Red blood cell zinc protoporphyrin testing for iron-deficiency anemia in pregnancy.

The diagnostic value of ferritin, transferrin saturation, and red blood cell zinc protoporphyrin for detecting iron depletion and predicting third-trimester anemia was studied in 87 women attending a private obstetrics clinic. A decline in ferritin and transferrin saturation and an increase in red blood cell zinc protoporphyrin levels were observed in third-trimester measurements when compared with those of the first trimester. Third-trimester anemia (hemoglobin less than 11.5 gm/dl or 115 gm/L) was detected in 13 (15%) women. Red blood cell zinc protoporphyrin was the only test that consistently demonstrated significantly different mean values between anemic and normal subgroups. The diagnostic sensitivity and predictive value of red blood cell zinc protoporphyrin for evaluating iron depletion and risk of anemia in pregnancy compared favorably to those of ferritin and transferrin saturation measurements. The operational simplicity and low cost of red blood cell zinc protoporphyrin measurements are additional characteristics that favor this procedure for office testing.