Significance of G Test [(1-3)-β-D-Glucan Assay] in the Diagnosis and Guidance of Clinical Medication of Invasive Fungal Infection

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Objective: G test [(1-3) -β-D-glucan assay] was a novel texting method for invasive fungal infection (IFI). The study evaluated the diagnostic value of G test for IFI by comparing G test with fungal culture method，and analyze the guiding significance of G test and fungal culture in clinical medication. Methods: 373 inpatients with suspected IFI in the first affiliated hospital of Jinan university from January to December 2017 were retrospectively analyzed. G test and fungal culture results were collected, and their positive rate, sensitivity, specificity, positive and negative predictive values were calculated. The value and rationality of G test for clinical diagnosis of IFI was evaluated by taking the relief and cure of infection symptoms of patients as clinical effective criteria. Results: Among 373 suspected IFI patients, the positive rate of G experiment was 39.95%, higher than that of fungus culture (28.95%, P<0.001). The positive rate of combined G test and fungal culture was 43.70%. To evaluate the consistency of G test with fungal culture method, κ value was 0.596 (P<0.001). When positive fungal culture was used as the criterion for the diagnosis of IFI, the sensitivity, specificity, positive predictive value and negative predictive value of G test for the diagnosis of IFI were 87.04%, 79.25%, 63.09% and 93.75%, respectively. All 373 patients with IFI received antifungal therapy, and the effective rate of the both methods positive group was 72.34%, higher than 42.86% in the only fungal culture positive group (P=0.033) and 30.48% in the both methods negative group (P<0.001). The effective rate of the only G test positive group was 58.18%, higher than that of the both methods negative group (30.48%, P<0.001). There was no significant difference in the therapeutic efficiency between the only G test positive group and the only fungal culture positive group (P=0.303). Conclusion: G test was an effective diagnostic method of IFI, and combined with fungal culture could improve its positive rate and have a higher guiding value for clinical medication.