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Confusing lab test results - please, help

donikakraeva

Newbie
Messages
1
Hello everyone!
I would like to share some confusing results that are bugging me and my family for the last three months... and maybe find some answers:
My sister is 18 years old and in September she was diagnosed with type 1 diabetes. She was immediately prescribed insulin therapy but when in 3 weeks her antibodies results were ready, they were negative (GAD65, IA2...). So her endo suggested that she could start with oral medications and from then on she has had a lot better control on her blood sugar levels (no spikes like during the insulin therapy, almost absent hypos, sugar levels 4 - 7 mmol/l most of the time). A week ago we got new results from another lab tests, showing that the range of self-produced insulin is 4.1 µU/ml (ref. 2.6 - 24.9) and the C-peptide is 1.4 ng/mg (ref. 1.1 - 4.4). In these results again GAD65 and islet cells antibodies were negative, but insulin antibodies were positive (3.7 U/ml, ref. < 0.4). Could the last result be provoked by inappropriate insulin therapy? Some signs of MODY? Does anybody has some experience with confusing results like these?
I will appreciate all the opinions.
Thank you in advance!
 
It might sound a bit like I don't know what what I'm talking about!
But, does this mean she has too much Insulin in her blood?
Does she have normal fasting bloods?
Does she hyper then hypo after a couple of more hours?

You see I don't understand the test results, I'm only a layman, maybe somebody else can decipher them for me. But I understand the misdiagnosis, as I have been there.!

Didn't the specialist endocrinologist give a clue or didn't he have a clue?
 
This page explains the significance of various tests, including insulin antibodies:- https://labtestsonline.org/understanding/analytes/diabetes-auto/tab/test/

I think it says that the insulin antibody test does not distinguish between antibodies to one's own insulin and antibodies to injected insulin. so it is possible that the raised levels are due to the insulin therapy. Quote: " ... this test is not valid for someone who has already been treated with injections of insulin. For example, someone who was thought to be a type 2 diabetic and who was treated with insulin injections cannot then have this test done to determine if he or she is a type 1 diabetic."
 
The C-peptide should be a fairly reliable guide and can be done in the presence of injected insulin. My c-peptide was 1.19 (range 1.1 to 4.4) and I found insulin was essential. My GAD was negative but it was many years since I was diagnosed and GAD becomes unreliable as the years go by whereas c-peptide becomes more reliable.
 
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