What testing is recommended for a patient with type 2 diabetes (T2D) and a recent decline in estimated Glomerular Filtration Rate (eGFR) from normal to impaired renal function?

Recommended Testing for Elderly Female with Type 2 Diabetes and Declining eGFR

This patient requires immediate confirmation of chronic kidney disease through repeat eGFR measurement and urinary albumin-to-creatinine ratio (UACR) testing, followed by systematic evaluation for CKD complications and underlying causes. 1

Confirm CKD Diagnosis and Establish Chronicity

• Repeat serum creatinine and eGFR within 2-4 weeks to confirm the decline represents chronic kidney disease rather than acute kidney injury, as CKD requires persistence of abnormalities for at least 3 months 1, 2
• Measure UACR on a random spot urine sample immediately (preferably early morning), as this is essential for risk stratification, treatment decisions, and CKD diagnosis even when eGFR is reduced 1, 2
• Review all historical eGFR values to determine the rate and pattern of decline, as rapid eGFR decline (>5 mL/min/1.73 m² per year) indicates higher risk and may warrant earlier nephrology referral 3

Essential Baseline Laboratory Testing

Complete metabolic panel including 1, 2:

• Serum electrolytes (sodium, potassium, chloride, bicarbonate) to screen for metabolic acidosis and hyperkalemia
• Blood urea nitrogen and creatinine
• Glucose and HbA1c for glycemic control assessment

CKD complication screening (required at eGFR <60 mL/min/1.73 m²) 1, 2:

• Complete blood count to assess for anemia
• Serum calcium and phosphate
• Intact parathyroid hormone (PTH), as secondary hyperparathyroidism begins when eGFR falls below 60 mL/min/1.73 m²
• 25-hydroxyvitamin D level
• Lipid panel for cardiovascular risk assessment

Urinalysis with microscopy to evaluate for 1, 2:

• Hematuria (particularly red cell casts suggesting glomerulonephritis)
• Pyuria indicating infection or interstitial disease
• Active sediment that might suggest non-diabetic kidney disease

Determine Underlying Etiology

While diabetic kidney disease is the most likely diagnosis given her type 2 diabetes history, atypical features warrant additional investigation 1:

• Absence of diabetic retinopathy on dilated eye examination suggests possible non-diabetic kidney disease, as retinopathy is typically present in diabetic kidney disease 1
• Rapid eGFR decline (37 mL/min/1.73 m² drop) over an unspecified timeframe raises concern for alternative or superimposed kidney disease 1
• Review medication history for nephrotoxic exposures including NSAIDs, lithium, calcineurin inhibitors, and aminoglycosides 2
• Assess family history of polycystic kidney disease, autoimmune disorders, and hereditary kidney diseases 1, 2

Consider renal ultrasound to assess 1:

• Kidney size and cortical thickness (small kidneys suggest chronicity; normal-sized kidneys can occur in diabetic kidney disease)
• Presence of obstruction, stones, or structural abnormalities
• Corticomedullary differentiation

Risk Stratification Based on UACR Results

The combination of eGFR 58 mL/min/1.73 m² (Stage 3a CKD) and UACR determines progression risk and monitoring intensity 1:

• If UACR <30 mg/g (normal): Moderate risk; monitor eGFR and UACR every 6 months 1, 2
• If UACR 30-300 mg/g (moderately increased): High risk; monitor every 4 months and intensify treatment 1
• If UACR >300 mg/g (severely increased): Very high risk; monitor every 3 months and strongly consider nephrology referral 1

Indications for Nephrology Referral

Refer to nephrology if any of the following are present 1, 2:

• Uncertainty about kidney disease etiology (absence of retinopathy, active urine sediment, rapid decline)
• eGFR <30 mL/min/1.73 m² (though this patient is currently at 58)
• UACR ≥300 mg/g with progressive increase despite optimal therapy
• Difficult management of CKD complications (anemia, mineral bone disease, resistant hypertension, persistent hyperkalemia)
• Abrupt and sustained eGFR decline >5 mL/min/1.73 m² per year
• Persistent hematuria with red cell casts
• Hypertension refractory to 4 or more antihypertensive agents

Common Pitfalls to Avoid

• Do not rely on serum creatinine alone—always calculate eGFR using validated equations (CKD-EPI 2021 is preferred) 1, 2
• Do not skip albuminuria testing—eGFR and UACR provide independent prognostic information for cardiovascular events, CKD progression, and mortality 1, 4
• Do not assume diabetic kidney disease without confirming typical features—up to 30% of patients with diabetes and CKD have alternative diagnoses on kidney biopsy 2
• Do not delay screening for CKD complications—anemia, bone disease, and electrolyte abnormalities should be identified early at this level of kidney function 1

Monitoring Frequency Going Forward

Based on the eGFR of 58 mL/min/1.73 m² (Stage 3a), monitoring frequency should be determined by albuminuria status 1:

• Low risk (UACR <30): Annual to biannual monitoring
• Moderate risk (UACR 30-300): Every 4-6 months
• High risk (UACR >300): Every 3-4 months with nephrology co-management

The rapid decline from 95 to 58 suggests this patient may have experienced either acute-on-chronic kidney injury or represents a fast progressor requiring more intensive monitoring than standard recommendations 3.