Trapped plasma in the microhematocrit.

The amount of trapped plasma in the microhematocrit red blood cell column of samples from 25 normal individuals and 102 patients was investigated. The mean value for the normal individuals was 1.53%, and the mean values for the samples from the patient groups ranged from 1.41% to 1.82%. These groups included patients with sickle cell disease, iron deficiency, and hereditary spherocytosis. There was an inverse correlation between trapped plasma and the MCH in the samples from patients with iron-deficiency (MCH less than or equal to 25.0 pg). These findings have relevance to the determination of the PCV and derived red blood cell indices.