Evaluation of the pneumococcal urinary antigen test (PUT): a retrospective study.

Objectives: To determine the usefulness of the pneumococcal urinary antigen test (PUT) and to describe the characteristics of pneumococcal pneumonia.

Methods: In this retrospective study, we examined the effects of prior antibiotic treatment, pneumonia onset period, and sputum quality on the results of PUT. Clinical information was collected via medical records from all adult patients who were hospitalized at the Fujita Health University Bantane Hospital with "pneumonia" as a new diagnosis from April 2015 to March 2018.

Results: A total of 482 patients with pneumonia were included, of whom 103 had pneumococcal pneumonia. The frequency of PUT positivity did not differ significantly in patients with a pneumonia onset period of ≥3 days compared with those with a period of ≤2 days (=0.514). Patients with a history of prior antimicrobial therapy had a significantly lower rate of positive sputum culture vs those with no such history (=0.005); however, PUT positivity in the two groups did not differ significantly (=0.367).

Conclusions: Our results showed that urinary antigen testing for pneumococcal pneumonia is useful for diagnosis regardless of prior antibiotic treatment and time since symptom onset.