Discussion On The Diagnostic Value Of G Test And GM Test For Invasive Pulmonary Fungal Infection

BackgroundWith the rapid development of modern medicine,the incidence of Invasive Pulmonary fungal infection(IPFI)is also increasing,and its mortality rate is high,early diagnosis is still a huge challenge for clinicians.The pancreatic fungal cell wall polysaccharide(1-3)-β-D-glucan(BG)and the Aspergillus-specific antigen galactomannan(GM)have been extensively studied and incorporated into the microorganisms diagnosed by invasive pulmonary fungal infections at home and abroad.However,studies on the diagnostic accuracy of BG and GM show different results.In addition,the clinical application of BG and GM is partially limited by false positive and false negative results.A number of studies have evaluated the diagnostic performance of BG and GM for invasive pulmonary fungal infections,but there is still no consensus on how to apply these markers in clinical practice.ObjectiveTo explore the diagnostic value of G test and GM test for IPFI.Methods(1)A retrospective analysis of 224 patients admitted to the respiratory ward of the Second Affiliated Hospital of Zhengzhou University from January 2015 to December 2018 due to pulmonary infection.Collect basic data,clinical diagnosis,and auxiliary examination results for all patients.(2)According to the "Diagnostic Criteria and Treatment Principles of IPFI" formulated by the Working Group on IPFI in China,the patients were divided into IPFI group(3 diagnostic grades,confirmed diagnosis,clinical diagnosis,suspicious diagnosis,IPFI group excluded the suspicious diagnosis)and NO-IPFI group.The IPFI group was divided into two subgroups of Aspergillus and other fungal infections based on the results of pathogenic culture.(3)The sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV)of the G test in the IPFI group and the lung subgroup of pulmonary Aspergillus infection were calculated,and evaluate the diagnostic value of the G test for IPFI.The sensitivity,specificity,PPV and NPV of the serum and BALF GM test in the subgroup of Aspergillus pulmonary infection were calculated separately,and the diagnostic value of G test and GM test for pulmonary Aspergillus infection was compared.At the same time,the diagnostic value of serum and BALF GM test for pulmonary aspergillosis infection was compared.(4)Collecting fungal culture results of all specimens from 112 patients in the IPFI group,analyze the coincidence rate of Aspergillus culture with G test,GM test and the clinical diagnostic value of Aspergillus culture for pulmonary Aspergillus infection.(5)Compare the gender,age,hospitalization time,combined chronic basic diseases and other related data of patients in the IPFI group and the NO-PFI group,and evaluate the risk factors of IPFI.Results(1)The G test is positive if the BG test value is greater than or equal to 100 pg/mL,and the sensitivity,specificity,PPV and NPV of the G test in the IPFI group were 75.00%,78.57%,77.78%,and 75.86%,respectively;the sensitivity,specificity,PPV and NPV of the G test in the subgroup of pulmonary Aspergillus infection were 77.27%,26.47%,40.48%,and 64.29%.The sensitivity,specificity,PPV and NPV of the GM test in the subgroup of Aspergillus infection of the lung were 63.64%,76.47%,63.64%,and 76.47%,respectively,when the GM test value was greater than or equal to 0.50 S/CO.The sensitivity,specificity,PPV and NPV of the BALF GM test in pulmonary Aspergillus infection were 72.73%,70.59%,61.54% and 80.00%,respectively.In the subgroup of patients with pulmonary aspergillosis infection,the sensitivity of the G test was higher than that of the GM test,and the sensitivity of the G test and the GM test was lower than the combined test;the sensitivity of the BALF GM test was higher than that of the serum GM test.(2)The area under the curve(AUC curve)of the receiver operating characteristic curve(ROC curve)of the serum G test was greater than the serum GM test(0.862>0.610);the area under the ROC curve of the BALF GM test was greater than the serum GM test(0.850>0.735).(3)The positive rate of G test in Aspergillus culture positive was 77.27%.Among the patients with positive G test,the positive rate of Aspergillus culture was 40.48%.The positive rate of GM test in Aspergillus culture positive was 63.64%;in the IPFI group with positive GM test,the positive rate of Aspergillus culture was 77.27%.(4)Gender and age were P>0.05 in the IPFI group and NO-IPFI group,which was not statistically significant.The hospitalization time was P<0.05 in the comparative analysis of the two groups,which was statistically significant,indicating that patients in the IPFI group had longer hospital stay than those in the NO-IPFI group.The chronic underlying diseases such as Chronic obstructive pulmonary disease,bronchiectasis,cerebral infarction,hypertension and coronary heart disease were P>0.05 in the two groups,which was not statistically significant.The chronic underlying diseases such as tuberculosis,diabetes,malignant tumor,autoimmune diseases,kidney diseases and chronic liver disease were P<0.05 in the two groups,which was statistically significant,indicating that it is a risk factor for IPFI.Conclusion(1)In the diagnosis of IPFI,the value of the serum G test is superior to the serum GM test.(2)For IPFI,the pathogen of infection is mainly Aspergillus,the G test has high sensitivity,and the GM test has high specificity.Combined detection of the two can reduce the rate of missed diagnosis and misdiagnosis.(3)In the diagnosis of pulmonary Aspergillus infection,the value of BALF GM test is better than serum GM test.In order to prevent missed diagnosis and over-diagnosis,the optimal threshold value can be determined according to ROC curve.(4)The IPFI group was hospitalized longer than the NO-IPFI group.Patients with chronic underlying diseases such as tuberculosis,diabetes,autoimmune diseases,kidney diseases and chronic liver disease were more likely to develop IPFI,which was a high risk factor for IPFI.