Abstract
Red cell pyruvate kinase (PK) activity was correlated with haematological parameters. A statistically significant negative correlation was obtained between the activity of PK and total haemoglobin, total red blood cell count, and packed cell volume, and a positive correlation with white blood cell count, reticulocyte count, and red cell indices in anaemic patients. In non-anaemic patients the correlation between PK and haematological parameters was similar except with reticulocytes, where a slightly negative, statistically non-significant correlation was obtained. It is suggested that in patients with anaemias, infections, and leucocytosis, the elevation in PK level will significantly mask PK deficiency due to associated PK deficient variants. It is therefore essential to eliminate white cells before conducting PK assays, and to make corrections for reticulocytes.