How should I monitor renal function and proteinuria in patients diagnosed with glomerulonephritis?

Monitoring renal function in patients with glomerulonephritis involves regular assessment of estimated glomerular filtration rate (eGFR) using serum creatinine, with caution interpreting values in extremes of muscle mass. Confirm eGFR results below 60 ml/min/1.73 m2 by repeating the test within 2 weeks to account for biological variability. Consider referral to nephrology if there is accelerated CKD progression (e.g., sustained eGFR decrease of ≥25% within 12 months and a change in CKD category) or if the 5-year risk of renal replacement therapy exceeds 5% ¹,³.

Proteinuria monitoring should be performed using urine albumin:creatinine ratio (ACR) rather than protein:creatinine ratio (PCR) due to greater sensitivity for low levels of proteinuria. Initial detection requires an ACR test, with confirmation by a repeat early morning sample if ACR is between 3 mg/mmol and 70 mg/mmol; no repeat is needed if ACR is ≥70 mg/mmol. Persistent proteinuria with ACR ≥3 mg/mmol is clinically significant and warrants monitoring and management ¹,².

For adults with persistent proteinuria but without diabetes, refer for nephrology assessment and offer ACE inhibitors or ARBs if ACR is ≥70 mg/mmol. If ACR is 30–70 mg/mmol, monitor and consider specialist advice. In patients with diabetes, offer ACE inhibitors or ARBs if ACR is ≥3 mg/mmol and optimize glycaemic control ²,³.

Monitoring frequency should be individualized based on disease severity and progression risk, agreed with the patient. Additionally, monitor blood pressure and consider testing for haematuria, as persistent haematuria may require further investigation ¹.