[Usefulness of semi-quantitative procalcitonin test in respiratory medical practice].

PURPOSE: A lot of investigators have reported about the diagnostic and prognostic value of procalcitonin (PCT) for severe bacterial infection. We evaluated the usefulness of semi-quantitative PCT test in respiratory medical practice. METHODS: A retrospective study was performed from June to December 2008 at the Chugoku Rosai General Hospital, Hiroshima, Japan. This study analyzed consecutive adult patients, including outpatients and inpatients, who developed systemic inflammatory response syndrome (SIRS) and their PCT were measured semi-quantitatively within the first 24 hours of onset or first visit. We extracted 87 patients with respiratory disease and analyzed their clinical data. RESULTS: Study patients were divided into two groups: 61 patients with bacterial infection and 26 patients without it. Semi-quantitative PCT test (cut-off value; > or = 0.5 ng/ml) showed sensitivity of 55.7% and specificity of 84.6% for diagnosis of bacterial infection. The diagnostic value of PCT was higher than that of CRP and WBC but it was thought to be not enough to accurate diagnosis. The patients with high PCT value (> or = 2.0 ng/ml) showed higher death rate than the patients without it (36.4% vs 7.7%, P = 0.016). CONCLUSION: Semi-quantitative PCT test, which anyone can use quickly and easily, has great prognostic value and limited diagnostic value for respiratory bacterial infection.