NephrologyTier 2Topic

Laboratory tests - haematuria

Definition and localisation

Blood in the urine - visible (macroscopic) or non-visible (microscopic, detected on dipstick/microscopy) - always requires a cause to be sought, though the urgency and pathway differ
Localises broadly to glomerular (dysmorphic red cells, red cell casts, associated proteinuria) vs non-glomerular/urological (isolated, normal-shaped red cells) sources

Visible haematuria has a substantially higher rate of underlying malignancy than non-visible haematuria and is investigated more urgently

Glomerular causes: IgA nephropathy (the commonest cause of glomerular haematuria), thin basement membrane disease, Alport syndrome, glomerulonephritis
Non-glomerular causes: stones, UTI, malignancy (urothelial/renal/bladder/prostate), BPH, trauma, exercise-induced (transient, benign); anticoagulation does not itself cause haematuria - it unmasks an underlying lesion and still requires investigation

Urine microscopy - dysmorphic red cells and/or red cell casts point to a glomerular source; normal-shaped cells with no casts point to a urological source
Visible haematuria, or non-visible haematuria with risk factors (age, smoking, occupational exposure) -> urological pathway: CT urogram + cystoscopy
Non-visible haematuria with proteinuria, hypertension, or reduced eGFR -> nephrological pathway: consider renal biopsy if glomerulonephritis is suspected

Isolated transient microscopic haematuria (e.g. post-exercise) with a normal workup - reassurance and no further action
Persistent haematuria - follow the glomerular vs urological pathway above to the relevant specialist

IgA nephropathy, urothelial carcinoma, nephrolithiasis, BPH, exercise-induced haematuria (benign, transient)

Isolated non-visible haematuria with a fully negative workup carries a low but not zero long-term risk and is generally followed with periodic urinalysis rather than repeated invasive investigation

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