Which test can be used to determine total protein and creatinine clearance (CrCl) in the evaluation for chronic kidney disease (CKD), and when should it be administered?

Updated: Oct 26, 2020
  • Author: Pradeep Arora, MD; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Although 24-hour urine collection for total protein and creatinine clearance (CrCl) can be performed, spot urine collection for total protein–to-creatinine (P/C) ratio allows reliable approximation (extrapolation) of total 24-hour urinary protein excretion. In children, teenagers, and young adults in particular, a first morning urine specimen is preferable to a random specimen, as so-called orthostatic proteinuria (considered benign) can be excluded.

Patients with a P/C ratio above 200 mg/mg should undergo a full diagnostic evaluation. [45] A value of greater than 300-350 mg/mg is within the nephrotic range.


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