A comparison between haematological parameters in 'capillary' and venous blood samples from hospitalized children aged 3 months to 14 years.

In 16 hospitalized children aged 3 months to 14 years EDTA-blood samples were taken simultaneously from an anticubital vein and from a finger tip. Haematological measurements were subsequently performed in an Ortho ELT 800/WS analyzer. The thrombocyte count and the red cell indices were nearly identical in the two sets of samples. The 'capillary' erythrocyte count, haematocrit and haemoglobin values exceeded those of venous blood by 2%, and the mean 'capillary' total leukocyte count by about 20%. The relative frequency of lymphocytes, granulocytes and mononuclear cells did not alter between the two sets of samples. The significant differences demonstrated may in certain clinical settings be of medical importance. Their possible explanations are discussed.