Anyone here test negative for GAD, IA2, & Insulin Ab?

Hi all, new here.

I am negative for these 3 antibodies, with postmeal C-Peptide around 2.8, but a 13.7% A1c at Dx.

HOMA-IR & QUICKI show extremely good insulin sensitivity.

Curious if anyone else here came up negative for all these (and positive for another?)

Yes, I may be MODY or Type1b, but doesn’t seem to be any groups here for that no longer exists.

You may be interested in posts written by TuD member, @Melitta. She covers the antibody testing thoroughly. There are more than three antibodies to check for type 1 diabetes. Here’s a link to one of Melitta’s posts that may add some new information for you.

Welcome to TuDiabetes! This community can be very useful for managing diabetes, no matter the type. Please update us with whatever you discover that might help someone else here.

1 Like

Huh, I read in the medical literature that ICA is an old, superceded test. That no one has it exclusively (and not IAA, IA2, GAD, ZnT8). In other words, there is too much overlap (99% with IAA IA2 & GAD) for it to be diagnostically useful. I could still be that 1%…

I haven’t done Zinc Transporter yet, because of the cost, but there is about a 5% chance of a T1d having it exclusively.

In any case, I hope to poll the community to see if negative results for these 3 has happened to anyone else!

(Attached, argument against usefulness of ICA after testing other 3 antibodies)
Gorus1997_Article_IA-2-autoantibodiesComplementG.pdf (46.7 KB)

I started out with numbers much like yours. I think my A1C was about the same in the 13% range but my C-peptide was higher like 3.5.

I began treatment with Metformin and Victoza only and it worked for a year or two. Then I had to add Levemir too. Finally added Novolog for meals.

In all this I got a CGM paying out of pocket due to frequent hypos. Also around here my C-Peptide had dropped to the 2 range. My doctor checked every 6 months but only once for my negative antibodies.

On another year and I found I needed a pump due mostly to the hypos. I could then adjust things fast enough and also turn off the insulin for exercise so my hypo attacks about vanished. (Levemir was great but had some limitations when some days I needed about 10 units of basal and the next day I might need 30 units!)

Took another year or two and finally my C-Peptide dropped enough for Medicare to begin covering my diabetes!

All during this I managed to lose about 80 lbs as I got worse and worse. Still working on that but my A1C is now in the mid 5% range.

I just got my Tslim updated to Basal IQ which makes life much simpler esp for exercise.


Huh, odd. So if metformin worked (just made me sick), then you had a high glucose resistance? Or didn’t check this?

Because I was so thin (about 125lbs) doctors didn’t even consider Type 2, even tho I was in my 30s. We actually crossed fingers that I would be T2 and just change my diet and exercise.

I would be very curious, now that your disease has advanced so far but still have some C-peptide, what your antibodies would be. With such a shifting treatment regimen, I’m surprised your doctors aren’t curious. If they just retested and showed Medicare a positive antibody result, I don’t think they could have refused care.

Metformin and Glipizide failed very quickly for me.
Since Victoza and the like are extremely expensive compared to my current treatment (20U basal / day), and I am not overweight, I cannot try them, unfortunately.

I actually joked with my Endo how fat I’d have to get before the insurance would cover Trulicity, Victoza, etc. Her answer was like gain 150 more pounds, lol!

My regular doctor put me on Metformin because it was standard. I have no idea how bad my resistance was. I then went to an Endocrinologist because I could not get my A1C down below about 10%. I was then started on Victoza and soon after insulin where it was off and on at first. I remember going long as a month on insulin and then having a vacation of 2 weeks where I didn’t need any. So I don’t see any shifts in my treatment at all except as I got worse I added more insulin.

My first big change was to get a pen that could dose in half units!

Then I got CGMS and a pump so I could finally get my A1C under 6%, without getting hypo’s several times a week.

The only other change was stopping Metformin which I did after it started making me sick after years with no big problems from it.

My latest change is the Tslim X2 with IQ. This lets me sleep through the nights now without alarms but isn’t really a new treatment. Just makes life easier and safer.

Regarding anti-body tests I think they felt once was enough when I tested negative and once the C-Peptide dropped enough for Medicare they no longer cared. I also got the impression my doctor thought I might have anti-bodies but just not the ones they know how to test for yet.


That’s quite an improvement!

Unfortunately, even though my diagnosing doctor said “Metformin is extremely unlikely to work for you”, it is standard practice to start everybody on it. Just another messed up insurance & malpractice issue in the US. Forced to do the first-line treatment before the others.

Luckily I could quickly show, within a month, that my BGs didn’t change with it.

It definitely seems like LADA then. I’ve heard a few LADA stories now that have negative antibodies, initially. But I have yet to find someone that can survive only on Basal (without getting hypos).
It was Bolus insulin that was causing me huge problems. Alone or combined with basal.
But my body seems to compensate (to prevent lows) no matter how high my basal gets.

You were lucky I think. Metformin got my A1C from 13+% down to 10%
at best. The problem was the doc and diabetes nurse were quite
happy and thought a little exercise would fix it all up. They would
tell me how great I was doing when I knew I wasn’t. I had to refer
myself to an Endocrinologist that could see immediately I needed more.
Within a year I needed basal insulin and the Victoza handled meals more
or less. I started with small doses like 2 units of Levemir and even
with that I had to stop some to keep glucose high enough. I gradually
needed more just to keep fasting glucose under 150.

Another year or so and the Victoza stopped working as an insulin booster
and I had to add full basal bolus. Victoza is still needed mostly
to calm my liver or reduce it’s glucose storage I think but has no
effect any more for boosting pancreas output and lowering insulin doses.

I have full type 2 from all standard criterion like overweight,
metabolic syndrome, older age, etc but my insulin use and the rate of
change seems to match what I’d expect with LADA.

It seems I was lucky from the horror stories I hear. Surprisingly on a Medicaid-accepting APRN (& Endo!) But I was super skinny after losing 30lbs, in ketosis, young, etc.

I also always brought in research, detailed daily charts, and ideas, so maybe it gave me more trust? They ordered almost every test I wanted that insurance could cover.

Did you never do your QUICKI / HOMA-IR calculations? I keep hearing people getting T2D diagnoses without ever doing a proper test for insulin resistance. Seems weird.

I don’t think it is unheard of for overweight T2D to gain severe insulin resistance over a short period, so perhaps not LADA? I know T2Ds on anywhere between 10U and 200U+ insulin.

Doesn’t explain Victoza and Merformin losing effectiveness, tho, I stopped researching Type 2 oddities after my insulin resistance tests came back perfect.

The thing that drives my endo crazy is how my Glipizide seemed to work (just enhancing my natural response, never lowering my fasting BGs)
And how my basal works (20U+ and I cannot get hypo while fasting)

I never even heard of your QUICK/HOMA-IR calculations. I’ve always
read that insulin levels could be measured but it was difficult and
expensive so was not normally done.

Besides the anti-bodies and C-Peptide they never did any other tests
(besides tracking glucose levels or A1C) and those didn’t happen till I
started needing more and more insulin very suddenly. My basal insulin
needs started at 0 to 2 units a day and went to 35 a day. It was not
a gradual increase but it happened in steps with a sudden dose increase
each year for a while. The big jumps seemed to happen after a flu or
cold. My C-Peptide levels tested every 6 months seemed to drop in
proportion to these changes.

The last few years I have been pretty stable and I do far less exercise
than before I got diabetes. I used to walk or ride a bicycle to work
just for weight loss efforts but that all stopped once I started getting
hypo attacks. I would go for just 20 min walks OK but any longer and
I could need around 100 carbs or more of candy just to make it home.
I tried to exercise to lose weight so it was a waste! Walking
dropped my glucose but it then went extra high soon as I stopped so no
overall benefit there. Then it could make me go low (like around 40)
during the night unpredictably.

The Metformin didn’t lose effectiveness but just never did very much.
When I had to stop I noticed little effect.
The Victoza started to lose effectiveness for treating my meal peaks
within the first year or two. I think it still helps me eat less food.

I have also experimented with dropping the Victoza but seem to need it
to get my glucose down at 2 hours after a meal. Without it I tend to
stay high for 4 or 5 hours. I can’t compensate with just more
insulin since then at 5 hours I’d go too low.

The gold standad to test insulin resistance is called a “euglycemic clamp” and is usually only done during medical studies because they need to put an IV in you and monitor for hours.

But the HOMA-IR is the next best thing. All you need is your Fasting BG & Fasting Insulin test and put the results in a calculator. You can take exogenous basal insulin for the test, as it just concerns the ratio between the fasting tests. Your natural production (C-Pep) is irrelevant.

I’m amazed how many atypical diabetics never get this simple, cheap test!

If your insurance or doctor don’t wish to do it:

Do you not use a Freestyle Libre or other CGM? I usually use this with a very detailed food log to see exactly how much exercise, and how many carbs, affects my blood sugar. The app “Diabetes: M” will show a chart that tells exactly how much insulin you have in your system.
There are other apps that estimate how many carbs are in your system too.

So I can see during the exercise exactly how my body is reacting and compensate if needed. This has also been very useful to see if other Diabetes treatments like Berberine, Cinnamon, etc. work at all.

In any case, caloric restriction is the best way to lose weight. Keeping a detailed food log has been very helpful for me in my diabetes treatment and bodybuilding before that. Just takes some practice to estimate the size/weight of food, and very good habits to enter the foods. I find “MyFitnessPal” to work the best.

1 Like

Hi Oni,

I am new to this forum; so I haven’t seen many of the older or even recent posts. Your post really got me thinking- I was hoping I could pick your brain a bit.

I’m 47. I was “Pre-diabetic” for a couple years. Last year, I had an A1c of 6.0 and decided I needed to change course. I went on a Ketogenic diet, lost about 15lbs (my BF is around 10% now); and am feeling great. A1c has come down to 5.4.

Honestly, I feel confused about where I stand, though. I have calculated my HOMA-IR: it was 1.09 when I had the A1c of 6.0. At that time my insulin level was 3.8.

To me- those don’t seem like numbers typical of Type II; I wonder if they correlate with “Pre-diabetes”? Furthermore, if you are familiar with HOMA-B; at that time mine would have calculated to 25% (which is not very good).

Following a keto diet my HOMA-Ir has gotten even lower- 0.4 and my fasting insulin 1.8. I was worried that my insulin is low bc I’m not making it- so I recently checked my C-Peptide. Fasting level was 1.3 (seems kinda low). I also did the ab tests (they all came back negative).

In the end I may just be a paranoid pre-diabetic; but I would appreciate it if someone could explain why these numbers don’t make sense to me. Not to many people, I’ve talked to bring up HOMA scores and ab tests and c-peptide levels.


Wait for me to get on a computer to thoroughly answer your question. But as to HOMA-B, which seriously seems quite rare to use, this quote may show how your interpretation is mistaken:


To report β-cell function in isolation

HOMA apportions the basal state of insulin and glucose in terms of resistance and β-cell function. It can be seen from the model that for individuals with normal glucose levels, HOMA solutions might indicate 100% β-cell function and 100% insulin sensitivity, or, in the case of a thin, fit individual with high sensitivity, 50% β-cell function and 200% insulin sensitivity. Within the context of reporting both results, these are appropriate solutions—sensitivity is doubled, so the β-cells are functioning at 50% of normal. However, if the β-cell data are reported in isolation, one might conclude erroneously that the subject had failing β-cells, as opposed to appropriately low secretion, because the sensitivity of the body was high.

I sure need to look up some stuff, like Type1b. I have never heard of HOMA-IR, etc. When I asked the new CDE if those test like GAD were ever done. She said yes but couldn’t find them in my chart.

I asked my family doctor who first diagnosed me, he said ‘yes’, but I don’t believe him. As I recall, my BG went from 150 to an A1c close to 12 or 13 in just a few weeks (a lot of peeing and weight loss). As far as I know, only the A1c was done. My recent C-peptide had dropped to .8 (different labs have different measuring standards).

Doc told me I will always need insulin because of low pancreas function, that insulin resistance is not my problem. Being on a TslimX with Basal IQ, I sort of consider myself to be a Type 2 minus .25 (1.75). I relate more to the Type 1 and LADA forums.

So now to research all the new (to me) information mentioned above.

1 Like

I’m getting increasingly surprised how little other diabetics I’ve talked with know about the condition, diagnostic criteria, medical labs, research, etc.

My Endo APRN & Diabetic Educator friend didn’t recognize what HOMA was! I don’t know why the majority of doctors (other than mine) seem to not do proper insulin resistance tests as well as autoimmune & β-cell function tests. I assumed all 3 were essential to do a proper differential diagnosis.

I’ve decided to compile all my medical research and discussion with various doctors and researchers and put it somewhere. Maybe a subreddit or wiki. This will include a flowchart with all the criteria used for diagnosing different diabetes and related diseases.

I don’t really understand the terms “1.5” or “1.75”
There are multiple different causes, treatments, and results of diabetes, but no spectrum of “how t1 or t2” you are.
Kind of confuses me when people use these numbers like they are actual number values with meaning. If doctors called them Type A and Type B in the beginning, we wouldn’t say Type A.5 :man_shrugging:

There is no such thing as a type 1.75. I just made that up because I don’t fit into the usual Type 2 conditions. Thus 2.00-.25=1.75

1 Like


“1.75” was a joke. I thought it was quite funny.

You never heard of “1.5”? Seriously?

Hi Oni,

Thanks for the reply! I came across that article a short while ago and made me think- that could be my problem.

Can i run a scenario by you?

So maybe I’m not using the Homa score properly- bc I’m very “insulin sensitive”. But I’m only “insulin sensitive” bc my Homa score tells me so; My A1c of 6 (the original problem) doesn’t jive with that. Unless there is something weird about my A1c(unique to me). Or maybe I’m insulin sensitive while I’m on Keto- so that’s good at least. Would there be any utility in going off Keto for say two weeks and doing a glucose tolerance test or the “Kraft” insulin assay test? Could i do those tests while on Keto? I guess assuming i plan on continuing to eat Keto.
Admittedly it’s hard for me to express these thoughts- hope the questions make some sense- either way i appreciate the response.