Blood test end of September to the end of November- big changes in kidney function

I saw an endo for the first time last week. He ordered several tests including thyroid, thyroid antibody, C-PeptideCBC, Lipid panel and HbA1c. September 21 I had the same blood work minus the C-Peptide and thyroid antibody test. All were within range. This was 2 different labs, if that makes any difference.

BUN, Creatinine, CalcBUN/Creatinine and TSH Third Generation and thyroid peroxidase antibodies high out of range from September. C-Peptide last tested Nov 2017 was 0.8 now in the normal range of 2.2. Thyroid peroxidase antibodies test positive.

I am concerned mostly about high BUN, Creatinine and CalcBUN/Creatinine if my kidneys are going down hill. It is surprising that there would be so much change in 2 months. I don’t see the endo again until January.

Thanks for reading


Edit, just got a call and an appointment for Monday.


Those are snapshots, and there are a lot of things that can change the values. A rapid increase would generally not be a sign of kidney deterioration, because that would normally happen over time.

You could certainly wipe out your kidneys in 2 months, but you’d need to try really hard to do that.

It could be a kidney issue, but it could also be from some other causes. Medications can affect the results, and also being dehydrated or strenuous exercise.

Getting another test would be good idea. Make sure you are doing normal stuff, are not dehydrated, etc.

And as a side note - this is a great example of why I like to get the tests BEFORE the appointment, because that way you can discuss the results at your appointment.


True, exercise before a blood draw can disturb those kidney values. In that case, ask to repeat the test and then make sure you don’t exercise before the blood draw. That doesn’t have to be done immediately. Your doctor probably will want to repeat the test in a few months anyway to make sure it isn’t an outlier.


@CarlosLuis I’d listen to Eric’s advice on the testing and will send good thoughts your way for improvement on re-testing.

@Eric I’m with you on testing. My PCP has said most insurance requires an office viisit prior to authorizing labs…makes no sense! The Doc knows he/she is going to order blood tests, so isn’t the office visit just an un-necessary cost on top of the second visit to discuss/interpret? I’m sure there’s a reason some bean counter came up with, just not sure its a “good” reason…


Thanks, @TomH & @Eric I am worried but not extremely so. I have questions about the C-Peptide rise,1. Is it because of exogenous insulin use (MDI) by me a type 2 DM has rested the Beta cells? or 2. That the kidneys are less efficiently clearing the C-Peptide? or 3. A combination of the two.

My previous C-Peptide of .8 was in 2017 when I was only on Lantus. I have been on both Lantus and Humalog for 11 months.

I was really pleased with my labs from September, because nothing was out of range. This one 2 months later has 6 out of range. Hopefully you guys are right and it’s an abnormality in the lab.

Who said life is simple? :joy: :crazy_face:


Most of the times, the result for almost any test is a combination of everything. Your questions about C-Pep are legitimate. We don’t live in a bubble, all of the factors will work together to combine for the result.

We can’t really isolate any of the things very well in tests, so you have to take all the results and interpret them together. And also do them over time, so you have a history to look at, and some context.

Like for insulin usage, yes now you are taking more. And your beta cells might be making more too. Maybe you have more insulin resistance now, so your body needs to make more in addition to what you are taking. But you don’t really know unless you think about if your diet has changed much in the past 4 years, if your weight has changed, what your carb intake has been compared to previously, what your A1C is compared to before. All of those things would need to be considered together to really gauge how much insulin you are “using” now and “making” now, compared to before.

For these things, it’s really helpful to have a good endo. Not just some checkbox type of person, but someone who looks at the sum of everything - your results, your control, all your tests, your history of tests, your lifestyle - all of it.

How long ago were you diagnosed? Do you consider your control to be pretty good? Kidney problems can be a result of diabetes, but it usually takes a long time with poor control.


A lot to unpack in your excellent response.
Let’s start with my type 2 DM history. I was diagnosed in 1992 with a fBG of 450mg/dl which caused me unable to focus correctly. At the time the health care plan we were on was basically all in-house. We, my wife and I, attended 2 or 3 classes with a CDE. I was given a binder full of information. My experience with 3 different dieticians/nutritionists who were more harmful than helpful. All 3 appeared to be anorexic with a hate for food.

I was prescribed Micronase and with the help of Dr. Bernstein I had to be weaned off as it was causing hypos. For a decade I had great control with diet and exercise and a mostly stress free life.

Then while carb restricting and exercising some 10 hours per week (bicycling) my BG began to rise, even with near zero carbs and more cycling. Also my work environment became increasingly stressful.

This was the 1st progressing of T2DM for me. I was prescribed Metformin. Over time the dose was increased to max, 2000mg daily. Then Lantus was added. This dose ended up hitting 85u.

I retired which reduced stress and was able to exercise more. This enabled me to reduce the Lantus over time to 18u. Over the last few years I had to increase Lantus to 30u.

During all this time my HbA1c was under 7%, Usually in the low to mid 6%. I have always stayed on top of my BG management.

A year ago, November, fBG and postprandial BGs were rising again. My HbA1c in January 2021 went up a full percentage point in 3 months. My PCP agreed with me that I could try MDI adding Humalog to the mix. I am using a u:carb ratio of 1u:22g and a correction factor of 1u:40mg/dl. I usually used the correction at premeal bolus. i.e. if my BG is 120mg/dl I I will add an extra 1/2 unit. I do better if I can to do a brisk walk or bike ride otherwise. When I attempted to do a correction bolus mid-meal I risk a hypo.

My HbA1cs since beginning MDI have been less than 6%.I was referred to the endo because I was enquiring about getting a T:Slim pump. My reasons were more economical than need. On Medicare the pump and insulin are covered under Part B durable medical equipment, instead of Part D drug benefit.

Now I get this surprising set of results just 2 months after my last labs.

Anyway @Eric if you waded through all this without shouting TMI! thank you, it helps to release some of the stress.
Edit - My weight has been excellent, I lost some 60 pounds after diagnosis and am currently at my trim 16-17 year old weight.


@CarlosLuis I appreciate how cathartic writing out your history and experience is! I’m relatively careful of who/how I do it with…the FUD folks here can at least sympathize and relate to all the meds and D language, thankfully…anyone else and there’s so much explaining of terms it loses the usefulness of getting it out! I don’t lightly say it often, but we “feel” you!


Nothing in that history screams that you have been abusing your kidneys. Unfortunately, this doesn’t mean that you couldn’t also get a kidney disease of a different origin, or that your kidneys didn’t have a really low margin for damage. But looking at everything you posted and how well you have been taking care of yourself, I would not worry until more data comes in.


Thanks to @TomH @Eric and @Chris y’all gave me comfort. I will know more on Monday, next week.


A few things to mention to your endo, and also to ask you.

First of all, ACE inhibitors are a helpful medication that can help prevent or delay damage to kidneys. Are you taking any? They do not have many (if any) side-effects. Ask about something like this for your kidneys. Lisinopril is one example of an ACE inhibitor. Make sure you clarify that you are asking for the purpose of your kidneys, not because you are worried about your blood pressure.

The other thing you mentioned about your diet. When people do low carb, they usually swap that for something else. Like they are not generally removing carbs and replacing it with nothing.

The 2 things carbs can be replaced with are fat and protein. Neither one of these is without potential side-effects.

A high fat diet can cause problems with cholesterol, unless you are being careful to make sure the fat you are eating is primarily unsaturated fats and not saturated fats.

A high protein diet can cause your kidneys to work harder. If a person has healthy kidneys, it isn’t a problem. But for unhealthy or compromised kidneys, high protein can be an issue.

So those are some other things to discuss at your appointment.

(For the record, my personal feelings - I am a big fan of carbs and insulin. Not necessarily high carb, high, fat, or high protein, but the right amount of each for what a person needs. And for whatever carbs a person needs, the right amount of insulin to cover those carbs. Taking insulin can be very freeing for someone that is trying to balance their BG with a particular diet. But taking insulin presents a different set of challenges.)


That’s interesting about ACE inhibitors, I’ve been taking 5mg of Lisinopril for years. About 5 or 6 months ago the dose was cut to 2.5mg. That may be the issue.

I admit that I have been eating too much protein. I usually keep it around 100g or less per day. Since I started MDI I have actually lost 7 or 8 pounds, and lately have been more hungry than usual, not hypo hungry.

Anyway I have been eating 94 to 103g carbs and keeping the protein to around 100g. I think I was probably eating close to 200g protein for the last month or more. I like fats from nuts, peanut butter and do eat some saturated fats, My cholesterol is very good, no matter what I eat, 107mg/dl, LDL 51mg/dl, HDL 42mg/dl & Triglycerides 70mg/dl.

When I began bolusing I thought I could eat a med/sm apples again. I weighed and did the bolus, but BG jumped straight into the stratosphere. So I gave up. I eat frozen blueberries instead. Those are very good, but I miss the taste and aroma of a Macintosh apple.


OK, my friends, I am not normally a sky is falling guy, but I admit I was stressed for a week. My visit with the endo was reassuring. He said that my kidney function is not in the toilet, ha ha, but is OK. I misinterpreted one test and discounted another.

Will retest February 28 with an appointment on March 7. I am relieved. Between this and some family stuff causing stress, my stellar AGP took a bit of a hit.

Thanks for this family of people who are understanding because you’ve been there. :heart_eyes: Y’all are :sunglasses:


Glad the report was better than expected! Here’s hoping the tests in Feb are good as well! Perhaps the better med outlook will give enough relief that your numbers improve too!