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

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 > or = 1% compared with subjects with HbAA. Measurement of HbA1c/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 gly-Hb and its precursor Hb (HPLC and electrophoresis). Interpretation is, however, not recommended because of the numerous factors that determine erythrocyte turnover.

á-N-terminal glycated haemoglobins (HbX) in subjects with common haemoglobinopathies: relation with fructosamine and mean erythrocyte age - abstract

á-N-terminal glycated haemoglobins (HbX, by HPLC), serum fructosamine and erythrocyte polyamines were determined in non-diabetic adults with HbAA, HbAC, HbAS, HbCC, HbSC, HbSS and Hb/HPFH. The groups did not differ in fructosamine. Mean (95 percent confidence limits) percentage HbX were: 4.4 (range 4.1 - 4.8) for HbA in HbAA, 4.3 (range 3.9 - 4.8) for HbA in HbA in HbAA, 4.3 (range 3.9 - 4.8) for HbA in HbAC, 4.1 (range 3.6 - 4.6) for HbC in HbAC, 4.4 (range 4.0 - 4.7) for HbA in HbAS, 2.6 (range: 2.3 - 3.8) for HbC in HbCC, 2.0 (range 1.5 - 2.4) for HbS in HbSC, 0.9 (range: 06. - 1.3) for HbS in HbSS, and 1.3 (range: 0.8 - 2.4) for HbS in HbS/HPFH. Considering all data, there was a non-linear inverse relation between HbX and erythrocyte polyamines, indicating that percentage HbX decreases with decreasing mean RBC-age. It is concluded that HbX in subjects with heterozygous haemoglobinopathies is to be expressed as percentage HbX + HbC, not total haemoglobin. Interpretation of HbX in subjects with decreased RBC half-life is difficult. Fructosamine seems a suitable alternative (AU)

Beta-N-terminal glycohemoglobins in subjects with common hemoglobinopathies: relation with fructosamine and mean erythrocyte age.

Amounts of beta-N-terminal glycohemoglobins (HbX1c), serum fructosamine, and erythrocyte polyamines were determined in nondiabetic adults with HbAA, HbAC, HbAS, HbCC, HbSC, HbSS, and HbS/hereditary persistent HbF (HPFH). The groups did not differ in fructosamine concentrations. Mean (95% confidence limits) HbX1c percentages were: 4.4 (4.1-4.8) for HbA1c in HbAA, 4.3 (3.9-4.8) for HbA1c in HbAC, 4.1 (3.6-4.6) for HbC1c in HbAC, 4.4 (4.0-4.7) for HbA1c in HbAS, 2.6 (range: 2.3-3.8) for HbC1c in HbCC, 2.0 (1.5-2.4) for HbS1c in HbSC, 0.9 (0.6-1.3) for HbS1c in HbSS, and 1.3 (range: 0.8-2.4) for HbS1c in HbS/HPFH. There was a nonlinear inverse relation between HbX1c and erythrocyte polyamines, indicating that HbX1c percentage decreases with decreasing mean erythrocyte age. We conclude that amounts of HbX1c in subjects with heterozygous hemoglobinopathies should be expressed as a percentage of HbX0 + HbX1c, not total hemoglobin. Interpretation of HbX1c in subjects with a decreased erythrocyte half-life is difficult; measurement of fructosamine seems a suitable alternative.