GFR lvls different

[Munkie]

I had labs done w my PCP & it said 40. Then I had them done at the nephrologist & it said 75. This is the 2nd time I've seen this. I'm confused on why the numbers r so different. Asked the nephrologist & all he said is the test r different from the PCP. Dont get me wrong, higher lvl is great, just baffles me on the difference between them. What causes that? Anyone else have this happen? 1st te this happen labs w my PCP were 54 & w the nephrologist it showed 80.

[Hidden]

Normally, I say that the GFR number is just a snapshot of the time the labs were taken, and that is usually the case. Your numbers are vastly different but you didn't say how close in time the labs were done. While they could be just that, perhaps it is the result of the technician who performed the test or the laboratory itself. Before you worry too much about the differences, look at the average of the four results. Your average is 62. That is the number you should focus on.

Your hard copy of the lab values should indicate where the tests were performed. If they don't ask your doctor's staff and they should be able to tell you. My largest difference was 12 points and those were two months apart. What I've learned since then is to be very careful of the 24 - 48 hours prior to having my labs taken. If you have been ill postpone the labs for a day or so, if you over-exercise, postpone for a day or two. Eat properly, exercise normally, and keep to your routines if you wish to have better consistency with your numbers.

[Munkie in reply to Hidden]

That does make since. Not sure how far apart were the 1st set but the recent one is about 3wks apart I think. The #s dont bother me cuz I know it's not that bad & I know they change & I'm guessin many factors can play in why the # is what it is. Only one other time I had the labs don no more than a 5 says apart when I went to the hospital for pain. My lvls showed 20 pts apart. The doc that time said my white blood cell ct was low. Still not sure what caused that.

[Hidden in reply to Munkie]

One of the reasons for a low white cell count could be a mild infection. Often you might not even be aware of it unless your body has difficulty fighting it without help. Try not to get too high or too low emotionally with any one lab draw. Keep an average of each one and only get concerned when over three or more labs you see a decrease.

The more you learn bout CKD the better you'll feel.

Have you attended the free, 90 minute Kidney Smart class in your area? If not you can find it at davita.com

Best of luck.

[orangecity41 NKF Ambassador]

Perhaps the labs use different eGFR analysis formula. You might want to check which formula was used in the calculations. I agree also with Mister Kidney, you might want to keep an average.

[lowraind]

Something else that could make a difference is how careful a lab is with your specimen. I had a report that they were unable to get a reading and my nephrologist said that the hospital staff sometimes leave the specimens out too long. In fact, the nephrology office is changing labs because of such problems.

[Marvin8]

Always always always have your Cystatin C tested as well and make sure they use the combined formula for creatinine and cystatin C. Cystatin C provides good corroborating information but is invalid if you have abnormal thyroid issues.

[Alexperk]

Check if your personal info is the same in both places. The formula to calculate GFR has to know your age, your gender, and if you are black or not. If any of the above differs in the two places, it could explain what is going on.

[Munkie in reply to Alexperk]

Good point. I'll check that out, thanks