Application of Procalcitonin Test in Lower Respiratory Tract Infection

OBJECTIVE To evaluate the diagnosis value of the procalcitonin(PCT) test in the lower respiratory tract infection(LRTI),and to provide the application of PCT in the bacterial infectious disease.METHODS Procalcitonin concentrations were measured using the quantitative immunofluorescence test in 93 patients and the results were compared with the levels of C-reactive protein(CRP) and white blood cell count(WBC).Samples were collected and divided into 2 groups,one including 63 cases(bacterial infected group) the other including 30 cases(non-bacterial infected group) corresponding to their clinical diagnosis(temperature,heart rate,bacteremia culture,CRP,WBC count).RESULTS The levels of PCT in bacterial infected group were significantly higher than in non-bacterial infected group(P0.001).The threshold of PCT concentration was 0.12ng/ml,and the sensitivity were 96.82% and specificity 96.66%.The threshold of CRP was 20 mg/L,with sensitivity 89.79% and specificity 47.05%.The threshold of WBC was 10.55×109/L with sensitivity of 60.32% and specificity of 63.33%.PCT was significantly better and specific for bacterial infection,diagnosis than CRP or WBC count.CONCLUSIONS Procalcitonin test is an a important marker for early diagnosis of infection in LRTI.In patients with bacterial infection the PCT is an important index for assessment of severity of disease and prognosis.The PCT test can improve the accuracy of clinical diagnosis.