Comparison of the results between quantitative procalcitonin detection and blood culture

Objective To evaluate the application value of the quantitative procalcitonin (PCT) test in bloodstream infection. Methods Of 1066 patients with blood culture and PCT detection were collected in our hospital, retrospectively, 1010 were effective cases.The relationship between blood culture results and serum PCT levels was investigated.PCT levels in gram-negative bacterial infection, gram-positive bacterial infection and candidiasis were compared. The prognosis of 33 blood culture positive patients with repeated PCT detection results were analyzed. Mann-Whitney U test was used to compare the PCT value among the three groups, and Fisher′s test was used to compare the death rate among the three groups. Results In the patients with negative blood culture results, the median of PCT was 0.37(0.11-1.67) μg/L. But in the patients with positive blood culture results, the median of PCT were 2.24(0.57-11.59) μg/L. The positive rate of PCT in gram-negative bacteria infection, gram-positive bacterial infection and candidiasis were 86.6%, 72.0% and 75.7%, respectively. In the 33 patients subjected to repeated PCT detections, the mortality of the patients with decreasing PCT was lower than the others. The patients whose PCT levels were greater than 5 μg/L had poor prognosis. Conclusions Quantitative PCT is proved to be an effective method for rapid diagnosis of bloodstream infection. The changing trends of PCT test results has certain reference value for the patients′ prognosis.（Chin J Lab Med,2012,35:243-246） Key words: Bacteremia; Fungemia; Calcitonin; Protein precursors; Bacteria; Candida; Microbiological techniques