Validity of procalcitonin for the diagnosis of bacterial infection in elderly patients.

INTRODUCTION: PCT has been consolidated as a key tool in the diagnosis of bacterial infections in general population. Few studies have been conducted to determine the applicability of this test in elderly patients. METHODS: Study of validity of PCT on elderly patients. Two groups were formed; the first group was formed by patients aged 75 years or older, under bacterial infection criteria and PCT on the initial Lab test. The second group was formed by patients aged 75 years or older with any noninfectious disease; these patients were asked PCT in the initial Lab test. Sensitivity, specificity, positive and negative likelihood ratio were calculated. RESULTS: 161 patients were included, 95 with probable bacterial infection and 66 without infection. Patients with probable bacterial infection criteria, 72% of them had PCT >0.5 ng/mL. Patients without infection, 8% of the patients had PCT >0.5 ng/mL. Sensitivity and specificity of PCT to bacterial infection with the cutoff value of 0.5 ng/mL was 72% and 92%, respectively. CONCLUSION: PCT can be used in elderly patients to diagnose bacterial infections because it has proved good sensitivity and high specificity.