Hematuria

Hematuria — blood in the urine — is classified as gross (visible) hematuria, blood visible to the naked eye ranging from a faint pink tinge to frank, clot-laden blood, or microscopic (non-visible) hematuria, detected only on urine dipstick or laboratory microscopy. Current guidance defines significant microscopic hematuria as ≥3 red blood cells per high-power field (RBC/HPF) on microscopic evaluation of a single, properly collected urine specimen — a positive dipstick alone, no matter how strongly positive, is never sufficient on its own to diagnose hematuria or to trigger a full workup; it must first be confirmed by laboratory microscopy.^[1][2]

Gross (visible) hematuria — even a small volume of blood visibly discolours urine; this specimen followed trauma. Visible hematuria at any age always warrants full urologic evaluation. (James Heilman, MD; CC BY-SA 4.0, Wikimedia Commons)

Hematuria is common — population screening studies report a prevalence of microscopic hematuria ranging from 2.4% to 31.1%, depending on the population studied and the threshold used.^[2] The great majority of cases have a benign or self-limited explanation, but hematuria is a sign, not a diagnosis: it may be associated with an underlying urologic malignancy in up to 10% of cases,^[2] and the entire purpose of a structured workup is to reliably separate that minority from the many transient or benign causes without over-testing everyone. The single most important framing point for pharmacists, returned to throughout this chapter: hematuria in a patient taking an anticoagulant or antiplatelet agent still needs the same evaluation as hematuria in anyone else — patients on a DOAC or warfarin very reasonably, but often incorrectly, assume their medication fully explains the bleeding.^[1][2]

Benign, transient causes — common, and worth actively ruling out

A meaningful share of positive dipsticks, and even some confirmed microscopic hematuria, resolve completely once a transient contributing factor is addressed. Guidance is explicit that these should be actively assessed for and, where present, retested after resolution — before further workup begins, not instead of it if hematuria persists.^[2]

• Urinary tract infection — the most common benign explanation; confirm with urine culture, treat, and re-test the urinalysis with microscopy after treatment to document that the hematuria itself has actually resolved — it cannot simply be assumed to have resolved along with the infection.^[1]
• Menstrual or vaginal contamination — repeat a midstream, clean-catch specimen once menses has ended if contamination is possible.^[2]
• Vigorous exercise ("athletic" or exercise-induced hematuria) — typically resolves within 48-72 hours of rest; retest after abstaining from strenuous activity.^[2]
• Recent urethral trauma, sexual activity, or urologic instrumentation/catheterization — retest once the precipitating event is well in the past.^[2]
• A recent viral illness.^[2]

Causes that genuinely need investigation

Painless gross hematuria deserves special emphasis: it is the single most classic presenting sign of bladder cancer, and the absence of pain does not make it less concerning — closer to the opposite is true. Do not let a single episode that stops spontaneously be dismissed as resolved; it still requires full evaluation (see Red Flags & Refer and Choose Initial Treatment).^[2]

Not all red urine is hematuria — and not all hematuria is visibly red

See Assessment & Diagnosis for the specific pitfalls of dipstick testing, including beeturia, myoglobinuria, high-dose vitamin C, and drug-induced urine discoloration.

The panel that developed the current AUA/SUFU microhematuria guideline defined a specific set of factors built directly into its risk-stratification system, alongside a broader list of additional recognized risk factors for urothelial cancer.^[1]

Smoking is the single strongest risk factor for bladder cancer.^[2] Occupations reported at higher risk include tobacco workers, dye and textile workers, chimney sweeps, nurses, rubber workers, waiters, metal workers, electricians, mechanics, military and public safety personnel, domestic and cleaning staff, hairdressers, painters, printers, seafarers, oil and petroleum workers, shoe and leather workers, plumbers, truck drivers, drill press operators, chemical workers, and roofers/coal tar workers.^[2] Additional recognized risk factors include a personal history of bladder cancer, overuse of analgesic drugs (historically phenacetin-containing analgesics), and — exceedingly rare in North America but endemic to the Middle East and Africa — Schistosoma haematobium infection.^[2][3]

Confirming hematuria: dipstick is a screen, microscopy is the diagnosis

Urine dipstick testing detects the peroxidase-like activity of hemoglobin and is a sensitive screening test, but it does not reliably distinguish true red blood cells from free hemoglobin (hemolyzed blood) or myoglobin, and it can be falsely negative or positive for genuine, common reasons (see the table below). A positive dipstick (trace blood or greater) should prompt formal microscopic evaluation; it must never be used alone to diagnose hematuria or to trigger a full evaluation.^[1]

Confirm significant microscopic hematuria as ≥3 RBC/HPF on microscopic evaluation of a properly collected specimen; 0-2 RBC/HPF is insignificant and does not warrant further investigation unless clinical suspicion remains high, in which case a repeat test showing ≥3 RBC/HPF should trigger the workup below.^[1][2] A single positive microscopy is sufficient to initiate workup — hematuria is known to be highly intermittent even in the presence of significant underlying pathology, so waiting for a second confirmatory result before acting is not appropriate practice.^[2]

Specimen collection matters. Use a midstream, clean-catch specimen. The sample for microscopy must be examined fresh, within 2-3 hours of collection — in practice this means sending the patient to a laboratory rather than relying on a specimen that has sat for hours beforehand.^[2] If contamination by menstrual blood or vaginal discharge is possible, repeat the sample once resolved.^[2]

A urine dipstick being read — the blood/heme pad is one of several colour-reactive pads. A positive result must be confirmed with laboratory microscopy before diagnosing hematuria. (Spicy; CC BY-SA 4.0, Wikimedia Commons)

Pitfalls: what looks like hematuria but isn't, and what hides true hematuria

Differentiating a glomerular from a non-glomerular source

Once significant microscopic hematuria (or gross hematuria) is confirmed, examine the same specimen for evidence of a glomerular (medical renal) cause, and measure serum creatinine/eGFR, urine albumin-to-creatinine ratio (ACR), and blood pressure in every patient.^[1][2] Dysmorphic RBCs on microscopy, red cell casts, proteinuria (urine ACR over 30 mg/mmol), or an abnormal/declining creatinine or eGFR and new hypertension all suggest a glomerular cause and should prompt nephrology referral — this does not replace risk-based urologic evaluation, which should still proceed in parallel rather than being deferred.^[1]

Risk stratification for genitourinary malignancy

Once a glomerular cause has been excluded (or is being managed in parallel), categorize every patient with confirmed significant microscopic hematuria as low-, intermediate-, or high-risk for genitourinary malignancy.^[1]

^[1]

Imaging and cystoscopy by risk category

Kidney/bladder ultrasound is the preferred, first-choice imaging test in most circumstances given its safety (no ionizing radiation, no contrast), availability, and lower cost — reserve CT or MR urography for high-risk patients or those with visible hematuria and/or strong risk factors, where superior upper-tract urothelial detection is needed.^[3][2] A family history of renal cell carcinoma or a known genetic renal tumour syndrome warrants upper-tract imaging regardless of calculated risk category.^[1]

Urine cytology and urinary markers

Do not use urine cytology or urine-based tumour markers in the initial evaluation of asymptomatic microscopic hematuria — they are poor screening tests in this setting.^[1] Cytology has a legitimate, separate role: it is appropriate for gross hematuria and for symptomatic microscopic hematuria (once modifiable causes have been excluded), and it may be obtained for persistent microscopic hematuria after a negative workup in a patient with irritative voiding symptoms or risk factors for carcinoma in situ.^[1][2]

The anticoagulated or antiplatelet patient

Perform the identical evaluation in a patient taking an antiplatelet agent or anticoagulant — aspirin, another antiplatelet, a DOAC, or warfarin, regardless of type or dose — as in a patient not on these agents.^[1][2] Anticoagulation predisposes to hematuria only in the presence of underlying urinary tract disease; it does not cause hematuria on its own in a genitourinary tract that is otherwise normal.^[2] A population-based Ontario cohort found that patients newly exposed to antithrombotic medication were significantly more likely to be diagnosed with bladder cancer within 6 months than unexposed patients — consistent with anticoagulation unmasking bleeding from a pre-existing lesion rather than causing it outright — and a 2025 emergency-department cohort confirmed that anticoagulant/antiplatelet therapy can provoke gross hematuria that goes on to reveal an underlying urologic malignancy.^[1][6] Do not dismiss microscopic hematuria in an anticoagulated patient as an expected medication effect.

• Reliably separate patients who need urgent or expedited urologic/nephrology evaluation from the larger group who can be safely managed with reassurance, resolution of a transient cause, or a defined follow-up interval.
• Recognize and manage hematuria-related emergencies — clot retention, hemodynamic instability, an obstructed and infected upper tract — the same day they present.
• Confirm every episode of significant microscopic hematuria with laboratory microscopy, never dipstick alone, before committing a patient to further workup.
• Differentiate a glomerular (medical renal) source from a urologic one, and refer to the correct specialty — sometimes both in parallel.
• Apply the identical, unbiased evaluation to a patient on an anticoagulant or antiplatelet agent as to any other patient, rather than assuming the medication explains the finding.
• Avoid unnecessary radiation, contrast exposure, and invasive testing in genuinely low-risk patients, while never under-evaluating a patient with real risk factors.
• Set realistic expectations and a concrete follow-up plan for the many patients whose workup will be negative.

• Clot retention — place a large-bore (generally at least 22 Fr) urethral catheter and manually irrigate the bladder with 0.9% saline via a catheter-tipped syringe to evacuate clots and restore drainage; most patients then need a continuous-irrigation ("3-way") catheter to keep the bladder clear while the source is addressed. If clots cannot be cleared by hand irrigation, cystoscopy and clot evacuation in the operative setting is required.
• Correct hemodynamic instability with standard resuscitation (IV access, fluids, transfusion as indicated) before or alongside definitive source control.
• Specimen technique — collect a midstream, clean-catch sample; have the patient go to the laboratory so the specimen for microscopy can be examined fresh, within 2-3 hours; use the same laboratory for follow-up testing to keep results comparable.^[2]
• For suspected exercise-induced hematuria, advise rest from strenuous activity before retesting; for suspected menstrual contamination, repeat once menses has ended.^[2]
• Advise a patient taking high-dose vitamin C or a vitamin-C-rich supplement that it can mask a truly positive dipstick — this is a reason to proceed to microscopy when suspicion remains, not a reason to stop a supplement the patient otherwise wants to take.^[5]
• Reassure a patient with confirmed beeturia (red-pink urine after beets, with a negative dipstick) that this is not hematuria — but note that persistent beeturia can be a clue to check for iron deficiency.^[4]
• Screening the general population for microscopic hematuria (by dipstick or microscopy) is not currently recommended, given insufficient evidence of net benefit.^[2]
• Cystoscopy and imaging are themselves the definitive diagnostic procedures for urologic causes — there is no pharmacologic substitute for them once evaluation is indicated.

Pregnancy

Hematuria in pregnancy shares much of the same differential as in non-pregnant patients (UTI is especially common in pregnancy), but proteinuria plus hematuria in the second half of pregnancy must also prompt evaluation for preeclampsia — do not assume a urologic cause without checking blood pressure and screening for preeclampsia features (see the Preeclampsia chapter). Imaging ultrasound is preferred throughout pregnancy to avoid ionizing radiation; defer CT urography unless the clinical situation is urgent enough that the diagnostic benefit clearly outweighs fetal radiation exposure, and make any such decision together with obstetrics and urology. Treat a confirmed UTI promptly (see the Urinary Tract Infection chapter for pregnancy-specific regimens) and re-test to confirm resolution of the hematuria.

Pediatrics

The differential in children differs meaningfully from adults: malignancy is rare, and the more common significant causes are post-infectious (post-streptococcal) glomerulonephritis (typically 1-3 weeks after a streptococcal throat or skin infection, often with edema, hypertension, and cola-coloured urine), IgA nephropathy, idiopathic hypercalciuria (a common cause of isolated, otherwise-unexplained microscopic hematuria in children), and benign familial hematuria (thin basement membrane nephropathy). Gross hematuria, hypertension, edema, or any evidence of a glomerular pattern in a child warrants prompt pediatric nephrology referral rather than a routine adult-style urologic workup.

Older adults

Age is itself a major risk factor in every risk-stratification system in this chapter — malignancy risk rises with age, and any hematuria in a patient 60 or older is automatically high-risk regardless of other factors (see Assessment & Diagnosis). Maintain a low threshold for full evaluation, and do not attribute hematuria to "old age" or a chronic catheter without still investigating.

Anticoagulated patients (DOACs and warfarin) — the key counselling point for pharmacists

Patients taking a DOAC or warfarin very commonly, and often confidently, attribute any hematuria entirely to their anticoagulant. This is a genuine, high-value counselling opportunity: explain clearly that anticoagulation does not cause hematuria in an otherwise normal urinary tract — it can only worsen bleeding from a lesion that is already there, and that current guidance requires the identical risk-based evaluation regardless of anticoagulant type, dose, or level of therapy.^[1][2] Do not counsel a patient to stop their anticoagulant on their own, and do not imply to a patient that stopping it will "fix" the hematuria — that decision belongs to the prescriber, weighed against the patient's stroke or VTE risk, and is separate from the hematuria workup itself. See Choose Initial Treatment and Drug Tables.

Renal impairment / chronic kidney disease

Hematuria and CKD frequently overlap — a patient with known CKD who develops new or worsening hematuria still needs the glomerular-versus-urologic differentiation above, and a new finding of proteinuria or a meaningful eGFR decline should prompt nephrology involvement per the Chronic Kidney Disease chapter, in parallel with any indicated urologic evaluation.

When no specific cause is found after a complete initial evaluation, follow the patient annually — this is not optional reassurance-only follow-up, since a small proportion of patients with an initially negative workup are later diagnosed with a urologic malignancy.^[2][7]

• Annual urine microscopy, urine albumin-to-creatinine ratio, serum creatinine/eGFR, and blood pressure.
• Annual urine cytology only in patients with risk factors for urothelial cancer — not routinely in every patient.^[2]
• If, after the initial evaluation, the degree of microscopic hematuria persists unchanged on annual follow-up, consider repeat investigation within 3-5 years.^[2]
• If three consecutive annual urine microscopies are negative, follow-up testing for that episode can be discontinued.^[2]
• Trigger immediate re-investigation, rather than waiting for the next scheduled annual visit, if the patient develops gross hematuria, new urinary symptoms, an increasing degree of microscopic hematuria, new or worsening proteinuria, or declining renal function.^[2]

1. Negative cystoscopy and imaging but persistent, unchanged microscopic hematuria and high clinical suspicion: consider referral for a more detailed upper-tract evaluation (for example, ureteroscopy or selective ureteral washings) rather than simply repeating the same negative tests.
2. New gross hematuria, new urinary symptoms, an increasing degree of microscopic hematuria, new proteinuria, or declining renal function after a prior negative workup: re-investigate immediately rather than waiting for the next annual visit.^[2]
3. A low-risk patient who chose repeat urinalysis at 6 months and is still found to have significant microscopic hematuria: reclassify as intermediate- or high-risk and proceed to cystoscopy and the matched imaging study — do not simply repeat the urinalysis again.^[1]
4. Hematuria persisting despite treatment of an identified benign cause (for example, a UTI, once repeat culture and urinalysis confirm the infection itself has resolved): proceed with risk-based urologic evaluation rather than assuming the original cause explains everything.^[1]
5. Recurrent hematuria in an anticoagulated patient despite a negative urologic and nephrology workup: reassess whether the anticoagulant intensity or agent is appropriate for the patient's current renal function and bleeding risk, in consultation with the prescriber — but only after, not instead of, completing the standard evaluation.
6. Ongoing clot retention despite catheter irrigation: proceed to cystoscopy and operative clot evacuation rather than prolonging attempts at bedside irrigation.

• Diagnosing or ruling out hematuria from a dipstick result alone, without confirmatory microscopy.
• Attributing hematuria in an anticoagulated or antiplatelet patient to the medication without performing the same risk-based evaluation used for any other patient.
• Advising or allowing a patient to stop their anticoagulant on their own initiative because of hematuria, rather than involving the prescriber.
• Ordering urine cytology or a urine-based tumour marker as part of the initial evaluation of asymptomatic microscopic hematuria.
• Missing beeturia, myoglobinuria, high-dose vitamin C, or a discoloring drug (phenazopyridine, rifampin) as an explanation for visually red urine or an unexpected dipstick result.
• Failing to repeat testing after a genuinely modifiable cause (infection, menstruation, exercise, recent instrumentation) has resolved, before either committing to or abandoning further workup.
• Treating a single, brief episode of visible gross hematuria that has since stopped as resolved and not requiring referral.
• Finding dysmorphic RBCs, red cell casts, or proteinuria and referring only to nephrology, or only to urology, instead of pursuing both in parallel where indicated.
• Assuming a young patient's hematuria cannot be malignant when meaningful risk factors (a heavy smoking history, occupational exposure, pelvic radiation, cyclophosphamide exposure) are present.
• Discontinuing annual follow-up before three consecutive negative annual tests, or discontinuing it entirely without checking whether the degree of persistent hematuria has changed.
• Missing clot retention as a same-day emergency, or attempting prolonged bedside management when clots cannot be cleared by hand irrigation.
• Prescribing phenazopyridine before a pending hematuria specimen has been collected, or continuing it beyond 2 days.

How to use this table: hematuria itself does not have a drug "treatment" — these tables cover genuine adjuncts (tranexamic acid, phenazopyridine), commonly confused drug-induced urine discoloration, and how anticoagulants and UTI antibiotics are handled during a hematuria workup. Doses are adult doses and require patient-specific confirmation, including renal/hepatic adjustment. Select any drug name to open its complete Pharmasist Drug Database page.

Antifibrinolytic for gross hematuria or clot-forming bleeding

Specialist (urology)-directed; not a first step taken independently for microscopic hematuria.

Short-term symptomatic relief (does not treat the underlying cause)

Other drugs that discolour urine without causing true hematuria

Included as a teaching reference — none of these require dose adjustment for hematuria, since they are not its cause.

Anticoagulants and antiplatelet agents found incidentally at the time of a hematuria workup

None of these are started, stopped, or dose-adjusted because of hematuria alone — that decision belongs to the prescriber, weighed against the patient's thrombotic risk, and is separate from completing the standard hematuria evaluation. Full dosing is in the Atrial Fibrillation and Venous Thromboembolism chapters.

Empiric antibiotics when hematuria is attributed to a confirmed urinary tract infection

Full dosing, duration, and pregnancy-specific regimens are in the Urinary Tract Infection chapter. Whichever agent is used, re-test the urinalysis with microscopy after treatment to confirm the hematuria has actually resolved — resolution of infection does not guarantee resolution of hematuria.