| Objective:Using enzyme-linked immune fluorescence analysis technology of quantitative detection of serum PCT and fully automatic blood culture instrument for blood culture, the quantitative detection of serum PCT in the diagnosis of bloodstream infections in the sensitivity, specificity, positive predictive value and negative predictive value, blood culture positive rate and false positive rate in diagnosis of blood stream infection, analysis of different concentration of calcitonin original level distribution of the pathogen and blood culture positive rate; Calcitonin original quantitative detection and blood cultures of these two kinds of detection methods in diagnosis of advantages and disadvantages of bloodstream infections, relevance, and the clinical application value.Methods:1. Select samples Shanxi medical university first hospital between December 2012 and October 2014 clinical patients with bloodstream infections, highly suspected during simultaneous blood culture and PCT test of 900 cases of patients, according to the inclusion criteria to select the appropriate specimens.2. PCT detection Calcitonin original using Enzyme-Linked Fluorescent Assay(ELFA) technology, the detection principle is to step in with final fluorescence immunoassay clamp method to test for quantitative detection, provided by the French merry Emmanuel company mini VIDAS auxiliary reagent and instrument testing and calibration, and quality control in accordance with requirements.3. Blood culture Using automatic blood culture instrument, first of all, high fever, chills, clinical symptoms in patients with sterile blood, HP requires enough, aseptic conditions into the aerobic and anaerobic bottles, and inspection in time. Put blood culture bottle timely at 37 ℃ BACT/ALERT3 D automatic blood culture systems, prompt, positive and negative signal by computer BACT/ALERT3 D blood culture instrument automatic alarm for positive culture bottle, general steps of discharging bottle, strains in time through using sterile syringes to blood culture medium, medium chocolate and macconkey medium at the same time, the smear gram staining, and inform the results of smear microscopy to clinical, as a clinical doctor the basis of a preliminary diagnosis of disease. Will be the first two kinds of culture medium on 5% CO2 incubator, macconkey medium in the ordinary incubator under the condition of 35 ℃ for 24 h after observations. To produce pure strains using automatic microbe susceptibility system identification. To achieve set a time(5 d)report negative bottle for regular step unloading bottle, sterile growth report blood culture.Results:1. Samples of blood culture positive for inspection at the same time in our data in 170 patients, blood culture positive rate was 20.7%. Among them, 65 cases of bacteria for pollution decontamination bacteria, positive rate was only 12.8%, false positive rate was7.9%, 650 cases blood culture negative.2. PCT truncation point 0.5 ng/m L, the sensitivity of PCT in the diagnosis of bloodstream infections is 71.67%, specificity of 93.57%, positive predictive value was65.65%, negative predictive value of 95.07%.3. PCT in different detection range of positive blood cultures also produces change,both are positively related, as the concentration of PCT increased positive rate of blood culture is increasing, and PCT > 50 ng/m L, blood culture positive rate reached 83%.Conclusions:The commonly used method of blood cultures are often used as a diagnostic bloodstream infections, can clear bloodstream infection of pathogenic bacteria and their drug susceptibility spectrum, so as to guide clinical rational use of antibiotics, but it also has many disadvantages, the highest rate of blood culture separation in this study was epidermis staphylococcus, were isolated from 69 cases, 65 cases were judged for pollution,contamination rate of 7.9%, and blood culture positive rate was only 12.8%, analyzed the reason of blood culture positive rate is low, may be due to in the process of actual operation, not sure the optimal timing of blood, as 3 armour hospital, many patients to our hospital before already use of antibacterial drugs, making bacteria growth is restrained,leading to blood culture negative. The activity of PCT is a hormone-free glycoprotein, was the former substance p, calcitonin is produced by the thyroid C cells[5]. In this study, with the increase of concentration of PCT, the positive rate of blood culture is raised, the PCT >50 ng/m L, blood culture positive rate reached 83%. Due to the PCT test time is short, so with the help of early detection of PCT result can predict positive rate of blood culture, and combined with the clinical experience administration, has very important significance for disease control. In this study, there are 45 cases in the bloodstream infections PCT > 0.5ng/m L, alone in the diagnosis of blood stream infection depends on PCT has certain drawbacks, so we need to combination of blood culture and some other indicators and clinical comprehensive evaluation. Serum PCT as index of early detection of bacterial infection, high sensitivity and specificity, but not clear is what caused by bacteria infection,and blood culture can ultimately identify pathogenic strains and their drug susceptibility spectrum, make up for the deficiency of the PCT test, both joint detection, can not only improve the diagnosis of blood stream infection, and promote the clinical rational use of antibiotics, and the diagnosis and treatment of patients with bloodstream infections has a certain guiding significance. |
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