I posted this question on the PCOS board as well.

I don't have diabetes but I do have insulin resistance and am on metformin.

I was diagnosed with IR by doing the glucose tolerance test.  I am having surgery on Tuesday and have decided not to take metformin the month I'm on liquids because it's too complicated to get that in liquid form.

Once I lose a lot of weight how can a doctor test to make sure I still have IR if I can't do the glucose test?

Best of luck on your surgery on Tuesday.  What procedure are you having done?

 I don't really know how you will do a GT test..  I am sure some modifications can be made.  Do you test your blood sugar now at all?  I would think that your hbA1c would likely be monitored as a way of tracking your insulin resistance.

I suspect that, once you get through the post-surgery period, you will likely be restarted on metformin.  I am Type 1.5 (LADA) diabetic (which means I have both insulin insufficiency and insulin reisistance) and was off my orals for a period of time, but restarted on half my prior dose of meformin.  Can't live without it!

I'm getting RNY.

Currently I do not check my blood sugar but the issue with insulin resistance is that my blood sugar will always be normal, it's the amount of insulin in my body that changes.  My understanding is that only the glucose test can check insulin. Maybe there is a blood test that can tell?

A glucose tolerance test will show how your body reacts to a set amount of glucose/carbs.  They will test you fasting, 1 hour, 2 hour and 3 hour to see how you metabolize.  In that test, they are doing blood sugars.  That's why I asked if you checked yours because, in essence, you can perform this yourself.  I don't know that they are measuring anything but blood sugar during a 3 hour GTT.

You can have a c-peptide test (blood test) which measures your insulin production by your pancreas.  Those with Type 1 diabetes show no to very minimal insulin production.  Those with insulin resistance usually have normal to high insulin production with higher blood sugars.  So, perhaps it's your insulin production that should be measured.

I hope I'm not misunderstanding the types of tests to which you are referring?

Aha.  When i was originally tested for insulin resistance and PCOS I was told that the GTT was the only test that would tell if I had IR.

You are now telling me there is a simply blood test and so thank you. That is the information that I need so after surgery my doctors can still check to see if I have insulin resistance.

Insulin production is what needs to be tested for me because my blood sugar levels remain the same no matter what.

Thank you

Then the c-peptide test should give you the info that you need.  It's a simple blood draw, although I don't know if it needs to be done fasting or not.  If you are having other routine blood work, which you will after surgery, they can just add this to the list. 

Best of luck - so glad that you came here with questions!

You were completely right. I met with the diabetic nurse and I'm getting that test this morning.

She also said that waiting a bit to start the metformin again is fine.

Wow - glad that I got something right!  :-)  You should be fine to wait on the metformin.  I used to take 2000 mg per day and went without for about 2-3 months.  I started back at half the dose - no problems. 

You go girl!  Keep up the good work!