
March 11, 2001
Blood Tests and Insulin Injections
Question from Simpsonville, South Carolina, USA:
My 10 year daughter has had type 1 diabetes since age four and one-half, and her current HbA1c is 6%. Could you please tell me the difference between the glycosylated hemoglobin test and the HbA1c? I know they basically measure the same thing (how much glucose binds to the red blood cells), but my daughter’s doctor insists on the HbA1c and my daughters friend gets the glycosylated hemoglobin, which does not require blood to be taken. The girls also compare results, and I heard somewhere that the results of the glycosylated hemoglobin may read lower.
Answer:
For practical purposes glycosylated hemoglobin and hemoglobin A1c mean the same thing. However, different laboratories measure this in somewhat different ways and with different instruments, so that it is quite possible for the same blood sample to read somewhat higher or lower in one laboratory than another. the important thing from a clinical point of view is to use the same methodology each time for the same person. Whatever the procedure, it does need a blood sample, but it may be that your daughters friend gets a very small needle stick sample taken directly into a capillary tube cartridge that then does the test at once in the doctor’s office whilst your daughter has a venipuncture which is then sent to an outside clinical laboratory.
DOB