Diagnostics in case of diabetes

Question

Hello,
which test is used to diagnose a diabetes in CF at the moment?
In the past, glucose tolerance tests have been performed regularly to me, now not anymore for years. When I pointed that out in the CF center, I have been told that today one would prefer the HbA1c value, as it would be more conclusive in case of CF.
Now I found some articles, which come to the exact opposite conclusion and a yearly performed glucose tolerance test is recommended. What is right, then?
Many thanks in advance!

Answer

Dear questioner,

to assess diabetic control the HbA1c is reliable enough, but it is not recommended as a diagnostic tool for CF-related diabetes, since an early impaired glucose tolerance is characterized by a delayed insulin secretion, however by a normal amount of insulin. Therefore the HbA1c appears normal. The standard method to diagnose CFRD is the oral glucose tolerance test. According to guidelines the OGTT with 1.75 g dextrose per kilogram, 75 g at most, should be performed in the fasting and calm state once a year from the 10th year of life on. The 60-minute respectively the 90-minute value is more sensitive than the 2-hour value.
Speak to your CF physician about the guidelines.
I hope to have answered your question.

Best regards,
Suzanne van Dullemen

25.10.2011