Why was a patient with an estimated glomerular filtration rate (eGFR) of 60.6 mL/min/1.73 m² and no albuminuria initially diagnosed with Chronic Kidney Disease (CKD) stage 2 by their healthcare provider?

Why the Initial CKD Stage 2 Diagnosis Was Incorrect

The provider likely misdiagnosed CKD Stage 2 because they relied solely on the eGFR of 60.6 mL/min/1.73 m² without confirming the presence of kidney damage markers, which are absolutely required for diagnosing CKD when eGFR is ≥60 mL/min/1.73 m². 1, 2

The Fundamental Diagnostic Error

The core issue is a widespread misunderstanding of CKD diagnostic criteria that affects many clinicians:

• When eGFR is 60-89 mL/min/1.73 m² (Stage 2 range), documented kidney damage must be present for at least 3 months to diagnose CKD. 1, 2, 3
• Without evidence of kidney damage (albuminuria, hematuria, pathological abnormalities, or imaging abnormalities), an eGFR of 60.6 does not meet criteria for any stage of CKD. 1, 2
• Only when eGFR drops below 60 mL/min/1.73 m² can CKD be diagnosed based on eGFR alone, without requiring additional markers of kidney damage. 2, 3

Common Reasons for This Misdiagnosis

Confusion About the Staging System

• Many providers incorrectly believe that any eGFR value automatically corresponds to a CKD stage, when in fact Stages 1 and 2 require both reduced/normal GFR AND evidence of kidney damage. 1, 3
• The provider may have seen the eGFR of 60.6 at the borderline of Stage 2 (60-89) and Stage 3a (45-59) and assumed this automatically warranted a CKD diagnosis. 4, 2

The "60 Threshold" Misconception

• There is widespread confusion about the significance of the 60 mL/min/1.73 m² threshold—this is the cutoff where eGFR alone becomes sufficient for diagnosis, not where CKD begins. 4, 2
• KDOQI and KDIGO have acknowledged that the application of current classification systems leads to over-diagnosis and misdiagnosis of CKD, particularly at borderline eGFR values. 4

Analytical and Biological Uncertainty

• At the critical decision level of 60 mL/min/1.73 m², the uncertainty of eGFR is calculated to be ±11 mL/min/1.73 m², meaning caution is needed when interpreting values between 49-71. 5
• An eGFR of 60.6 could represent normal kidney function, especially if the patient is elderly, female, or has reduced muscle mass—populations known to have higher proportions in the Stage 3 category despite potentially normal kidney function. 4
• Approximately 23% of patients with creatinine-based eGFR 45-59 actually have normal kidney function when confirmed with cystatin C, suggesting similar misclassification may occur at higher eGFR values. 2, 6

The Clinical Consequences of This Error

• Assigning a CKD diagnosis to a patient with normal renal function and absence of kidney damage markers can have negative consequences including insurance issues, unnecessary anxiety, and inappropriate medical interventions. 3
• This type of misdiagnosis contributes to inflated CKD prevalence rates that are disproportionate to actual kidney failure incidence, a concern raised by KDOQI and KDIGO. 4

What Should Have Been Done

• The provider should have specifically looked for markers of kidney damage: albuminuria (≥30 mg/24h), proteinuria, hematuria, pathological abnormalities on biopsy, or imaging abnormalities. 1, 2, 7
• Without any of these markers present for at least 3 months, no CKD diagnosis should have been made regardless of the eGFR value. 1, 2, 3
• If there was concern about the borderline eGFR, the provider could have ordered cystatin C measurement to confirm whether kidney function was truly reduced or if the creatinine-based estimate was inaccurate. 2, 6

Key Pitfall to Avoid

The most common error in CKD diagnosis is equating any abnormal eGFR with CKD without considering whether additional diagnostic criteria are met—this is particularly problematic for eGFR values ≥60 mL/min/1.73 m² where kidney damage markers are mandatory for diagnosis. 1, 3