Abstract
Purpose :
Beta-D-glucan (BDG) is a component of most fungal cells walls and can be assessed with an FDA approved enzymatic-based colorimetric assay. This assay can provide results faster than fungal blood cultures. We sought to evaluate the ophthalmic utility of beta-D-glucan (BDG) testing in patients with concern for fungal infection.
Methods :
A retrospective case control study was carried out in patients who underwent BDG testing for concern of fungemia. 356 unique patients were identified between April 2013 to May 2018 at the University of Pennsylvania. Medical charts were reviewed for BDG test values, blood culture results, eye examination findings on presence in either eye of chorioretinitis or vitritis/fungal endophthalmitis. The sensitivity and specificity and their 95% confidence intervals (95% CI) using three cutpoints of BDG test values (≥80 as positive; ≥ 250 and ≥500 as high positive values) were calculated using positive fungal blood cultures with chorioretinitis or endophthalmitis as the gold standard for defining cases.
Results :
The study had 9 cases of chorioretinitis and 2 cases of fungal endophthalmitis confirmed by positive blood culture. Defining BDG values ≥80 as test positive, BDG testing had a sensitivity of 78% (95% CI: 45-94%) for chorioretinitis and 100% (95% CI: 34-100%) for fungal endophthalmitis with a specificity of 71% (95% CI: 66-75%). When defining BDG values ≥250 as test positive, the sensitivity was 56% (95% CI: 27-81%) for chorioretinitis and 100% (95% CI: 34-100%) for fungal endophthalmitis with a specificity of 85% (80-87%). When defining BDG values ≥500 as test positive, BDG testing had a sensitivity of 56% (95% CI: 27-81%) for chorioretinitis and 100% (95% CI: 34-100%) for fungal endophthalmitis with a specificity of 87% (95% CI: 83-90%). Similar results were found when analyses were performed only among those with an eye examination.
Conclusions :
A negative BDG test decreases the likelihood of fungal chorioretinitis or endophthalmitis/vitritis. The majority of patients with chorioretinitis in the setting of a positive fungal culture had a positive BDG. Both patients with a positive culture and endophthalmitis/vitritis had a positive BDG test, suggesting utility in endophthalmitis cases. BDG testing may be a useful adjunct in the evaluation of patients with concern for fungal chorioretinitis and/or endophthalmitis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.