A study of serum procalcitonin in acute febrile illness as a predictor of bacterial infection and its comparision with leucocytosis

Abstract

Background: Infectious diseases still remain a challenge despite great advances in medicine. It is often difficult, but necessary to differentiate between viral and bacterial infections to guide appropriate antibiotic usage. Serum Procalcitonin is a marker of bacterial infection and its level can be quickly available within a few hours making it a useful guide for prompt initiation of antibiotics in an acute febrile illness while awaiting bacterial culture and sensitivity results, which requires as long as 72 hours to be available.Objectives: To study the levels of serum procalcitonin in acute febrile illness and its correlation with bacterial culture and sensitivity. To compare the sensitivity, specifity and accuracy of serum procalcitonin to that of total leucocyte count in predicting bacterial infections.Materials and methods: A total of 68 adults presenting with an acute febrile illness were included in the study. Serum procalcitonin, total leucocyte count were measured and samples sent for bacterial culture and sensitivity immediately on admission, before the institution of therapy. The correlation of serum procalcitonin with bacterial culture and sensitivity was studied and its sensitivity, specificity and accuracy in predicting bacterial infection were evaluated.P value was calculated using Chi-square test.Results: A highly significant association was found between elevated serum procalcitonin levels of >0.5 mg/ml and a positive culture for bacteria (P <0.0001). The association between elevated total leucocyte count and a positive culture was not statistically significant (P value=0.231). The sensitivity and specificity of serum procalcitonin as a diagnostic marker of bacterial infection was 61% and 92%respectively with an accuracy of 94%. The sensitivity of elevated total leucocyte count in detecting bacterial infection was 55% and the specificity was 65% with an accuracy of 58%.Conclusion: Serum procalcitonin is a useful marker of bacterial infection and is more reliable than total leucocyte count in predicting bacterial infection.