Utility of procalcitonin as a diagnostic biomarker for bacterial infections and its comparison with C reactive protein and total leucocyte count

Abstract

Background: Distinguishing bacterial fever from other fevers is important for early treatment and the judicious use of antibiotics. This study aimed to evaluate the levels of procalcitonin (PCT) in febrile adults and compare it with C reactive protein (CRP) and total leukocyte count (TLC). Methods: 70 patients were classified clinically according to severity of infection into mild (Group A 30), moderate (Group B 23) and severe (Group C 17). 30 healthy controls were taken (Group D). After a detailed clinical history, their blood collected aseptically was sent for complete hemogram, culture, biochemistry, PCT and CRP. PCT was measured by immunochromatographic method (Result Range: 2, >10ng/ml). CRP was measured by immunoturbidometry. Chisquare, ANOVA, Pearson’s Correlation were used. Results: PCT was significantly elevated with higher degrees of infection (p value < 0.001). Sensitivity and specificity of PCT in Group 2 and 3 were both 100%. Group 1 had no rise in PCT proving that it is neither specific nor sensitive for mild infection. Mean CRP was significantly increased (p value <0.001) with severity of infection; sensitivity and specificity being 97.14% and 80%. TLC increased significantly (p value <0.001) with the severity of infection. However, it did not rise above the cut off, for mild infection. Conclusions: PCT was highly sensitive and specific for moderate to severe infection and also determined prognosis. It could not identify mild local infection. CRP was sensitive for any grade of infection but not specific for bacterial fever. TLC was specific for moderate to severe infection though less sensitive.