Quantitation of hemoglobin F. An interlaboratory study.

Samples of whole blood from four hematologically normal adults and from two individuals with increased fetal hemoglobin levels were shipped to laboratories participating in the 1976 and 1977 Center for Disease Control (CDC) hemoglobinopathy proficiency testing surveys. The data from these surveys were used to evaluate the interlaboratory variability of current methods used to quantitate hemoglobin F (Hb F). Results of Hb F quantitation obtained from more than 100 laboratories than voluntarily participated in the survey were compared with those obtained from 21 reference laboratories. Individual values for all samples varied greatly among laboratories and among methods. Results returned by most of the laboratories were outside two standard deviations of the reference laboratory mean and were not accurate enough to differentiate between a normal level and an increased, abnormal level.