There is no rigorous publication on the biological variation of common hematological parameters in South Asians to date. Also, there are few publications worldwide dealing with a variation of Reticulocyte parameters. Therefore, an attempt was made to estimate the short term within-subject and between-subject biological variation of common hematological and reticulocyte parameters. Twenty-eight healthy individuals (fifteen males and thirteen females) were selected after clinical and laboratory examination. Blood was collected in K3-EDTA vials in the morning for six consecutive days and analysed in triplicate on the Sysmex XN-1000 analyzer. Outliers were excluded and the within-subject, between-subject and analytical coefficient of variation calculated after statistical analysis by nested repeated measures ANOVA. The Reference change values (RCV), and estimates for desirable imprecision, bias, total error and index of individuality calculated. The within-subject biological variation for the studied subset belonging to South Asia closely followed published European and American studies and were similar for males and females. The between-subject variation showed differences from the published studies for white blood cells, platelets, red blood cells, hemoglobin, platelet indices and reticulocyte hemoglobin as well as between males and females for hemoglobin, red blood cell count and hematocrit. All the indices of individuality were low. This study supports the contention that the conclusions from within-subject biological variation for common hematological parameters are important and transportable to a South Asian population for short-term serial measurements. For quality specifications dependent on between-subject variation, the lower estimates from European and American studies should be used.
Keywords: biological variation, individual; count, erythrocyte; count, leukocyte; count, platelet; count, reticulocyte; volume, mean platelet; within-person variation.