What are total glycosylated hemoglobin and HbA1?
HbA1c is just one type of glycosylated hemoglobin. The HbA1 measure includes all types of glycosylated HbA (including HbA1c) and total glycosylated hemoglobin includes virtually all types of hemoglobin affected by blood sugar level. Based upon analyses of 225 split sample specimens run by the CIC between April and October of 2000, conversion formulas between HbA1c and TGHb were calculated. The correlation between the two measures was excellent (0.966), however, assays can vary from laboratory to laboratory, so it should not be assumed that the formulas given below can be generalized to other laboratories. • It is recommended that HbA1c be used for all patient care and for newly-initiated research, since this is the assay used in the DCCT and most other clinical trials. • HbA1 tends to run roughly one point higher than HbA1c (an estimate of HbA1c can be made using the formula HbA1c = 0.9HbA1 + 0.05). • Total glycosylated hemoglobin does not have a simple linear relationship to HbA1c. It
