Lead poisoning and thalassemia trait or iron deficiency. The value of the red blood cell distribution width.

The cause of microcytosis and anemia in lead poisoning was investigated using red blood cell distribution width as a screening parameter in 21 consecutive patients with lead poisoning and seven nonrandomly selected patients with iron deficiency and lead poisoning. Of the 21 consecutive patients, 11 had microcytosis as defined by a mean corpuscular volume of less than 72 fL, nine had thalassemia trait (alpha or beta), one had both alpha thalassemia trait and iron deficiency, and one had iron deficiency. The red blood cell distribution width was less than 17.0 in those with thalassemia trait and greater than 17.0 in the iron-deficient subjects. Results of our study suggest that microcytosis in children with lead poisoning is due to coexistent iron deficiency or thalassemia trait. The red blood cell distribution width may be of value in the rapid assessment of the cause of microcytosis in children with lead poisoning.