Antibody question

I have been Insulin dependent for 11 years. Went straight onto insulin when I was diagnosed at age 32. Can anyone tell me whether one is able to test for antibodies like GADA etc. at this late stage to determine whether I have type 1, type 1.5 or type 2? I know the treatment will obviously remain the same but just curious…

Hi 4eyes: Based on the limited information you give, IMO you appear to be Type 1. If indeed you do have Type 1 autoimmune diabetes, after 12 years, you may or may not have autoantibodies present. If you still have some remnant beta cell function, you may have autoantibodies present. GAD in particular persists for many years. I wrote an entire blog on autoantibody testing that you may find useful. Has your doctor given you a diagnosis? Another reason to get a correct diagnosis if indeed you have T1D is that insurance is more likely to cover modern technology such as insulin pumps and continuous glucose monitors (CGMs).

I was 34 when I started using insulin, 5.11" tall, 145 lbs. I did not see a Endo or have any tests ran other than BG for about 10 years, my first GAD was positive but my last GAD ( 25 years post Dx) was negative.

Read your blog post. Thanks for info. Very thorough and informative. One doc says I’m T1 and another says T2! Hence my confusion. Think I will let them run antibodies test. Except for IAA as I’ve already used exogenous insulin. Thanks again for useful link.

Hi Melitta,
Very good info, and I didn't realize that antibodies would turn from positive to negative over time? Did I understand that correctly?

Actually, part of the problem is that these antibody tests are somewhat fuzzy and not specific. The reference ranges I've seen for something like GAD actually is positive for something like > 1.5. This means that you could still have small levels, but the test is "interpreted" as negative. Many T1s retain some residual insulin production and probably have some level of background antibody action all their life.

Sadly, doctors will still label any person with diabetes onset in adulthood as having Type 2 diabetes, because the doctor has bought into the myth that Type 1 diabetes is a childhood diseases.

Hi Denise: In Type 1 diabetes, the autoantibodies are a marker of the immune-mediated destruction of the beta cells (autoimmunity). Based on what I have read, if beta cell destruction is complete, then there is no further immune-mediated destruction, and the autoantibody markers are no longer seen. So yes, over time, a person with T1aD would go from positive to negative. However, many people with Type 1 retain beta cell function for many, many years, particularly if they were diagnosed as an adult, so autoantibodies are still present (I know one woman who had very high GAD 28 years after diagnosis--she needed to prove her Type 1 status to get an insulin pump. She got the proof, she got the pump).