufficient K3 EDTA to achieve a concentration of 1.2-2 mg EDTA/mL blood, with a maximum dilution effect of 1%.
All parameters matched or exceeded Beckman Coulter stated stability values, with both Sarstedt and BD tubes showing remarkably similar levels of stability for all parameters. The exceptions were that mean platelet volume (MPV) was only stable for 18 hours in BD tubes and 24 hours in Sarstedt tubes, and neutrophils (NE) were stable for 72 hours in BD tubes, but only 48 hours in Sarstedt tubes. However, it was noted that the degradation of the Sarstedt samples appears to be more predictable and follows a much more linear pattern. Accurate full blood count results can be obtained on samples up to 48 hours, provided that the samples are stored in a refrigerator. The tube type was found to have minimal impact on the stability of hematological samples. The study was published in October 2010 in the British Journal of Biomedical Science.
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