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Lab Results and GFR Calculations
KristieH posted:
I have concerns about my labs. I follow them very closely and keep a spreadsheet of everything. My GFR is declining again and my creatinine is up and down as well. There is a test my doctor ordered that I have never seen before. Pro+Creatu (random). I have seen it separated but not under this grouping. My numbers are off the chart. Has anyone seen this? Should I be concerned? Also, in determining GFR, would the lab be more accurate or the calculation you do online through a site like the National Kidney Foundation? The reason I ask is the lab states my GFR is 36, but the calculations show 32, which is much more dangerous.

My question is two part. How accurate are the labs in determining GFR? I did several online ones and my GFR was 32, but my lab is saying 36. Also, my doctor ordered a different test than usual and I am concerned about the outcome, should I be?

Renal Panel
Creatinine Serum 1.70mg/dL
BUN 41mg/dL

Prot+Creatu (Random) Reference Range
Creatinine, Urine 48.6 15-.0-278.0 mg/dL
Protein, Total, Urine 105.9 0.0-15.0 mg/dL
Protein/Creat Raio 2179 0-200 mg/gcreat
john-skpt responded:
Remember that almost all of these numbers are eGFR, the e being ESTIMATED. Those are never all that accurate. There are specific tests for GFR that are more accurate, but they are a lot more time-consuming and expensive to do, so very few docs bother with them these days.

There are different 'models' that the calculators use for figuring eGFR, most use the Cockroft-Gault model, some use the newer--but not really more accurate--CKD-EPI, or the Mayo Clinic model. There are a lot of options.

About the other test, I suspect that you refer to Protein:Creatinine Ratio testing. Again this is a quicl mathematical estimate, but over the years it has been shown to be relatively consistent across a wide number of patients. It does not come out with a result that can be directly compared to eGFR since it is expressed without units of measure rather than ml/min/1.72 m squared.

But without going to the trouble and expense of doing a real iothalamate-125 radionuclide test, it may be the best that you can get.
KristieH replied to john-skpt's response:
Thank you I feel better about it now

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