From the Guidelines
Yes, a White Blood Cell (WBC) count of 26-50 in a urinalysis is considered pyuria. Pyuria is defined as the presence of an abnormal number of white blood cells in the urine, typically more than 5-10 WBCs per high-power field (HPF) 1. A count of 26-50 WBCs significantly exceeds this threshold and indicates inflammation within the urinary tract. This finding often suggests a urinary tract infection (UTI), but can also occur with other inflammatory conditions affecting the urinary system.
The presence of these white blood cells represents the body's immune response to infection or inflammation, as they migrate to the site to combat pathogens. According to the Infectious Diseases Society of America guidelines, if pyuria (≥10 WBCs/high-power field or a positive leukocyte esterase or nitrite test is present on dipstick), a urine culture (with antimicrobial susceptibility testing) should be ordered 1.
Key points to consider:
- Pyuria is a sign of inflammation in the urinary tract, which may be due to infection or other causes.
- A WBC count of 26-50 in a urinalysis exceeds the typical threshold for pyuria.
- Further evaluation, including urine culture, is warranted to identify specific pathogens and guide treatment.
- Accompanying symptoms like painful urination, frequency, urgency, or fever should be reported to a healthcare provider to guide proper management, as suggested by the guidelines for the evaluation of fever and infection in older adult residents of long-term care facilities 1.
From the Research
Definition of Pyuria
Pyuria is defined as the presence of white blood cells (WBCs) in the urine, which can be an indicator of a urinary tract infection (UTI) or other inflammatory conditions.
WBC Count in Urinalysis
The WBC count in urinalysis can vary depending on the method of analysis and the population being studied.
- A study published in 2001 2 found that a WBC count of ≥ 8 WBC/high-power field (hpf) reliably predicts a positive urine culture.
- Another study published in 2009 3 used cutoff values of > 5, > 10, > 50, and > 100 WBC/hpf to evaluate the diagnostic performance of pyuria in detecting UTIs.
- A study published in 2020 4 defined pyuria as ≥ 50 WBC/hpf and found that patients with more than one episode of pyuria had increased risks for end-stage renal disease and all-cause mortality.
Interpretation of 26-50 WBC in UA
Based on the available evidence, a WBC count of 26-50 in a urinalysis (UA) may be considered pyuria, but the interpretation depends on the specific context and population being studied.
- According to the study published in 2009 3, a WBC count of > 10 WBC/hpf had a sensitivity of 82-89% and specificity of 53-55% for detecting UTIs.
- The study published in 2020 4 used a cutoff value of ≥ 50 WBC/hpf to define pyuria, which may not be directly applicable to a WBC count of 26-50.
- However, another study published in 2001 2 suggested that a WBC count of > 2 WBC/hpf can be significant for pyuria, indicating inflammation of the urinary tract.
Key Points
- Pyuria is a common finding in patients with urinary tract infections or other inflammatory conditions.
- The interpretation of WBC count in urinalysis depends on the method of analysis and the population being studied.
- A WBC count of 26-50 in UA may be considered pyuria, but the specific context and population being studied should be taken into account.
- Further evaluation, including urine culture and clinical assessment, may be necessary to confirm the diagnosis and guide treatment. 3, 2, 4