How can I differentiate between nephrotic syndrome and nephritic syndrome in a primary care setting?

Nephrotic syndrome and nephritic syndrome can be differentiated in primary care primarily through clinical features and basic urine and blood tests.

Nephrotic syndrome typically presents with heavy proteinuria (usually >3.5 g/day), hypoalbuminaemia, significant peripheral oedema, and hyperlipidaemia. Urine dipstick or albumin:creatinine ratio (ACR) testing will show marked proteinuria without significant haematuria. Patients often have minimal or no hypertension and preserved renal function initially ¹.

Nephritic syndrome, in contrast, is characterised by haematuria (often visible or persistent microscopic haematuria), variable proteinuria (usually less than nephrotic range), hypertension, and impaired renal function. Urine testing reveals red blood cell casts and persistent haematuria alongside proteinuria. Patients may present with oedema but less pronounced than in nephrotic syndrome. Blood tests may show elevated creatinine and reduced estimated glomerular filtration rate (eGFR) ¹[(Lamba et al., 2020)].

In primary care, initial differentiation relies on:

• Urine dipstick testing: nephrotic syndrome shows heavy proteinuria with minimal haematuria; nephritic syndrome shows haematuria with or without proteinuria ¹.
• Blood pressure measurement: hypertension is more common and often severe in nephritic syndrome ¹[(Lamba et al., 2020)].
• Serum albumin and lipid profile: hypoalbuminaemia and hyperlipidaemia support nephrotic syndrome diagnosis ¹.
• Renal function tests: nephritic syndrome often shows reduced eGFR and raised creatinine, whereas nephrotic syndrome may have normal or mildly impaired renal function initially ¹.

Referral to nephrology is indicated if nephrotic syndrome is suspected due to the need for further investigation and management, including renal biopsy and specialist treatment ¹. Persistent haematuria with proteinuria or declining renal function also warrants specialist assessment ¹[(Lamba et al., 2020)].