Studies on osmotic fragility of red blood cells determined with a coil planet centrifuge for workers occupationally exposed to lead.

In order to clarify the relationship between lead exposure level and osmotic fragility of red blood cells determined by the coil planet centrifuge method, several clinical laboratory examinations were performed on 27 male workers employed in a scrap lead refining factory using as controls 40 male workers employed in railway construction. The examinations included measurement of red blood cell and reticulocyte counts, hematocrit, MCV, blood and urine lead concentrations, urine coproporphyrin, and urine delta-aminolevulinic acid. The results were: 1. Osmotic fragility of red blood cells was lower in lead workers at all three hemolytic points compared with the controls. Significant difference was observed in hemolysis of the maximum point (P less than 0.05). 2. The red blood cell and reticulocyte counts, hematocrit value and MCV of the lead workers were not significantly different from those of the controls. Values for blood and urine lead, coproporphyrin, and delta-aminolevulinic acid of the lead workers were much higher than those of the controls (P less than 0.01). 3. In lead workers, close relationships between the osmotic fragility and these laboratory findings were observed: blood lead, r = -0.572, P less than 0.01; coproporphyrin, r = -0.608, P less than 0.01; delta-aminolevulinic acid, r = -0.559, P less than 0.01; urine lead, r = -0.453, P less than 0.05.