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Distribution of hemoglobin F, A, S, C, E, and D quantities in 4 million newborn screening specimens.

The California newborn screening program requires that all newborns be screened for selected hemoglobinopathies. Dried blood spot (DBS) specimens are analyzed using an automated 2-min cation-gradient HPLC method that is sensitive and specific (1)(2). The standardized method selected by the State allows the screening program to match the quantitative analytical performance of the assay at eight private contract laboratories and a central laboratory. Information technology is designed to derive phenotypes automatically and to use quantitative acceptability limits for quality control and proficiency testing.

The distribution of hemoglobin (Hb) quantities determined by cation-exchange HPLC in cord blood specimens has been published previously (3)(4). We have determined the frequency distributions for the analysis of DBS specimens using the rapid HPLC screening method. In this study, we examined screening data reported on 4 million nontransfused newborns tested within 2 days of birth. The frequency distributions were determined for the percentages of Hb concentrations in 14 phenotypes containing Hbs F, A, S, C, E, and D. The frequency distributions are available on request. The medians only are given in Table 1⇓ .

The percent concentrations in the current study are lower than the published cord blood data by 15% for all Hb F and by a median 36% for the Hb in other hetero- and homozygous patterns (range, 22–40%). This may be caused by differences in the HPLC methodology and by chemical degradation of Hb during formation of the dried blood spots (5)(6). Approximately 28–34% of the total area of the …