Table 6.

Potential applications for PCR to ACR conversion equations, with recommendations and limitations

Potential ApplicationRecommendation and Limitations
Clinical: Current use (e.g., is it acceptable to test with a PCR and use the equations to estimate ACR for CKD staging or kidney failure risk prediction?)Not recommended. ACR is the preferred test to assess albuminuria.6
Clinical: Retrospective/historical use (e.g., when there is a prior PCR result but no ACR is available)Obtain an ACR when possible. If not feasible, one can use the equations to calculate the median, 25th and 75th percentiles of ACR, to estimate the likely range. Estimation is more accurate in A3 proteinuria (>500 mg/g).
Research: Prospective use (e.g., collect data on PCR and convert to ACR)Not recommended. ACR is the preferred test to assess albuminuria.6
Research: Retrospective use (e.g., to estimate ACR from historical PCR data when no ACR available)One can use the PCR and available covariates to estimate the median expected ACR. One can also estimate the 25th and 75th percentiles of ACR to estimate the likely range. Estimation is more accurate in A3 proteinuria (>500 mg/g).