When to Rule Out CKD in Adults
Screen for CKD immediately in all adults with diabetes, hypertension, age >60 years, family history of kidney disease, cardiovascular disease, or obesity using both eGFR and UACR—these populations require active case-finding rather than "ruling out" CKD. 1, 2
Risk-Based Screening Approach
High-Priority Populations Requiring Immediate Screening
All patients with diabetes must be screened annually starting at diagnosis for type 2 diabetes (not after 10 years), as 6.5% already have significant albuminuria and 28% have hypertension at diagnosis. 2
All patients with hypertension should be screened during chronic disease management, as 91% of CKD patients have hypertension and the combination dramatically accelerates kidney damage. 1
Additional mandatory screening groups include: 1, 2
- Adults age >60 years (prevalence increases substantially with age)
- Family history of kidney disease or kidney failure (strong independent risk factor)
- Cardiovascular disease (46% of CKD patients have atherosclerotic heart disease)
- Obesity (metabolic syndrome phenotype accelerates CKD)
- African American race (3-5 times higher risk of end-stage renal disease)
Appropriate Screening Tests
Measure both eGFR (calculated from serum creatinine using CKD-EPI equation) AND urinary albumin-to-creatinine ratio (UACR) on a random spot urine sample—never use urine dipstick alone or rely on serum creatinine without calculating eGFR. 1, 2, 3
CKD is diagnosed when either abnormality persists ≥3 months: 2, 3
- eGFR <60 mL/min/1.73 m² (stages 3-5), OR
- UACR ≥30 mg/g (with any eGFR, including normal)
When NOT to Screen (Low-Yield Populations)
Routine screening is NOT recommended for asymptomatic adults without risk factors—the USPSTF found insufficient evidence for universal screening, as the risk of CKD and subsequent adverse outcomes is small in this population. 1
For adults without diabetes or hypertension: 1
- No studies demonstrate benefits of early treatment
- Risk of false positives leading to unnecessary interventions
- Potential harms from medications without proven benefit
Confirmation Requirements Before Diagnosing CKD
Never diagnose CKD based on a single abnormal test—both eGFR <60 mL/min/1.73 m² and UACR ≥30 mg/g must persist for ≥3 months to distinguish CKD from acute kidney injury or transient proteinuria. 2, 3, 4
Repeat testing within 2-4 weeks if: 2
- Initial abnormality detected but duration unclear
- Need to distinguish acute kidney injury from CKD
- Recent medication changes affecting kidney function
Common Pitfalls to Avoid
Do not skip albuminuria testing—approximately 20-40% of CKD patients have reduced eGFR without albuminuria, and conversely, patients can have significant albuminuria with normal eGFR (stages 1-2 CKD). Both provide independent prognostic information. 2, 3
Do not rely on serum creatinine alone—always calculate eGFR using validated equations (CKD-EPI 2021), as creatinine levels vary by age, sex, muscle mass, and race. 2, 3, 4
Do not use urine dipstick for screening—UACR measurement is required for accurate quantification and risk stratification. 2
Monitoring Frequency After Initial Screening
For confirmed CKD, monitoring frequency depends on stage and albuminuria category: 3, 4
- Stage 2 (eGFR 60-89) with UACR <30 mg/g: annually
- Stage 3a (eGFR 45-59): every 6-12 months
- Stage 3b (eGFR 30-44): every 6-12 months
- Stage 4 (eGFR 15-29): every 3-5 months
- Stage 5 (eGFR <15): every 1-3 months
Increase monitoring frequency to 2-4 times per year when UACR ≥30 mg/g regardless of eGFR. 3
When to Refer to Nephrology
Immediate nephrology referral is indicated for: 2, 3, 4
- eGFR <30 mL/min/1.73 m² (stage 4-5 CKD)
- Continuously increasing albuminuria despite optimal management
- Rapidly declining eGFR (>20% decline on subsequent testing)
- UACR >300 mg/g with difficulty managing complications
- Uncertainty about etiology or atypical features suggesting non-diabetic kidney disease