Z score analysis: A novel approach to interpretation of an erythrogram.

Context: Z score defines the shift of an observed value from the mean.

Aims: By determining the direction of this shift and its absolute value for mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC), one can quickly screen the hemogram for any spurious results in RBC parameters and also predict the type of anemia. This is because MCH and MCHC are derived parameters (from Hb, RBC, MCV) and thereby reflect the true as well as false changes in an erythrogram.