Re-evaluation of CKD Stage 2 Diagnosis
The initial diagnosis of CKD Stage 2 appears incorrect and should be reconsidered, as CKD Stage 2 requires BOTH an eGFR of 60-89 mL/min/1.73 m² AND documented evidence of kidney damage (such as persistent albuminuria), and your consistently normal UACR tests over 2 years indicate no kidney damage is present. 1, 2
Critical Diagnostic Requirements for CKD Stage 2
Stage 2 CKD cannot be diagnosed based on eGFR alone. The diagnosis absolutely requires documented kidney damage in addition to the mildly decreased eGFR. 1, 2
Your Current Clinical Picture
Your test results show:
- Creatinine-based eGFR: Presumably in the 60-89 range (Stage 2 territory)
- Cystatin C-based eGFR: 70.0 mL/min/1.73 m²
- Combined equation eGFR: 64.3 mL/min/1.73 m²
- UACR: Consistently normal over 2 years (multiple tests)
- Kidney ultrasound: Completely normal
Why the Diagnosis Should Be Questioned
The absence of albuminuria is critical. CKD Stage 1 and Stage 2 are specifically defined by evidence of high albuminuria (UACR ≥30 mg/g) with eGFR ≥60 mL/min/1.73 m². 3 Without albuminuria or other markers of kidney damage, an eGFR in the 60s does not constitute CKD. 2
The normal kidney ultrasound further supports the absence of structural kidney damage. While normal-sized kidneys don't exclude all forms of CKD, the combination of normal imaging AND consistently normal UACR over 2 years makes true kidney disease unlikely. 4
Understanding the Cystatin C Results
The cystatin C-based eGFR of 70.0 mL/min/1.73 m² and combined equation result of 64.3 mL/min/1.73 m² provide important confirmatory information. When creatinine-based eGFR is 45-59 mL/min/1.73 m² without albuminuria, KDIGO recommends measuring cystatin C because persons with both eGFR creatinine and eGFR cystatin C values >60 mL/min/1.73 m² have very low risk for CKD complications and could be considered not to have CKD. 3
The combined equation (using both creatinine and cystatin C) provides the most accurate GFR estimate. For determination of measured GFR, the combination of both markers provides a more precise estimate than either alone. 3, 5, 6 Your combined equation result of 64.3 mL/min/1.73 m² suggests borderline kidney function rather than established CKD.
Confirming Chronicity and Ruling Out Alternative Explanations
CKD diagnosis requires persistence of abnormalities for at least 3 months. 2 You should:
- Review all historical eGFR measurements to determine if kidney dysfunction has truly persisted >3 months or if there's been fluctuation. 2
- Consider non-kidney factors affecting creatinine-based eGFR, including muscle mass, diet (particularly protein intake), and medications. Creatinine-based eGFR can be affected by these factors even when true kidney function is normal. 3, 2
- Repeat eGFR measurements (both creatinine-based and cystatin C-based if possible) within 2-4 weeks to distinguish stable mild reduction from acute changes. 2
What This Likely Represents
Given your consistently normal UACR over 2 years, normal kidney ultrasound, and borderline eGFR values, you likely fall into one of these categories:
No CKD at all - The mildly reduced creatinine-based eGFR may reflect non-kidney factors (low muscle mass, dietary factors, or normal aging) rather than true kidney disease. 3, 2
"Confirmed GFR" category - Some individuals have mildly reduced eGFR without any evidence of kidney damage, which doesn't meet criteria for CKD and carries very low risk for complications. 3
Common Pitfalls to Avoid
The most critical error is diagnosing CKD based on eGFR alone without confirming kidney damage. 1, 2 Many clinicians mistakenly label patients with isolated mild eGFR reduction as having CKD without documenting the required evidence of kidney damage.
Don't rely on a single eGFR measurement. Biological variability means that eGFR can fluctuate by >20% between measurements even in stable individuals. 3 Multiple measurements over time are essential.
Don't skip albuminuria testing or dismiss its importance. Both eGFR and UACR provide independent prognostic information for cardiovascular events, CKD progression, and mortality. 7, 8 Your consistently normal UACR is strong evidence against CKD.
Recommended Next Steps
Request a formal reassessment of your CKD diagnosis with your healthcare provider, specifically highlighting:
- The consistently normal UACR results over 2 years (at least 2 of 3 specimens should be abnormal to confirm albuminuria) 3
- The normal kidney ultrasound showing no structural abnormalities
- The cystatin C-based eGFR of 70.0 mL/min/1.73 m², which is above the CKD threshold
If your provider confirms no evidence of kidney damage exists, you should not be labeled as having CKD Stage 2, as this diagnosis requires both reduced eGFR AND documented kidney damage. 1, 2