Diagnosis: Stage 3a Chronic Kidney Disease
A GFR of 56 mL/min/1.73 m² definitively indicates Stage 3a chronic kidney disease (CKD), regardless of whether other laboratory values appear normal. 1, 2
Understanding Your Diagnosis
Stage 3a CKD is defined as GFR 45-59 mL/min/1.73 m², representing moderate reduction in kidney function with loss of approximately half of normal adult kidney function. 1
This diagnosis requires that the reduced GFR has been present for at least 3 months to distinguish it from acute kidney injury. 1
At this stage, the prevalence of CKD complications begins to rise significantly, including anemia, bone disease, malnutrition, and cardiovascular disease risk. 1
Immediate Next Steps
1. Complete CKD Staging with Albuminuria Assessment
Measure urine albumin-to-creatinine ratio (UACR) on a spot urine sample immediately to complete your CKD staging and determine treatment intensity. 2, 3
Normal UACR is <30 mg/g; moderate albuminuria (A2) is 30-299 mg/g; severe albuminuria (A3) is ≥300 mg/g. 2
2. Identify the Underlying Cause
- Evaluate for diabetes, hypertension, glomerular disease, vascular disease, tubulointerstitial disease, or cystic kidney disease through history, physical examination focusing on blood pressure and edema, urinalysis for proteinuria and hematuria, and renal ultrasound if etiology is unclear. 1, 3
Management Algorithm Based on Albuminuria
If UACR <30 mg/g (No Albuminuria):
Monitor GFR and UACR twice yearly (every 6 months). 2
Target blood pressure <130/80 mmHg using any antihypertensive class. 2
Focus on cardiovascular risk reduction with statin therapy and lifestyle modifications including sodium restriction, regular physical activity, smoking cessation, and weight management. 4, 2, 3
Avoid nephrotoxins, particularly NSAIDs. 3
If UACR 30-299 mg/g (Moderate Albuminuria):
Initiate ACE inhibitor or ARB therapy immediately, even if blood pressure is normal, as these medications reduce albuminuria and slow CKD progression. 2, 3
Monitor GFR and UACR twice yearly. 2
Consider SGLT2 inhibitor if you have type 2 diabetes and UACR ≥200 mg/g. 2
Monitor potassium levels within 1-2 weeks after starting ACE inhibitor/ARB. 2
If UACR ≥300 mg/g (Severe Albuminuria):
Strongly recommend ACE inhibitor or ARB therapy. 2
Refer to nephrology for co-management. 2
Monitor GFR and UACR 2-3 times yearly (every 4-6 months). 2
Monitoring Requirements at Stage 3a
Check eGFR, serum creatinine, UACR, blood pressure, and electrolytes (especially potassium if on ACE inhibitor/ARB) twice yearly. 2
Screen for CKD complications including anemia (hemoglobin), bone disease (calcium, phosphorus, PTH, vitamin D), and metabolic acidosis (serum bicarbonate). 1, 3
When to Refer to Nephrology
Refer to nephrology if any of the following are present: 2, 3
- UACR ≥300 mg/g
- Rapid GFR decline (>5 mL/min/1.73 m² per year)
- Uncertain etiology of kidney disease
- Refractory hypertension despite multiple medications
- Persistent electrolyte abnormalities (hyperkalemia, metabolic acidosis)
- Active urine sediment (hematuria with proteinuria)
Mandatory nephrology referral occurs when GFR declines to <30 mL/min/1.73 m² (Stage 4 CKD) to prepare for potential kidney replacement therapy. 1, 2
Critical Pitfalls to Avoid
Do not assume normal kidney function based on normal serum creatinine alone, as creatinine may remain in the normal range until significant kidney function is lost, particularly in elderly patients or those with low muscle mass. 1
Do not use NSAIDs (ibuprofen, naproxen), as they can accelerate kidney function decline. 3
Adjust medication dosing for renally cleared drugs including many antibiotics, oral hypoglycemic agents, and anticoagulants. 1, 3
Avoid contrast dye procedures without adequate hydration protocols and consideration of alternative imaging when possible. 3