Hemoglobins S and C: reference values for glycohemoglobin in heterozygous, double-heterozygous and homozygous subjects, as established by 13 methods.

Abstract Glycohemoglobin (gly-Hb) reference ranges of non-diabetic adults with HbAA ( n = 17 ), HbAS ( n = 37 ), HbAC ( n = 22 ), HbSC ( n = 8 ), HbSS ( n = 6 ) and HbCC ( n = 3 ) were determined by 13 methods, based on affinity chromatography, HPLC, electrophoresis and immunoassay. Gly-Hb of subjects with HbAS and HbAC can be measured without major difficulties by most methods. Some give rise to absolute gly-Hb differences ≥ 1% compared with subjects with HbAA. Measurement of HbA; 1c /total Hb cannot be recommended. Some HPLC and immunoassay methods cannot measure gly-Hb in subjects with HbSC, HbSS and HbCC, whereas others may suffer from interference. Most methods showed low gly-Hb, reflecting increased erythrocyte turnover. Use of special reference ranges requires previous knowledge of the condition (affinity chromatography and immunoassay) or separation of glyHb and its precursor Hb (HPLC and electrophoresis). Interpretation is, however, not recommended because of the numerous factors that determine erythrocyte turnover.