The effect of preanalytical mechanical mixing time on complete blood cell count parameters in the emergency laboratory

Abstract

Complete blood count (CBC) is one of the most common laboratory tests. Preanalytical factors like specimen homogenization affect the CBC test results. In the emergency laboratory, test time is a ciritcal parameter. Optimization of test procedures is of critical importance to give more accurate results in a shorter time period. This study was designed to evaluate the effects of preanalytical mechanical mixing times on CBC parameters and to optimize the mechanical mixing time for the analysis. Mechanical mixing time of 1 and 5 minutes (t= 1 and t=5 respectively) with a rotary type mixer and automatic mixing performed by the Coulter LH 780 (t=0) prior to complete blood count analysis were evaluated. Between t=0 and t=1 minutes of mechanical mixing, only a significant change in MPV values were obtained (p<0,05) but the change was not significant in terms of biological variation. In the comparison of t=0 and t=5 minutes of mechanical mixing;statistically significant changes in red blood cell (RBC), neutrophile, monocyte, and mean platelet volume (MPV) parameters were observed (p< 0,05).The changes were not significant with regard to biological variation. Mean corpsucular volume (MCV) values were different among t=0 and t=5 minutes with respect to biological variation but no statistically significant difference was observed. Automated mixing alone and additional mechanical mixing times of 1 and 5 minutes all yielded several results mostly within the biological variation limits. As shorter test completion times are desired in the emergency laboratory, we can conclude that extra mechanical mixnig times give no significant advantage in CBC analysis