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What is normal GAD range

Marie4james

Marie4james

Active Member
Messages
32
Type of diabetes
LADA
Treatment type
Insulin
Hi, I was wondering if I could get some wisdom here, rather than chasing my tail around the internet. The TLDR version is I was diagnosed as T2 after gestational diabetes. Held steady on LC diet for 10 years with small dose (40-80mg) Gliclazide. Before xmas things went haywire BG in 25+ range on very low carb and now on insulin. The DN was convinced it’s LADA and ordered GAD and C peptide. I had the GAD back today as 137. CP not back yet. I can’t find a reference range for what GAD should be and the person I spoke (not my DN) to was cagey and said we need to wait for the CPeptide to come back. Weight is spot on - but used to be underweight before kids. I can only find references to positive or negative GAD results.
 
You will have to check the units of the GAD antibodies. It's sometimes measured in units/ml. A normal result is under 5 units/ml.
 
Marie4james said:
Hi, I was wondering if I could get some wisdom here, rather than chasing my tail around the internet. The TLDR version is I was diagnosed as T2 after gestational diabetes. Held steady on LC diet for 10 years with small dose (40-80mg) Gliclazide. Before xmas things went haywire BG in 25+ range on very low carb and now on insulin. The DN was convinced it’s LADA and ordered GAD and C peptide. I had the GAD back today as 137. CP not back yet. I can’t find a reference range for what GAD should be and the person I spoke (not my DN) to was cagey and said we need to wait for the CPeptide to come back. Weight is spot on - but used to be underweight before kids. I can only find references to positive or negative GAD results.
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I feel your frustration! But TBH you are lucky that your DN has taken action to help clarify soon whether you could have LADA. Unfortunately for both C- peptide and GAD (and other autoantibodies) it is much better to interpret in the light of the reference ranges published by the actual lab carrying out the tests. Hopefully not long before your c peptide result is in and you can ask for full details on both tests.
 
Marie4james said:
I had the GAD back today as 137.
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With my test 5 or below counted as negative, anything above as positive. But I'm not sure if different units for anti GAD are used in different places.
Do you know the units? Do you have access to your lab results? Online reference ranges are usually provided with the results.
 
Marie4james said:
Hi, I was wondering if I could get some wisdom here, rather than chasing my tail around the internet. The TLDR version is I was diagnosed as T2 after gestational diabetes. Held steady on LC diet for 10 years with small dose (40-80mg) Gliclazide. Before xmas things went haywire BG in 25+ range on very low carb and now on insulin. The DN was convinced it’s LADA and ordered GAD and C peptide. I had the GAD back today as 137. CP not back yet. I can’t find a reference range for what GAD should be and the person I spoke (not my DN) to was cagey and said we need to wait for the CPeptide to come back. Weight is spot on - but used to be underweight before kids. I can only find references to positive or negative GAD results.
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Hi Marie, I am no expert but I was similar to you and remember being told that it's not a question of ranges, but whether you were positive or not (a bit like you can't be a little bit pregnant!). I think that the very presence of them meant positive other than if it was a very low 'trace amount'. Some people can have higher numbers than others but a positive is a positive. Hopefully others more knowledgeable will be along soon. x
 
Thank you both @ert, @oldgreymare for replying. I am very lucky so far that I am being treated on my clinical presentation and need. I know based on this the underlying diagnosis won’t change much, but I’m one of those people who likes to know!
My HBA1c went from 42 in November to 63 in March so something is definitely amiss!
 
Marie4james said:
KK123 said:
Hi Marie, I am no expert but I was similar to you and remember being told that it's not a question of ranges, but whether you were positive or not (a bit like you can't be a little bit pregnant!). I think that the very presence of them meant positive other than if it was a very low 'trace amount'. Some people can have higher numbers than others but a positive is a positive. Hopefully others more knowledgeable will be along soon. x
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that makes complete sense of why I can only find positive or negative terminology! Thanks!
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Antje77 said:
With my test 5 or below counted as negative, anything above as positive. But I'm not sure if different units for anti GAD are used in different places.
Do you know the units? Do you have access to your lab results? Online reference ranges are usually provided with the results.
Click to expand...
I don’t have that access - I am just phoning my BG results in on a weekly basis while they tweak the insulin and I asked if any results were back. I’ll give it a few days for the CP and see if I can get a clearer picture.
 
Marie4james said:
Thank you both @ert, @oldgreymare for replying. I am very lucky so far that I am being treated on my clinical presentation and need. I know based on this the underlying diagnosis won’t change much, but I’m one of those people who likes to know!
My HBA1c went from 42 in November to 63 in March so something is definitely amiss!
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The GAD result will help confirm whether or not your possible beta cell failure is due to autoimmune factors (indicating LADA, T1) but pragmatically the c peptide test may be more informative about whether you could be in a "honeymoon" state with fluctuating levels of your own insulin. This will help in how to manage going forward.

For example, I was originally diagnosed 12 years ago in Singapore. Presenting with fairly severe symptoms but no DKA. So my then endo put me on insulin and only tested for c peptide and GAD after 3 months and getting my HBAc1 down to 7%. Rationale was that maybe I was T2, but had exhausted my beta cells through insulin resistance. Extra insulin can help them recover. But GAD result was massively positive. At that stage my c peptide was low, but still measurable - in hindsight this meant a diagnosis of LADA, but not a term used there then. But this fit my clinical symptoms as even though I was not particularly well controlled in the first two years, it was only thereafter that I suffered a few episodes of DKA (one life threatening). Nowadays I am extremely sensitive to gaps in my basal insulin.

Fast forward to my last UK endo consult last December with a rather geeky research registrar. He was keen to recommend repeating GAD and c peptide testing as this is not recorded in my NHS results. Just had this done a couple weeks ago. My c peptide test came back effectively 0, down from a low level at original diagnosis. My GAD result is due Thursday - I'll report when I get it.
 
Antje77 said:
Are you in the UK? If so, I believe you can ask for online access to your results. It can be very helpful :)
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I think other UK based members have mentioned that it is now a requirement (within last 12 months?) for GP practices to provide online access to their test results. But this can be via a variety of access systems and not all practices are yet compliant. Plus depending on how well their records are digitised, information may take some time to be uploaded, some results may need to be reviewed by a doctor first.

But I think @Marie4james should ask her practice whether she can register for 'Patient Access'.
 
oldgreymare said:
I think other UK based members have mentioned that it is now a requirement (within last 12 months?) for GP practices to provide online access to their test results. But this can be via a variety of access systems and not all practices are yet compliant. Plus depending on how well their records are digitised, information may take some time to be uploaded, some results may need to be reviewed by a doctor first.

But I think @Marie4james should ask her practice whether she can register for 'Patient Access'.
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Yes, surgeries have to provide a level of access to their online system unless they have a good reason not to e.g. the patient has mental health problems or would worry about what they see. This is an NHS Instruction to all surgeries 2 year ago. A surgery that can't be bothered is not a good reason! I have access to both level one i.e. coded patient record and level two which includes test results. Most surgeries don't provide level three access to doctors and hospital letters and other communications.
 
Hi @Marie4james have you had any further results back from your GP? As @Daibell mentions you should be able to register for online results and hopefully not too difficult to arrange a phone call to discuss any and all of them.

So my latest results - my recent c-peptide was effectively zero, so as supported by my clinical signs looks like I am firmly out of LADA territory - full blown T1. But this is how I manage my diabetes anyway.

The GAD Ab results were more disconcerting. At diagnosis was 77 (ref range 0-5). Recent test close to 1500 (!) which suggests I may need workup for other autoimmune conditions as well as T1. But knowledge is power and so thanks to a geeky registrar I can try to be proactive re possible future health issues.
 
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