Protein Cr Ratio
Calculate your urine protein-to-creatinine ratio (PCR) to assess kidney function and proteinuria severity. Get classification, charts, and 24-hour proteinuria estimate.
About This Calculator
The urine protein-to-creatinine ratio (PCR) calculator helps healthcare professionals and patients assess kidney function by comparing the amount of protein to creatinine in a single spot urine sample. This test is a convenient alternative to 24-hour urine collection for detecting and monitoring proteinuria, an early sign of kidney damage.
The PCR is calculated by dividing the urine protein concentration (mg/dL) by the urine creatinine concentration (mg/dL). The ratio corrects for urine concentration, making spot urine testing reliable. The result is expressed in mg/mg (or mg/mmol) and used to classify proteinuria severity: normal (below 0.2), mild (0.2–1.0), moderate (1.0–3.5), or nephrotic-range (above 3.5 mg/mg). An estimated 24-hour protein excretion is also provided based on standard conversion formulas.
Regional Notes
India: PCR testing is recommended by the Indian Society of Nephrology for diabetic kidney disease screening. Values above 0.2 mg/mg warrant further investigation. Medicare covers PCR testing for at-risk patients.
United States: The NKF-KDOQI guidelines recommend PCR for initial proteinuria assessment. PCR above 0.2 mg/mg (200 mg/g) is abnormal. Medicare and most insurance plans cover spot urine PCR testing for CKD screening.
United Kingdom: NICE guidelines (CG182) recommend PCR as the preferred test for proteinuria quantification. A PCR above 45 mg/mmol indicates significant proteinuria needing nephrology referral.
Frequently Asked Questions
What is the urine protein-to-creatinine ratio (PCR)?
The urine protein-to-creatinine ratio (PCR) compares the amount of protein to creatinine in a spot urine sample. It is used to estimate 24-hour urinary protein excretion and assess kidney damage or proteinuria severity. A normal PCR is below 0.2 mg/mg (200 mg/g).
What is a normal protein-creatinine ratio?
A normal urine protein-to-creatinine ratio is less than 0.2 mg/mg (or less than 200 mg/g, approximately 30 mg/mmol). Values between 0.2 and 1.0 mg/mg indicate mild proteinuria, 1.0 to 3.5 mg/mg indicates moderate proteinuria, and values above 3.5 mg/mg indicate nephrotic-range proteinuria.
How is the protein-creatinine ratio calculated?
The protein-creatinine ratio (PCR) is calculated by dividing the urine protein concentration (mg/dL) by the urine creatinine concentration (mg/dL). For example, if urine protein is 30 mg/dL and urine creatinine is 100 mg/dL, the PCR is 0.3 mg/mg. The result can also be expressed in mg/mmol by multiplying by 0.113.
What conditions cause a high protein-creatinine ratio?
A high protein-creatinine ratio can be caused by diabetic nephropathy, glomerulonephritis, nephrotic syndrome, hypertension-related kidney damage, pre-eclampsia in pregnancy, urinary tract infections, autoimmune diseases like lupus, and certain medications including NSAIDs and ACE inhibitors.
How is PCR different from ACR (albumin-creatinine ratio)?
PCR measures total urine protein (albumin and globulins), while ACR measures only albumin. PCR is a broader test preferred for initial proteinuria screening, while ACR is more sensitive for detecting early diabetic kidney disease in IN, US, and UK clinical guidelines.
Is this calculator a substitute for medical advice?
No, this calculator provides educational estimates only and is not a substitute for professional medical diagnosis or laboratory testing. Always consult a nephrologist or healthcare provider to interpret your urine test results and determine appropriate treatment.