Effect of pre-analytical handling on haematological variables in minipigs

Pre-analytical handling may be an important determinant of haematological v ariables, if analysis is delayed. We investigated the effect of anticoagula nts, i.e. tripotassium ethylenediamine-tetraacetic acid (EDTA) and citric a cid, theophylline, adenosine, dipyridamole (CTAD), storage time (0.5, 1.5, 3.5, 5.5, 7.5, 25.5 and 27.5 h after blood sampling), and storage temperatu re (5 degreesC and 20 degreesC) on the variation in haemoglobin (HGB), red blood cell count (RBC), haematocrit (HCT), white blood cell count (WBC), an d platelet count (PLT) in minipigs. Medians of HGB, RBC, HCT, WBC and PLT w ere significantly higher in EDTA tubes than in CTAD tubes due to the diluti on effect of the anticoagulant. We found a minor significant increase in HC T after 25.5 h in blood stored at 20 degreesC, and at the same time a minor significant increase in WBC in EDTA tubes stored at 20 degreesC. We found a significant decrease in PLT in blood stored at 5 degreesC, especially in EDTA tubes. Minor variations were also observed in HGB and RBC. Our results indicate that PLT should only be measured in tubes placed at room temperat ure. If HCT or WBC analyses are to be performed on the day after blood samp ling, the samples must be stored in a refrigerator until analysis. Our stud ies underline that time delay before analysis of haematological variables c an cause increased variation, and should therefore be limited as far as pos sible in order to reduce the number of animals needed to make reliable conc lusions.