Discussion about Procalcitonin in the Diagnosis of Blood Stream Infection

摘要

Objective Compare different cut-off points of procalcitonin (PCT) in diagnosis of blood stream infection with patients in centre ICU. Methods Data about patients with blood stream infection diagnosed with PCT and blood culture in first afflicated hospital of Chongqing medical university from June 2011 to February 2014 were respectively analyzed. Blood was cultured in Bact/Alert 3D, a fully automatic consecutive detection system. Pathogens were indentified using VETEK 2, a fully automatic microorganism identifier. PCT was detected with VIDAS, a fully automatic immunal analyzer. Results When cut-off point of PCT in diagnosis of blood stream infection with patients in centre ICU is 1.075, the positive rate of PCT was 57.3%. The sensitivity and specificity of PCT were 93.3% and 50.6% respectively with a positive and negative predictive value of 26.1% and 97.6%.When cut-off point of PCT in diagnosis of blood stream infection with patients in centre ICU is 0.5, the positive rate of PCT was 69.6%. The sensitivity and specificity of PCT were 97.8% and 35.7%respectivelywith a positive and negative predictive value of 22.1% and 98.8%.When cut-off point of PCT in diagnosis of blood stream infection with patients in centre ICU is 0.05, the positive rate of PCT was 93.0%. The sensitivity and specificity of PCT were 97.7% and 7.8% respectivelywith a positive and negative predictive value of 15.8% and 95%.Conclusion The detection of PCT has a certain sensitivity and specificity in diagnosis of blood stream infection, but we shouldn’t diagnose all patients with the same one cut-off point of PCT. This test shows that for patients in centre ICU, when diagnosed with cut-off point resulted with analysis of PCT values of patients in the same department, the efficiency was higher than diagnosed with cut-off point resulted with analysis of PCT values of patients in various departments. So, the first cut-off point is better in diagnosis of blood stream infection of patients in centre ICU.