Volunteer blood donors who fail the copper sulfate screening test. What does failure mean, and what should be done?

Volunteers attending blood donor sessions who fail the copper sulfate screening test merit an explanation of why they are considered ineligible to donate. During a 30-month period, 0.24 percent of men and 2.8 percent of women attending blood donor sessions in the northern region of England failed this test. Their hematologic status was determined by performing complete blood counts on a venous blood specimen and measuring ferritin as an indication of iron stores in a representative sample of approximately 10 percent. Normal blood counts were found in some donors, while others had severe degrees of anemia, and such discrepancies could be clarified only by hemoglobin determinations. Iron deficiency was very common in deferred donors, including 36 of the 88 with normal blood counts in whom ferritin assays were performed. Microcytic blood cells, a hallmark of iron deficiency, were found to be a relatively insensitive measure of low iron stores, except at low levels of hemoglobin. By a check of a venous sample, the hematologic status of most volunteers failing the copper sulfate screening test can be ascertained, and appropriate review, investigation, and treatment can be undertaken.