misdiagnosed as type 1 ?

Hi. I know nothing about urine c-peptide tests only a bit about c-peptide blood tests and for the latter taking insulin does not influence the result as only the body's own insulin comes with the associated enzyme that is measured. It's very unusual for the pancreas to recover and produce more insulin but can happen. What amount of insulin and types have you been taking? I wonder why the doc thought to test you for a revised diagnosis?

I'm on insulin (obviously) and I had a completely non detectable urinary c peptide test while on insulin, like you I wasn't told not to take for the test. I don't think it effects the test (but I am basing that on blind faith rather than and actual research).

However, a cpeptide test is not a test to determine what type of diabetes you have. If you have cpeptide it simply shows that you are producing some of your own insulin.

Urinary c peptide of 2.9 is high for a type 1 over 5 years diagnosis. But that doesn't mean you aren't type 1. Plenty of LADAs / 1.5 continue with significant residual beta cell function - because this condition is slow onset type 1 where it takes ages for the beta cells to die.

You might want to look into genetic testing & MODY - there is a diabetesgenes.org website.

But, before you will get a genetic test, they will want to test for antibodies - have you had a GAD test?

I don't think it's anything to be concerned about. It sounds like you presented with a textbook type 1 presentation. It's pretty standard that in those circumstances they don't do further diagnostic tests, they just treat it as type 1. If you need the insulin to manage your blood sugar, then being managed as type 1 isn't doing you any harm at all. I suspect it's exactly the same as you would have been treated regardless of what type of diabetes is meaning you need the insulin.

While your cpeptide is high for a long standing diabetic, I have no idea what the reference range for a non diabetic is - I am going to assume significantly higher. Whatever insulin you are producing, it's probably a lot less than someone with a working pancreas.

See if you have had GAD test. Look at LADA/1.5 definitions. And ask about genetic testing for MODY.

What is your HbA1c? What has prompted them to look into your type status? I know when I had GAD & cpeptide tests it was because the DSN was convinced I was type 2 because I was having random hypos overnight (she was wrong, I'm convinced it was lantus causing it) but my point is, they don't usually do GAD testing unless there is a query over type status.

It is possible to be a type 1 with insulin resistance (which is not the same as moving from type 1 to type 2, because that is not a thing) and there are plenty of type 1s on metformin to help with insulin resistance.

Having a long honeymoon (I.e. A long time post diagnosis when you're still producing your own insulin) does not determine that you are not type 1. If your hba1c is high I'm not sure a move to reduce insulin is the best plan and you might want to discuss this with your doctor a bit more, if I were you, I would be sure to discuss:

- your presentation on diagnosis (which is textbook type 1)
- your family history & your mums type 1 diabetes
- ask if you have had a GAD test and if not, ask for antibody testing
- ask for genetic testing if the GAD test is negative
- ask what the normal (non diabetic) reference range is for a urine c peptide test is - how far outside of this are you
- ask what the plan is for reducing your high hba1c without insulin, if the plan is to wean you off insulin

If you're concerned about the plan going forward maybe get in touch with your doctor to explain that you aren't sure of his reasons for weaning you off insulin, what your diabetic status is or what the plan is for managing your high hba1c now. If you have an email address, at least it would all be in writing to discuss at your next appointment.