Evaluation RTFQ-PCR In The Diagnosis Of Invasive Fungal Infection

Objective: The study is designed to assess the ability of RTFQ-PCR which identify patients with high risk of IFI in clinical application and provide effective basis of clinical early diagnosis and treatment of invasive fungal infection.Methods: 1.Collecting serums and clinical data of 102 patients with high risk of IFItreated in the ICU department of Ningxia medical university general hospital from May 2015 to March 2016.2.Detect of blood culture and G test.3.RTFQ-PCR detection:(1)We get DNA of candida Albicans standard strains.Then the fungal template DNA was times diluted, determine the concentrartion,conduct RTFQ-PCR detection,and then the PCR instrument analysissoftware establishs standard curve.(2)DNA was extracted from venous serum which was drawn from patients with high invasive fungal infections risk.We next conduct RTFQ-PCR detection and collect fluorescent signals.4.Taking "Severe invasive fungal infection in patients with the diagnosis and treatment guidelines" formulated in intensive medical branch of Chinese medical association in 2007 as diagnostic criteria, we divided the patients into proven, probale,possible and non-invasive fungal infections four groups.Taking the proven and probable two groups as the positive contrast,the non-invasive infection group as the negative control,we calculate the RTFQ-PCR,and G test in sensitivity, specific, positive predictive value, negative predictive value,and then evaluate the clinical value of them.5. Blood culture as the gold standard,we calculate the RTFQ-PCR in sensitivity, specific, positive predictive value, negative predictive value.Results: 1. In 99 patients,2 cases were diagnosed as proven,20 cases as probable, 28 cases as possible and 49 cases as non-invasive infection.Taking the proven and probable two groups as the positive contrast,the non-invasive infection group as the negative control, the Sensitivity, specificity, positive predictive value, and negative predictive values of the three methods are: RTFQ-PCR:50%, 96%, 82%, 84%; G test:54%,92%,76%,88%. RTFQ-PCR combined with G test are:78%,88%,70%,91%.2. Blood culture as the gold standard, the Sensitivity, specificity, positive predictive value, and negative predictive values of RTFQ-PCR are: 100%, 88%, 15%, 100%.Conclusion: 1.RTFQ-PCR assay can be used for early diagnosis for IFI of critical patients, and has application value in the early diagnosis of IFI in clinic.2. RTFQ-PCR combined with G test, the comprehensive diagnosis is better than use alone,can improve the rate of early diagnosis of IFI.