To explore the role of procalcitonin (PCT) in the diagnosis of severe pulmonary infection in order to provide suggestions for rational drug uses.

A total of 90 hospitalized patients with severe pulmonary infection from our hospital were taken as the experimental group, and 30 healthy volunteers from the outpatient health examination were used as the control group. In the present study, the experimental group was divided into three subgroups according to the disease category: pulmonary infection combined with positive blood culture subgroup (positive group, n=30), simple bacterial pulmonary infection subgroup (bacterial group, n=30), and viral pulmonary infection subgroup (viral group, n=30). And the results of PCT, CRP and WBC of all the patients were collected and analyzed on the admitted day, 3 days of treatment, and 7 days of treatment, respectively. Statistical analyses were performed with SPSS software (Version 16.0, SPSS Inc, Chicago, IL).

Significant difference was found in the results of PCT, CRP and WBC between the positive group and the bacterial group and the control group (P<0.01). There was no significant difference in the results of PCT between the viral group and the control group (P>0.05), however, significant difference was found in the results of CRP and WBC between the two groups (P<0.01). Significant difference was found in the results of PCT and WBC between the positive group and the bacterial group (P<0.01), while no significant difference was found in the results of CRP between the two groups (P>0.05). The PCT values decreased gradually with the improvement of pulmonary infection, with statistical significant difference between the groups.

PCT is a sensitive indicator of the early diagnosis of bacterial infectious diseases in the lungs. It has great significance in judging the patient′s condition, evaluating the therapeutic effects of antibiotics and de-escalation therapy, and assessing the prognosis of the patient.