Abstract
OBJECTIVES: To evaluate the stability of complete blood count (CBC) parameters by measuring at multiple time points up to 72 h after venepuncture. METHODS: 36 samples submitted for routine haematology were measured at 0, 8, 24, 48, 72 h. 18 samples were kept at room temperature (23-25 °C) and the other 18 at 4 °C. The stability of the CBC parameters was determined by comparing the results to the 0 h sample. White Blood Cell Count (WBC), Hemoglobin (Hb) concentration, Red Blood Cell (RBC) count, Hematocrit (Hct), Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC), Cellular Hemoglobin Concentration Mean (CHCM), Mean Platelet Volume (MPV), RBC distribution width (RDW), Platelet (PLT) and Reticulocyte counts were studied. RESULTS: Most parameters were stable for 24 h at 4 °C, except for MCV, MCHC, CHCM and MPV. MCV and MPV increased after 8 h (p<0.0001), whereas MCHC and CHCM decreased significantly after 8 h. Significant changes were found for MCHC in samples kept at 4 °C for 48 h (p=0.002), and for CHCM kept for 72 h (p<0.001). Reticulocyte count stability was maintained for 24 h at 4 °C (p=0.3047). In samples kept at room temperature changes occurred after 8 h in RBC, Hct, MCV, MCH, MCHC, CHCM, MPV and PLT. CONCLUSION: CBC measurements are reliable for 8 h when samples are stored at room temperature. The only parameter stable for 72 h at room temperature was Hb. Blood samples kept at 4 °C for up to 24 h are suitable for haematological analysis.