Stability of complete blood count parameters in low volume tubes under different storage conditions

Our aim was to determine the stability of complete blood count (CBC) parameters in low-volume tubes under different storage conditions. Thirty apparently healthy volunteers were included in the study. Two venous blood samples were taken into low-volume K2EDTA tubes from each individual. The samples were analyzed immediately, then one tube was stored at room temperature and the other under refrigerated conditions (+4 °C), and subsequent measurements were performed at 24, 48 and 72 h. The CBC was performed on the Sysmex XN-1000 analyzer. Stability of CBC parameters was assessed based on total allowable error (TEa) goals. White blood cells (WBCs), red blood cells (RBCs), hemoglobin (Hb), mean corpuscular hemoglobin (MCH), plateletcrit (PCT), neutrophils, lymphocytes and basophils were found stable throughout 72 h at both room temperature and +4 °C. In addition, hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and eosinophils remained stable for 72 h at +4 °C. The remaining parameters exhibited stability for less than 72 h under both temperature conditions. As a result, the stability of CBC parameters in low-volume tubes improves with storage under refrigerated conditions. However, not all parameters remain stable until 72 h, even under refrigerated conditions. For this reason, CBC analysis should be performed as fast as possible without delay.