Skip to content
Hakeemly
ع

Urine Protein-to-Creatinine Ratio (UPCR)

Calculate UPCR from spot urine protein and creatinine and estimate daily protein excretion.

For healthcare professionalsKidneyv1.1.0

For healthcare professionals / clinical use. Not a self-diagnosis tool.

Your measurements

mg/dL
mg/dL

Calculated on your device. Nothing is sent to a server.

Your result will appear here

Enter your measurements, then press Calculate.

Methodology

Spot urine protein:creatinine ratio

UPCR (mg/g) = urine protein (mg/dL) ÷ urine creatinine (mg/dL) × 1000

UPCR in mg/g is often read as approximate daily protein excretion in mg, because adults excrete roughly 1 g of creatinine a day; this is a rule of thumb, as creatinine excretion varies.

Who it is for
Adults; spot urine sample.
Version
1.1.0

How this calculator works

Where the formula comes from

  • Ginsberg and colleagues showed in 1983 that the protein-to-creatinine ratio of a single urine sample correlates with protein excretion measured over 24 hours.[1]
  • Creatinine excretion is relatively stable within an individual over short periods, allowing the protein-to-creatinine ratio to partially account for how dilute or concentrated the urine is; it is not constant across individuals.[1][2]

The inputs

  • UPCR is urine protein divided by urine creatinine from the same sample; when both are in mg/dL, the ratio is multiplied by 1000 to express it in mg/g, and mg/g divided by 8.84 gives mg/mmol.[2]
  • The value in mg/g is often read as approximate daily protein excretion in mg because adults excrete roughly 1 g of creatinine a day, but actual creatinine excretion varies between people.[1][2]

Versions and alternatives

  • KDIGO 2024 prefers the albumin-to-creatinine ratio for initial testing in adults; the protein-to-creatinine ratio is used when total protein is to be measured.[2]
  • Equations that adjust the spot ratio for estimated daily creatinine excretion, or for age, sex and weight, have been developed to predict 24-hour protein more closely.[3][4]

Where accuracy falls (published evidence)

  • KDIGO notes that creatinine ratios overestimate protein loss in people with low creatinine excretion (for example low muscle mass) and underestimate it in people with very high creatinine excretion.[2]
  • A spot ratio may differ materially from measured 24-hour protein excretion, and its agreement depends on the population and the degree of proteinuria.[5][6]

What guidelines say

  • KDIGO 2024 recommends confirming a positive dipstick result with a quantitative laboratory measurement, expressed as a ratio to urine creatinine where possible.[2]
  • KDIGO nomenclature classifies a protein-to-creatinine ratio below 150 mg/g as normal to mildly increased, 150–500 mg/g as moderately increased and above 500 mg/g as severely increased; these are proteinuria categories, not the albuminuria categories A1–A3.[2][7]
  • A ratio of about 3,500 mg/g or more is commonly used to mark nephrotic-range proteinuria, but nephrotic syndrome is not defined by the ratio alone.[7]

Sources

  1. Ginsberg JM, Chang BS, Matarese RA, Garella S. Use of single voided urine samples to estimate quantitative proteinuria. N Engl J Med. 1983;309(25):1543–1546. doi:10.1056/NEJM198312223092503
  2. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int. 2024;105(4S):S117–S314. doi:10.1016/j.kint.2023.10.018
  3. Estimation of the 24-h urinary protein excretion based on the estimated urinary creatinine output. Clin Exp Nephrol. 2016;20(3):456–461. doi:10.1007/s10157-015-1178-z
  4. Chen YT, Hsu HJ, Hsu CK, et al. Correlation between spot and 24h proteinuria: derivation and validation of equation to estimate daily proteinuria. PLoS One. 2019;14(4):e0214614. doi:10.1371/journal.pone.0214614
  5. Lane C, Brown M, Dunsmuir W, Kelly J, Mangos G. Can spot urine protein/creatinine ratio replace 24 h urine protein in usual clinical nephrology? Nephrology. 2006;11(3):245–249. doi:10.1111/j.1440-1797.2006.00564.x
  6. Ralston SH, Caine N, Richards I, et al. Screening for proteinuria in a rheumatology clinic: comparison of dipstick testing, 24 hour urine quantitative protein, and protein/creatinine ratio in random urine samples. Ann Rheum Dis. 1988;47(9):759–763. doi:10.1136/ard.47.9.759
  7. Nomenclature for kidney function and disease: executive summary and glossary from a Kidney Disease: Improving Global Outcomes (KDIGO) consensus conference. Nephrol Dial Transplant. 2020;35(7):1077–1084. doi:10.1093/ndt/gfaa153

Compiled from the published sources above. Every statement was agreed independently by three AI research tools (Claude, ChatGPT, DeepSeek) and its source verified in PubMed or Crossref by the Hakeemly editorial team. Not reviewed by a doctor unless stated. Agreed on

Worked example: how to calculate urine PCR

Inputs

Urine protein
30 mg/dL
Urine creatinine
100 mg/dL

Result

UPCR
300 mg/g (≈ mg/day)
UPCR
33.9 mg/mmol

150–500 mg/g: moderately increased (KDIGO)

Calculation:

30/100 × 1000 = 300

An illustration with sample values, worked out with the same method the tool above uses.

Limitations

  • Approximation to 24-hour excretion is less reliable at extremes of muscle mass.

References

  1. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117–S314. doi:10.1016/j.kint.2023.10.018

You may also find useful