Macroscopic hematuria is usually the result of an extra-renal manifestation. Isolated hematuria without accompanying proteinuria points towards a urological issue, and urinary tract infection, kidney stones, and tumors must be eliminated as possible causes.
Microscopy can give an indication if the hematuria is caused by a renal or an extra-renal disease. In glomerular hematuria, the erythrocytes are exposed to osmotic and mechanical forces on their way through the nephron causing a dysmorphic appearance. Hematuria with round and uniformly large erythrocytes gives suspicion of extra-renal manifestation. Normal secretion of protein and the absence of casts in the urine sediment should lead to examination for extra-renal causes. Conversely, dysmorphic hematuria (erythrocytes with abnormal form and large variation in size) with casts in the urine sediment is a nephritic sediment and glomerular inflamation should be suspected. If erythrocyte casts are present, then glomerulonephritis is present.
Nephritic syndrome presents with a nephritic sediment, hypertension and falling GFR.
The different types of glomerulonephritis have a tendency to clinically present with either nephrotic or nephritic characteristics. This supports a diagnosis before the biopsy results are acquired.