skip to main content

Measured GFR Gold Standard — ESENeph MCQ

Instant feedback + full explanation. One question, done properly.

EasyChronic Kidney DiseaseMeasured GFR Gold StandardESENeph

A 40-year-old man with CKD G3a has a measured GFR (iohexol clearance) of 48 mL/min/1.73m2. His eGFRcr is 55 and eGFRcys is 42. The eGFRcr-cys (combined) is 49. Which value is the gold standard?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Measured GFR (iohexol or inulin clearance) is the gold standard; eGFRcr-cys is the best available estimate when measured GFR is not performed

Measured GFR (mGFR) using exogenous filtration markers (iohexol, inulin, 51Cr-EDTA, 99mTc-DTPA) is the gold standard for kidney function assessment. KDIGO 2024 recommends mGFR when high accuracy is needed (e.g. living donor evaluation, drug dosing for narrow therapeutic index drugs, significant discrepancy between eGFRcr and eGFRcys). Among estimated equations, eGFRcr-cys (combined) has the best accuracy and precision. 24-hour creatinine clearance overestimates GFR (creatinine is secreted as well as filtered) and is less accurate than properly performed mGFR.

Reference: KDIGO 2024 – CKD Guideline; Soveri et al 2014 – mGFR Methods