In a 20‑year‑old male with a small amount of blood in urine, normal dip‑stick urinalysis and negative nucleic‑acid amplification tests for gonorrhea and chlamydia, what is the most appropriate next step in management?

Management of Small Blood in Urine in a 20-Year-Old Male with Negative Urinalysis and Negative STI Testing

In a 20-year-old male with visible blood in urine but a negative dipstick urinalysis and negative gonorrhea/chlamydia testing, the most appropriate next step is to obtain a microscopic urinalysis to confirm or exclude true hematuria, because dipstick tests can produce false positives from myoglobin, hemoglobin, or other substances, and true hematuria requires ≥3 red blood cells per high-power field on microscopic examination. 1

Initial Diagnostic Clarification

Verify True Hematuria with Microscopy

• The dipstick finding must be verified with microscopic urinalysis showing ≥3 RBCs/HPF on at least one properly collected clean-catch midstream specimen before initiating any workup, as dipstick tests have limited specificity (65-99%) and can produce false positives. 1

• If the patient reports visible blood but the dipstick is negative, this discrepancy suggests either:

  • Factitious causes such as food substances (beets, blackberries) or medications coloring the urine without actual red blood cells 2
  • Contamination from sources other than the urinary tract 1
  • Intermittent hematuria that was not present at the time of testing 3

Examine for Associated Urinary Findings

• Check the microscopic urinalysis for proteinuria, dysmorphic RBCs, red cell casts, pyuria (≥10 WBCs/HPF), and nitrites to determine whether the source is glomerular versus urologic. 1

• The presence of pyuria and hematuria together suggests urinary tract infection, which requires urine culture and antibiotic treatment. 1

Age-Appropriate Risk Stratification

Low Malignancy Risk in This Age Group

• In a 20-year-old male, urinary tract malignancy is exceedingly rare, and extensive urologic evaluation (cystoscopy, CT urography) is not indicated for isolated asymptomatic microhematuria. 1

• The most common factors associated with urinary malignancy include age >35 years, male gender, smoking, occupational chemical exposure, and gross hematuria; this patient's age places him at very low risk. 2

Consider STI-Related Urethritis Despite Negative Testing

• In men <35 years, sexually transmitted pathogens (C. trachomatis or N. gonorrhoeae) are the most common causes of urethritis, even when initial testing is negative. 4

• If the patient has dysuria, urethral discharge, or urethral discomfort, confirm urethritis with objective criteria: mucopurulent discharge on exam, Gram stain showing ≥5 leukocytes per oil-immersion field, positive leukocyte esterase on first-void urine, or ≥10 leukocytes per high-power field on microscopic examination of first-void urine. 4

• Nucleic acid amplification tests (NAATs) are more sensitive than culture for C. trachomatis and should be the preferred diagnostic method. 4

Management Algorithm Based on Microscopy Results

If Microscopy Confirms True Hematuria (≥3 RBCs/HPF)

With Pyuria or Signs of Infection

• Obtain urine culture before starting antibiotics if hematuria is accompanied by dysuria, frequency, urgency, or fever. 1

• Treat confirmed UTI with oral antibiotics for 7-14 days, but do not attribute hematuria solely to UTI without follow-up urinalysis after treatment completion, as persistent hematuria requires further evaluation. 1

Isolated Microscopic Hematuria Without Proteinuria

• Children and young adults with isolated microscopic hematuria without proteinuria or dysmorphic RBCs should not undergo extensive imaging initially; instead, repeat urinalysis in 1-2 weeks to determine if hematuria persists. 1

• If hematuria persists on repeat testing, obtain renal ultrasound, serum creatinine and BUN, and blood pressure measurement to assess renal function and structure. 1

• If initial workup is normal but hematuria persists, repeat urinalysis at 6,12,24, and 36 months with blood pressure monitoring at each visit. 1

Gross (Visible) Hematuria

• Gross hematuria always requires urgent evaluation with renal ultrasound and nephrology or urology referral, even if self-limited, as it carries a higher risk of significant pathology and has a 30-40% association with malignancy in older adults. 2, 1

• However, given this patient's age (20 years), the probability of malignancy remains very low despite visible blood, but evaluation is still warranted to exclude other significant pathology. 2

If Microscopy Shows No RBCs (False-Positive Dipstick)

• No further urologic workup is indicated if microscopy confirms the absence of red blood cells. 1

• Counsel the patient about factitious causes of red-colored urine (foods, medications) and reassure that no pathologic hematuria is present. 2

Critical Pitfalls to Avoid

• Do not perform extensive urologic evaluation (cystoscopy, CT urography) in young adults with isolated asymptomatic microhematuria, as malignancy is exceedingly rare in this age group and these invasive tests are not indicated. 1

• Do not ignore the combination of hematuria and proteinuria, as this requires nephrology referral regardless of symptom severity. 1

• Do not attribute persistent hematuria to recent UTI without confirming resolution with repeat urinalysis after antibiotic completion. 1

• Do not defer microscopic urinalysis in favor of dipstick alone; the dipstick has insufficient specificity to guide clinical decisions without microscopic confirmation. 1

Special Considerations for STI Evaluation

If Urethritis Symptoms Are Present

• Even with negative gonorrhea and chlamydia testing, consider empiric treatment if the patient has confirmed urethritis and is unlikely to return for follow-up, using ceftriaxone 250 mg IM single dose plus doxycycline 100 mg orally twice daily for 7 days. 5, 4

• All sexual partners within the preceding 60 days must be evaluated and treated to interrupt transmission chains. 5, 4

• Advise the patient to abstain from sexual activity for at least 7 days after therapy initiation and until symptoms have resolved. 5

If No Urethritis Symptoms

• Routine screening for HIV and syphilis should be offered as part of comprehensive STI evaluation in sexually active young adults. 5