46. Hematuria

• Personal and family history

  • Kidney disease (e.g., polycystic kidney disease) or renal failure

  • Sickle cell disease

• Medication: e.g., anticoagulants, nephrotoxic agents

• Travel history: especially areas endemic for Schistosoma haematobium or tuberculosis

• Additional urinary symptoms

  • Dysuria (pain, burning, urge to void)

  • Flank pain

  • Difficulty voiding (urine retention, straining, intermittent stream, dribbling)

• Additional nonurinary symptoms

  • Recent or current upper respiratory infection

  • Skin changes (e.g., edema, rashes, petechiae, purpura)

  • Menstruational abnormalities

• Urine dipstick: detects heme in urine (high sensitivity, low specificity)

  • A negative result for heme on urine dipstick makes hematuria very unlikely.

  • A positive result for heme does not confirm hematuria because the test does not distinguish between the presence of RBCs, hemoglobin, and myoglobin.

  • If additional proteinuria is present, evaluate for glomerular diseases.

• Urine sediment: Confirm hematuria with microscopy (≥ 3 RBCs/HPF).

  • If RBC casts and proteinuria are present: Evaluate for glomerular diseases.

  • If the morphology of RBCs is normal: Evaluate for nonglomerular causes (e.g., coagulation disorders, kidney stones, malignancy).

  • Urine that is positive for heme on dipstick but shows no RBCs on microscopy indicates hemoglobinuria or myoglobinuria.

  • In hemoglobinuria and myoglobinuria, the urine remains pigmented after centrifugation because the pigments are dissolved in the urine and do not settle at the bottom like RBCs in hematuria.

Perform if clinical signs of infection exist or dipstick is positive for WBCs (pyuria) and/or leukocyte esterase

• Both conditions cause red, amber, or “Coca-Cola” colored transparent urine that remains pigmented after centrifugation.

• Urine remains pigmented after centrifugation because the pigments are dissolved in the urine and do not settle at the bottom like RBCs in hematuria.

• Asymptomatic microhematuria is less commonly associated with cancer than gross hematuria. [21]

• Patients should be evaluated for glomerular causes (see “Glomerular vs. nonglomerular hematuria”); if present patients should be additionally worked up by nephrology. [23]

• Assessment for urinary tract cancer is based on risk stratification.

• Low risk: either of the following, selected using shared decision-making.

  • Repeat urinalysis within 6 months.

  • OR evaluate with renal bladder ultrasound and refer for cystoscopy.

• Intermediate risk: Order a renal bladder ultrasound and refer for cystoscopy. [23]

• High risk: Order CT urography and refer for cystoscopy.