Reliability of parameters of complete blood count with different storage conditions

Introduction: The complete blood count (CBC) is a frequently performed laboratory test today. This study evaluated the effects of temperature and sample storage time on parameters of CBC which could produce misleading results of clinical significance. Methods: In a cross-sectional study, CBC was checked in 102 randomly selected healthy individuals and baseline measurements were analyzed using the Sysmex XS 500i fully automated hematology analyzer. CBC was done on samples up to 48 hr of storage at temperatures of 4 ± 2°C, 23 ± 2°C, and 31 ± 2°C. Values were checked at time intervals of 6, 24, and 48 hr. Results: Among CBC parameters, white blood cell, red blood cell, hemoglobin, mean cell hemoglobin (MCH), neutrophils and lymphocytes were stable at all three temperatures up to 48 hr. Monocytes, eosinophils, MCH concentration, hematocrit (Htc), and red cell distribution width-coefficient of variation showed statistically significant changes at 23 ± 2°C and 31 ± 2°C. A significant decline in platelet count (PLT) and increment in mean platelet volume and basophil count were seen at all study temperatures up to 48 hr. Conclusion: This study shows that most parameters of the CBC are unaffected with the studied storage temperature up to 48 hr except for the PLT which should be performed within 6 hr of the post-collection time. To avoid changes in a few parameters such as Htc, it is best to store the sample at 4 ± 2°C if any delay is anticipated.