Adult Cystatin C eGFR (Japanese Equation)
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Population: Japanese adults aged 18 years or older. Cystatin C must be measured using ERM-DA471/IFCC-standardized calibration.
eGFRcys (estimated GFR)
mL/min/1.73 m²
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Pregnancy and thyroid disorders can affect interpretation. eGFRcys alone cannot diagnose chronic kidney disease or determine drug dosing.
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JSN formula, population and limitations
Formula
For males: eGFRcys = 104 × CysC^−1.019 × 0.996^age − 8. For females: eGFRcys = 104 × CysC^−1.019 × 0.996^age × 0.929 − 8. CysC is IFCC-standardized serum cystatin C in mg/L; age is completed years. The 0.929 factor is applied BEFORE the final subtraction of 8.
Hypothetical example
Age 50 years, cystatin C 1.00 mg/L: estimated GFR 77.1 mL/min/1.73 m² (male) and 71.1 mL/min/1.73 m² (female).
Applicability and limits
Derived for Japanese adults aged 18+. It is an indexed estimate, not measured or unindexed GFR. Unstandardized assays, pregnancy, thyroid dysfunction, rapid renal change and other clinical circumstances limit interpretation. Results that are nonpositive are withheld. This does not establish CKD or provide dose recommendations.
Evidence and approval
Source verification date 2026-11-10.