C-peptide question

I have been an insulin pump user for quite a few years. With this last pump (about 4-5 yrs. old), I just squeeked past with the c-peptides. My new reading was 1.1. Is this too high to qualify for a pump [for Medicare]? I'm hoping I can make it because I can't survive MDIs ... not enough space for all those bruises!


I am not an expert, but here is what the Decision Memo says:

"CMS has determined that fasting C-peptide levels will only be considered valid when a concurrently obtained fasting glucose is ≤ 225 mg/dL. Insulinopenia is defined as a fasting C-peptide level that is less than or equal to 110 percent of the lower limit of normal of the laboratory’s measurement method. Alternatively, for patients with renal insufficiency and a creatinine clearance (actual or calculated from age, gender, weight and serum creatinine) ≤ 50 ml/minute, insulinopenia is defined as a fasting C-peptide level that is less than or equal to 200 percent of the lower limit of normal of the laboratory’s measurement method. Levels only need to be documented once in the medical records."

So whether or not a 1.1 ng/dl qualifies really depends on you lab reference range. My lab (Quest) has a reference range of 1-3 ng/dl, so 1.1 ng/dl may just barely qualify. That being said, it also says that you only need to document it once in the medical records, so you previous test result may also be accepted. Perhaps others will chime in.

1.1 is a common lower limit for most C-Peptide tests....You made it!

I hope this is not the case but check your COMPREHENSIVE METABOLIC PANEL,if your eGFR is below < 50 mL/min/1.73 m2 you are allowed twice the lower C-Pep limit of 1.1.

I qualify under both exceptions...my C-Pep is < .05 and my eGFR has tested below ,well below < 50 mL/min/1.73 m2 many times..:-(

Before the test Hint: Fast before your test, and correct BG down to your lower limit before your blood sample is taken...:-)

In all my readings, I've never seen a lower limit quoted for fasting blood sugar. Is there one?

ps. You should correct at least 1/2 hour before the test as the half life of c-peptide is 1/2 hour.

If you have documentation of antibody positivity, then you qualify as well. One more reason to insist on the full work up early in dx.

Isn't the 1-3 the reference range for normal, Brian? If so, than the requirement would be to be below that, not above it.

Actually I read that as requiring a c-peptide below 110% of the lower limit (1 ng/dl), which would be 1.1 ng/dl.

Well, despite all the jargon I don't understand, I am encouraged. It looks like I will squeak through again. I did fast for the test and the 1.1 was a result of the lower BG. It also looks like I just might be "grandfathered" in from my last 2 pump approvals. I am hoping they don't give me a raft of s**t in this process! Thanks.


I completely missed the 110% part. That c-peptide sounds high (though I'm happy for you, Lois). Are there different maximum c-peptides for Type 1's and Type 2's on Medicare?

I guess I am ignorant. I have NO idea what all these tests and numbers mean and/or are used for. I just know that I have been approved for a pump twice in the past for a pump. I just hope that this is good enough for all the bureacrats. It seems that this method has been the best way ever used on me.

Maybe I had better figure a way to get my DR to look at that study somebody sent in this message.