From the Guidelines
Urinalysis should only be performed in patients with symptoms of urinary tract infection (UTI), such as fever, dysuria, gross hematuria, new or worsening urinary incontinence, and/or suspected bacteremia, as recommended by the 2024 guidelines from the European Association of Urology 1. When performing urinalysis, a clean-catch midstream urine sample collected in a sterile container is recommended. The analysis typically includes:
- Visual examination for color and clarity
- Chemical testing using dipsticks to check for specific gravity, pH, protein, glucose, ketones, blood, nitrites, and leukocyte esterase
- Microscopic examination of sediment to evaluate for red blood cells, white blood cells, epithelial cells, bacteria, casts, and crystals Proper interpretation requires consideration of both dipstick and microscopic findings together. According to the Wikiguidelines group consensus statement published in JAMA Network Open in 2024, the diagnostic value of urinalysis for UTI is limited, and the absence of pyuria can help rule out infection in most patient populations, but the positive predictive value of pyuria for diagnosing infection is low 1. Therefore, urine cultures are only necessary for complicated cases, recurrent UTIs, or suspected pyelonephritis, and not for simple uncomplicated cystitis in healthy nonpregnant patients. The minimum laboratory evaluation for suspected UTI should include urinalysis for determination of leukocyte esterase and nitrite level by use of a dipstick and a microscopic examination for WBCs, as recommended by the Infectious Diseases Society of America in 2009 1. In residents with long-term indwelling urethral catheters, evaluation is indicated if there is suspected urosepsis, and catheters should be changed prior to specimen collection and institution of antibiotic therapy 1. Overall, the use of urinalysis and urine cultures should be guided by clinical symptoms and patient-specific factors, rather than routine screening, to minimize unnecessary testing and antibiotic use.
From the Research
Urinalysis Guidelines
- Urinalysis is a crucial diagnostic tool for urinary tract infections (UTIs) 2
- Dipstick urinalysis is popular for its availability and usefulness, but results must be interpreted in context of the patient's pretest probability based on symptoms and characteristics 2
- Nitrites are likely more sensitive and specific than other dipstick components for UTI, particularly in the elderly 2
- Microscopic urinalysis is likely comparable to dipstick urinalysis as a screening test 2
- Bacteriuria is more specific and sensitive than pyuria for detecting UTI, even in older women and during pregnancy 2
Treatment Options
- First-line treatments for UTI include nitrofurantoin, fosfomycin, and trimethoprim-sulfamethoxazole (when resistance levels are <20%) 2, 3
- Nitrofurantoin is at least comparable with other UTI treatments in terms of efficacy, with clinical cure rates ranging from 51 to 94% and bacteriological cure rates ranging from 61 to 92% 4
- Patients taking nitrofurantoin reported fewer side effects than other drugs, with the most commonly reported being gastrointestinal and central nervous system symptoms 4
- Fluoroquinolones are effective for clinical outcomes but should be reserved for more invasive infections 3
- β-Lactam agents (amoxicillin-clavulanate and cefpodoxime-proxetil) are not as effective as empirical first-line therapies 3
Special Considerations
- In patients with a high probability of UTI based on symptoms, negative dipstick urinalysis does not rule out UTI 2
- Urine culture is the gold standard for detection of UTI, but asymptomatic bacteriuria is common, particularly in older women, and should not be treated with antibiotics 2
- Immediate antimicrobial therapy is recommended rather than delayed treatment or symptom management with ibuprofen alone 3
- Individualized assessment of risk factors for resistance and regimen tolerability is needed to choose the optimum empirical regimen 3