C-peptide

I was dx. 3 months ago for blood work for surgery at 6.6 ac1. was put on metformin 500 u twice a day . changed
diet and lost 30 lbs. bg numbers avg. in 130’s. but got a 105 and 88 reading at hospital for surgery. not sure how
accurate my meter is but don’t question that I have diabetes . have blood work in oct. should I request a c-peptide test and how do they do it and would it matter knowing what the number is? by the way age is 60
and off work for rotator cuff surgery have about 2 more months to go can’t wait to get back to work been
thinking about db to much but this site has helped.