Storage of blood samples at or above 33℃ leads to rapid appearance of appreciable systemic bias in platelet and mean corpuscular volume related parameters: an important pre-analytical factor in tropical conditions.

There is scant documentation of the stability of common haematological parameters on storage of blood samples under tropical conditions. K2EDTA samples in multiple vials were taken from 20 healthy blood donors, baseline readings taken, and stored at 33°C and 37°C. Readings from the stored vials were taken after 1, 3 and 6 h. The percent change against the baseline readings at each time point for each storage temperature was calculated. Platelet counts showed an unacceptable shift within 1 h at 37°C and 3 h at 33°C; red cell volume related parameters showed an unacceptable shift within 3 h at 37°C and 6 h at 33°C. Haemoglobin, red blood cell count, white blood cell count and mean corpuscular haemoglobin remained stable for 6 h at both temperatures. The unacceptable change for many parameters on storage at ≥33°C demonstrates the importance of ensuring pre-analytical control in regions experiencing such climatic conditions.