Comparison of samples of blister fluid and scales in the diagnosis of dermatomycosis

Background The successful diagnosis of dermatomycosis depends on specimen collection. Dermatomycosis is sampled mainly for scales, but there is a lack of research on specimens of blister fluid. Objectives To explore whether blister fluid can diagnose dermatomycosis and compare blister fluid and scale specimens for dermatomycosis diagnosis. Methods From April to July 2021, we prospectively gathered 34 patients who needed to meet all inclusion criteria simultaneously and collected their blister fluid and scales as specimens. The two samples were tested by fluorescent stain microscopy, fungal culture and PCR, and the diagnosis results were compared. Results The blister fluid sample's sensitivity, specificity and accuracy were 90%, 100% and 94.1%, respectively, whereas the scales sample were 60%, 100% and 76.5%, respectively. The positive likelihood ratios were >10 for both blister fluid and scales specimen, and the negative likelihood ratios were not