# Hematuria Evaluation in Primary Care

## Introduction

Hematuria is a common finding in primary care, detected either as visible (gross) hematuria or incidentally on urinalysis as microscopic hematuria. While most causes are benign, hematuria can be the presenting sign of urologic malignancy, making systematic evaluation essential. The AUA updated its guidelines in 2020 to provide a risk-stratified approach.

## Definitions

Microscopic hematuria is defined as 3 or more red blood cells per high-power field (RBC/HPF) on a properly collected urine specimen. Gross (visible) hematuria is urine visibly discolored by blood and always warrants full urologic evaluation. A single positive urinalysis with 3 or more RBC/HPF is sufficient to initiate evaluation; repeat testing to confirm is not required. A dipstick-positive result for blood without microscopic confirmation of RBCs may represent myoglobinuria or hemoglobinuria rather than true hematuria.

## Common Causes

### Benign Causes

Urinary tract infection is the most common cause of transient hematuria and should be treated, with urinalysis repeated after resolution. Vigorous exercise can cause exercise-induced hematuria that typically resolves within 72 hours. Menstrual contamination should be considered, with urinalysis repeated after menses if uncertain. Benign prostatic hyperplasia and kidney stones are additional common benign causes.

### Serious Causes

Bladder cancer is the most common malignancy presenting with hematuria, especially gross hematuria in adults over 40. Renal cell carcinoma and upper tract urothelial carcinoma are other malignant causes. Prostate cancer less commonly presents with hematuria. Glomerulonephritis, suggested by dysmorphic RBCs, RBC casts, and proteinuria, indicates a nephrologic (glomerular) cause.

## Risk Stratification (AUA 2020)

| Risk Category | Patient Characteristics | RBC/HPF | Recommended Workup |
|--------------|------------------------|---------|-------------------|
| Low | Women <40 or men <25; <10 pack-years; no prior hematuria | 3-10 | Repeat UA in 6 months |
| Intermediate | Women 40-59 or men 25-59; 10-30 pack-years; or persistent low-risk | 11-25 | Cystoscopy + renal ultrasound |
| High | Age ≥60; >30 pack-years; or gross hematuria | >25 | Cystoscopy + CT urography |

### Low Risk

Low-risk patients include women under 40 or men under 25 who have never smoked or have less than 10 pack-years of smoking history, with 3 to 10 RBC/HPF on a single urinalysis and no prior hematuria. The recommendation is to repeat urinalysis in 6 months; if negative, no further workup is needed, and if persistent, the risk category is upgraded.

### Intermediate Risk

Intermediate-risk patients include women aged 40 to 59 or men aged 25 to 59, those with 10 to 30 pack-years of smoking history, 11 to 25 RBC/HPF, or prior low-risk evaluation with persistent hematuria. The recommendation is cystoscopy and renal ultrasound.

### High Risk

High-risk patients include those aged 60 or older, those with more than 30 pack-years of smoking history, more than 25 RBC/HPF, or a history of gross hematuria. The recommendation is cystoscopy and CT urography for axial imaging of the upper tracts.

![Risk stratification table for microscopic hematuria evaluation per AUA 2020 guidelines](images/hematuria-risk-stratification.jpg)

## Evaluation Workup

### Initial Assessment

Urinalysis with microscopy confirms 3 or more RBC/HPF and assesses for proteinuria, pyuria, and casts. Urine culture rules out UTI; if positive, the infection is treated and urinalysis repeated after resolution. Serum creatinine assesses baseline renal function. History should explore smoking, occupational exposures (dyes, chemicals), prior radiation, cyclophosphamide use, and family history of renal disease or urologic cancer.

### Nephrology Referral Indicators

Nephrology referral is indicated when dysmorphic RBCs or RBC casts are found on microscopy, when significant proteinuria is present (greater than 0.5 g per day or elevated protein-to-creatinine ratio), when creatinine is elevated or GFR is declining, or in young patients with a family history of renal disease (considering IgA nephropathy, thin basement membrane disease, or Alport syndrome). Concurrent nephrologic and urologic evaluation may be needed in some patients.

### Imaging

Renal ultrasound evaluates for hydronephrosis, renal masses, and cystic disease without radiation exposure. CT urography is the best modality for detecting upper tract urothelial carcinoma and renal masses and is reserved for high-risk patients. MR urography is an alternative when CT is contraindicated due to contrast allergy or pregnancy.

### Cystoscopy

Cystoscopy provides direct visualization of the bladder urothelium and is recommended for intermediate- and high-risk patients. It is performed by urology as an outpatient procedure with local anesthesia and can detect bladder tumors, mucosal lesions, and structural abnormalities.

![Flowchart showing the primary care approach to hematuria evaluation from initial UA through risk-based workup](images/hematuria-evaluation-flowchart.jpg)

## Special Populations

### Patients on Anticoagulation

Hematuria in patients on anticoagulants should still be evaluated because anticoagulation may unmask underlying pathology. Hematuria should not be attributed solely to anticoagulation without appropriate workup. The evaluation algorithm is the same regardless of anticoagulation status.

### Young Adults

Glomerulonephritis should be considered in young adults, with IgA nephropathy being the most common cause. Thin basement membrane disease and urinary tract infections are additional considerations. Malignancy is rare but not absent in patients under 40. The AUA guidelines recommend a less aggressive initial approach for low-risk young patients.

### Post-Menopausal Women

Post-menopausal women have a higher risk for bladder cancer, warranting a lower threshold for cystoscopy. Atrophic vaginitis should be ruled out as a confounding cause of microscopic hematuria. Urethral caruncle and vaginal bleeding contamination are additional considerations.

## Follow-Up

If the initial evaluation is negative, urinalysis should be repeated annually for at least 2 years. Persistent microscopic hematuria with a negative workup may warrant repeat cystoscopy and imaging after 1 year or if risk factors change. Nephrology referral is appropriate if proteinuria or renal function decline develops during follow-up. Gross hematuria with a negative initial workup should prompt consideration of urine cytology and close urologic follow-up.

![Surveillance protocol for patients with persistent microscopic hematuria after negative initial evaluation](images/hematuria-followup-protocol.jpg)

## Key Clinical Pearls

A single urinalysis with 3 or more RBC/HPF is sufficient to initiate evaluation; workup should not be delayed by requiring confirmatory testing. The AUA 2020 risk stratification should be used to determine the appropriate level of workup, as not every patient needs CT urography and cystoscopy. Hematuria should never be attributed to anticoagulation without completing an appropriate evaluation, because anticoagulants unmask pathology rather than cause it. Glomerular causes (dysmorphic RBCs, casts, proteinuria) warrant nephrology referral while urologic causes warrant urology referral, and some patients need both.

## References

1. Barocas DA, et al. Microhematuria: AUA/SUFU Guideline. *J Urol*. 2020;204(4):778-786.
2. Davis R, et al. Diagnosis, evaluation, and follow-up of asymptomatic microhematuria in adults: AUA guideline. *J Urol*. 2012;188(6 Suppl):2473-2481.
3. Linder BJ, et al. Urinary biomarkers and bladder cancer detection. *Nat Rev Urol*. 2015;12(11):612-624.
4. Vivante A, et al. Persistent asymptomatic isolated microscopic hematuria in Israeli adolescents and young adults and risk for end-stage renal disease. *JAMA*. 2011;306(7):729-736.