Degree of pyuria alone doesn't predict UTI

The study's findings back the recommendations of the current guideline against antibiotic treatment based only on urine analysis. Also, it informs the future design of randomized controlled trials investigating interventional strategies for pyuria patients with nonspecific complaints.

Pyuria is a urinary condition linked to white blood cells. This condition can be identified through a urine test. Pyuria diagnosis is made in cases having at least ten white blood cells in each cubic millimeter of urine, often indicating infection. However, persistent white cell counts in sterile pyuria appear during testing sans bacteria infection.

Pyuria is a useful import marker for the UTI diagnosis. Pyuria interpretation may be particularly critical in patients with nonspecific complaints. There is a lack of data showing the usefulness of pyuria alone for bacteriuria or urinary tract infection diagnosis. Considering this, Bo Cheng, LewisGale Hospital Montgomery, Blacksburg, Va, and colleagues aimed to define the relationship between pyuria and positive bacterial growth in urine culture; also determined the diagnostic utility of cutoff points of different urine white blood cells.

Stratification of urine microscopy results was done by white blood cell count and correlated with the positivity of urine culture bacterial growth. For this purpose, the researchers selected 46,127 patients older than 18 from the HCA Healthcare System Capital Division inpatient population. Based on the receiver operating characteristic curve plot, the optimal urine white blood cell cutoff was derived.

The study led to the following findings:

• Urine microscopy finding of white blood cell 0-5 cell/hpf, 5-10 cell/hpf, 10-25 cell/hpf, and higher than 25 cell/hpf was respectively associated with 25.4%, 28.2%, 33%, and 53.8% rates of bacteriuria.
• The receiver operating characteristic curve plot showed that pyuria alone did not provide adequate diagnostic accuracy to predict bacteriuria.
• The optimal cutoff point for the best sensitivity and specificity combination was 25 cells/hpf.

"Pyuria alone does not provide adequate diagnostic accuracy for bacteriuria prediction. Urinary count of white blood cells greater than 25 cell/hpf was the optimal cutoff for bacteriuria detection," the researchers wrote in their study.

"The findings of our study support the current recommendation against antibiotic treatment based solely on urine analysis. It also informs the future design of randomized controlled trials that examines interventional strategies for patients with pyuria and nonspecific complaints," they conclude.

Reference:

Cheng B, Zaman M, Cox W. Correlation of Pyuria and Bacteriuria in Acute Care. Am J Med. 2022 Sep;135(9):e353-e358. doi: 10.1016/j.amjmed.2022.04.022. Epub 2022 May 14. PMID: 35580716.