Hemoglobin Determination in Blood Donors Ritchard G. Cable H EMOGLOBIN determination of the prospec- tive blood donor has been routine since the earliest days of modem blood transfusion. Hemo- globin level is the first laboratory test performed on a blood donor. However, the hemoglobin de- termination, which seems simple, is a complex as- say, and the establishment of appropriate hemo- globin standards for blood donation remains controversial. This article reviews the biological variation in human hemoglobin levels, the methods used to de- termine the hemoglobin level or hematocrit value of prospective blood donors, and the current con- troversies in the establishment of blood donor he- moglobin standards. Because many observers con- sider the primary benefit of donor hemoglobin determination to be the avoidance of significant degrees of iron depletion, this review also briefly summarizes the detection, prevention, and signif- icance of iron depletion in blood donors. Finally, this article outlines the factors impor- tant in setting blood donor hemoglobin standards and provides editorial comment on current donor standards in the United States and elsewhere, THE RATIONALE FOR HEMOGLOBIN DETERMINATION BEFORE BLOOD DONATION Hemoglobin determination before blood dona- tion is a universal practice in developed countries. The hemoglobin level is a relatively straightfor- ward laboratory assay that can be adapted success- fully to the mobile or clinic setting. However, the rationale for its use is not always clear. If hemo- globin testing were new, expensive, or appeared more complex, more attention might be paid to the assay and the standards for its use. Hemoglobin determination has drawbacks, the main one being the unnecessary deferral of donors. A hemoglobin value below the donation cutoff is the most common reason for donor deferral in the United States. Available data 1-3 show that 2% to 10% of all donors who present to donate blood are deferred because of hemoglobin levels below the cutoff. This represents approximately one third of all donor deferrals. 1,3 The variability of these de- ferral rates reflects different methods and/or differ- ent hemoglobin cutoff values. Additional draw- backs of hemoglobin testing include administrative and quality control costs; donor inconvenience, ex- pense, and anxiety as a result of medical follow-up of deferrals; and permanent loss of donors. 4 Consequently, it is appropriate to review the benefits of blood donor hemoglobin determination. Rational blood bank policy should ensure that the benefits outweigh the drawbacks. The following analysis reviews the benefits of establishing a min- imum hemoglobin level for blood donation. Quality~Quantity of Red Blood Cell Transfusions The most direct benefit of hemoglobin determi- nation is the assurance of a minimum infused he- moglobin dose per red blood cell or whole blood transfusion. In the United States, the Food and Drug Administration (FDA) has established a min- imum donor hemoglobin level of 12.5 g/dL. 5 Be- cause the FDA requirement is the same for male or female donors, it seems that the primary rationale for this standard is to assure the recipient of packed red blood ceils or whole blood a minimum hemo- globin dose of 50 g (405 mE, being the minimum volume of a unit of blood in the United States). The minimum dose of hemoglobin would be 56 g at the usual volume of 450 mL. Whereas the orig- inal rationale of the FDA might have been to en- sure the potency of a red blood cell transfusion, more recent discussions 6 of this standard have em- phasized the need to protect the blood donor from iron deficiency (see below). Another potential benefit of hemoglobin deter- mination is to detect red blood cell or congenital hemoglobin abnormalities that may affect the sur- vival or function of the transfused red blood cell, for example, hereditary spherocytosis and certain hemoglobinopathies. However, most of the com- From the Departments of Medicine and Laboratory Medi- cine, University of Connecticut School of Medicine, and the American Red Cross Blood Services, Connecticut Region, Farmington, CT. Supported by a Transfusion Medicine Academic Award (No. 5KO7-HL02527) from the National Institutes of Health. Address reprint requests to Ritchard G. Cable, MD, Amer- ican Red Cross Blood Services, Connecticut Region, 209 Farm- ington Ave, Farmington, CT 06032. Copyright 9 1995 by W.B. Saunders Company 0887-7963/95/0902-000453.00/0 Transfusion Medicine Reviews, Vol IX, No 2 (April), 1995: pp 131-144 131