From the Guidelines
Positive leukocytes in urine, also known as pyuria, indicates the presence of white blood cells in the urine and typically suggests inflammation or infection in the urinary tract, and thus, a urine culture is necessary to document a true UTI and to guide antimicrobial management, as stated in the revised AAP guideline on UTI in febrile infants and young children 1. If you have positive leukocytes in your urine, you should consult a healthcare provider for proper evaluation, as this finding often requires treatment, especially if accompanied by symptoms like painful urination, frequency, urgency, or fever.
Possible Causes and Treatment
The most common cause is a urinary tract infection (UTI), which is typically treated with antibiotics.
- The presence of leukocytes is detected through urinalysis, but a urine culture is often needed to identify the specific bacteria causing infection and determine appropriate antibiotic therapy, as noted in the clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months 1.
- A satisfactory culture is necessary to document a true UTI, and only urine obtained by catheterization (or SPA) is suitable for culture, with a pure growth of ≥50,000 CFUs/mL of a uropathogen and urinalysis demonstrating bacteriuria or pyuria, as defined in the guideline 1.
- Antimicrobial sensitivities of isolated bacteria should be used to adjust antimicrobial choice, and follow-up in 1-2 days is important to ensure risk factors have not emerged that would increase UTI risk, as recommended in the guideline 1.
Next Steps
While waiting for medical attention, increase your fluid intake to help flush bacteria from your system.
- Leukocytes can also appear in urine due to kidney infections, sexually transmitted infections, kidney stones, or non-infectious conditions like interstitial cystitis.
- A urinalysis helps interpret the results of the urine culture, distinguishing UTI from asymptomatic bacteriuria, and a urine dipstick is slightly less sensitive, but satisfactory if microscopy is not available, as stated in the revised AAP guideline on UTI in febrile infants and young children 1.
From the Research
Positive Leukocytes in Urine
- The presence of positive leukocytes in urine is often an indicator of a urinary tract infection (UTI) 2
- A study published in 2007 used flow cytometry to analyze particles in urine and found that leukocytes in urine were between 30 and 15,000 (x10(6)/L) at presentation, with a cut-off of 20x10(6)/L 2
- The same study found that the deepest decreases in cell counts were noted during the first 24 hours after initiation of therapy and gained normal values at the end of treatment in successful outcomes 2
- Another study published in 2016 found that Escherichia coli accounted for the vast majority (93.4%) of the organisms isolated in patients with UTIs, and that resistance to trimethoprim-sulfamethoxazole was the most common antibiotic resistance 3
- A study published in 2009 found that the resistance rate for trimethoprim/sulfamethoxazole was 34% in patients with uncomplicated UTIs, and that all of the resistant microorganisms were E. coli 4
- A more recent study published in 2020 found that prior urinary infection/colonisation with trimethoprim/sulfamethoxazole-resistant Enterobacteriaceae and trimethoprim/sulfamethoxazole use within the past 12 months were predictors of trimethoprim/sulfamethoxazole resistance among urinary isolates 5
Urinary Tract Infections and Antibiotic Resistance
- UTIs are among the most common bacterial infections in the adult population, and are prevalent in all age groups both in women and men 3
- The treatment of UTIs has been complicated by the emergence of resistance to most commonly used antibiotics 4
- A study published in 2007 found that flow cytometry can be used to analyze particles in urine and provide early information about the outcomes of therapy 2
- Another study published in 2016 found that fosfomycin could be a viable option for the treatment of uncomplicated UTIs, especially in patients who are resistant to trimethoprim-sulfamethoxazole 3