What is the diagnostic and treatment approach for a patient presenting with symptoms suggestive of a urinary tract infection (UTI) where urinalysis is indicated?

Urinalysis in Suspected Urinary Tract Infection

Perform urinalysis with dipstick testing for leukocyte esterase and nitrite, plus microscopic examination for white blood cells, in all patients presenting with acute urinary symptoms (dysuria, frequency, urgency, hematuria, or new incontinence) to guide the decision for urine culture and antibiotic therapy. 1

When to Perform Urinalysis

Urinalysis is indicated when patients present with specific urinary symptoms:

• Acute onset of dysuria, frequency, or urgency 1
• Gross hematuria 1
• New or worsening urinary incontinence 1
• Fever combined with any urinary symptoms 1
• Suspected pyelonephritis (fever, flank pain, systemic symptoms) 2

Do NOT perform urinalysis or urine culture in asymptomatic patients, as asymptomatic bacteriuria is present in 15-50% of older adults and should not be treated except in pregnancy or before urological procedures breaching the mucosa. 1, 2

Optimal Testing Approach

The minimum laboratory evaluation should include: 1

1. Dipstick urinalysis for leukocyte esterase and nitrite 1
2. Microscopic examination for white blood cells (pyuria defined as ≥10 WBCs/high-power field) 1
3. Urine culture with susceptibility testing ONLY if pyuria is present OR dipstick shows positive leukocyte esterase or nitrite 1

A negative dipstick for both leukocyte esterase AND nitrite effectively rules out UTI with a 96% negative predictive value, making urine culture unnecessary in this scenario. 3

Specimen Collection Technique

For non-catheterized patients:

• In cooperative men: midstream clean-catch specimen or freshly applied clean condom catheter with frequent monitoring 1
• In women: in-and-out catheterization is often required for adequate specimen collection 1
• The midstream clean-catch technique with perineal cleansing does not reduce contamination rates compared to simple voided specimens in young women with acute dysuria 4

For catheterized patients:

• Change the catheter BEFORE specimen collection if long-term indwelling catheter is present and urosepsis is suspected 1
• Only evaluate catheterized patients for UTI if systemic signs are present (fever, hypotension, delirium) 3

When Urine Culture is Mandatory

Obtain urine culture (with antimicrobial susceptibility testing) in these situations: 2

• Suspected acute pyelonephritis 2
• Symptoms that do not resolve or recur within 4 weeks after treatment completion 2
• Pregnant women with any urinary symptoms 2
• Patients with recurrent UTIs 2
• Suspected urosepsis (obtain paired blood cultures as well) 1
• Atypical symptom presentations 2

Special Population Considerations

Older adults and long-term care facility residents:

• Nonspecific symptoms alone (confusion, falls, decreased intake, functional decline) do NOT warrant urinalysis or treatment 1, 3
• Urinalysis should only be performed when specific urinary symptoms are present combined with fever or systemic signs 1
• Asymptomatic bacteriuria is present in 15-50% of non-catheterized residents and essentially 100% of catheterized residents—do not test or treat 1

Uncomplicated cystitis in young women:

• Empiric treatment without urinalysis may be appropriate when classic symptoms (dysuria, frequency, urgency) are present, as dysuria alone has high accuracy for UTI diagnosis 2
• However, urinalysis helps confirm diagnosis and avoid unnecessary antibiotic use 5, 6

Timing Relative to Antibiotic Therapy

Always obtain urinalysis and urine culture BEFORE initiating antibiotics whenever possible, as antimicrobial therapy sterilizes urine rapidly within hours, leading to false-negative results and obscuring definitive diagnosis. 2

If antibiotics have already been started:

• A negative urinalysis or culture does not rule out UTI—it likely reflects antibiotic effect rather than absence of infection 2
• If symptoms persist or recur despite treatment, obtain a new urine culture to assess for treatment failure or resistant organisms 2

Common Pitfalls to Avoid

• Do not treat asymptomatic bacteriuria (except in pregnancy or before urological procedures)—this leads to unnecessary antibiotic use and increased resistance 1, 2
• Do not order urine culture without first checking urinalysis—if no pyuria or negative dipstick, culture is unnecessary and wasteful 1
• Do not rely on urinalysis obtained after antibiotics have been started to rule out UTI—the opportunity for definitive diagnosis is lost once treatment begins 2
• Do not assume pyuria alone equals infection—pyuria is commonly found in older adults with lower urinary tract symptoms like incontinence without infection present 5
• Do not perform urinalysis for telemedicine evaluations unless the patient can obtain testing at a local laboratory; if patients do not respond to initial therapy, an in-office visit with physical examination and urinalysis should be performed 1