My Kidney Is Fine, Can't You Cystatin C?
Level 4 - case-series / case-control
Single clinical case report with narrative discussion
PubMed 38835922 · doi:10.12788/fp.0440
What was done
A case report evaluated kidney function in a 35-year-old African American man with well-controlled HIV who presented with consistently elevated serum creatinine. After an initial diagnosis of stage 3A chronic kidney disease (CKD) derived from creatinine-based estimated glomerular filtration rate (eGFR), clinicians performed confirmatory testing using cystatin C-based eGFR alongside urinalysis and other laboratory assessments.
What was found
The abstract provides no numerical laboratory values. The patient presented with isolated serum creatinine elevation that predated his HIV diagnosis and treatment, normal urinalysis and routine labs, and a cystatin C-based eGFR that ruled out CKD.
Why it matters
Confirmatory cystatin C testing can prevent false-positive CKD diagnoses in individuals where serum creatinine-based equations are inaccurate due to race, muscle mass, or metabolic factors, avoiding inappropriate medication dosing and unnecessary medical restrictions.
Limits
This is an individual case report (n=1) providing narrative evidence without reported numerical values or confidence intervals. It cannot quantify the prevalence or error rate of creatinine-based misdiagnosis across broader patient populations.
Cited by
- supports Cystatin C-based estimated GFR is not influenced by muscle mass or creatine intake, unlike creatinine-based eGFR.