False-negative result of serum cryptococcal antigen lateral flow assay in an HIV-infected patient with culture-proven cryptococcaemia.
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ABSTRACT:
SUBMITTER: Borges MASB
PROVIDER: S-EPMC6849355 | biostudies-literature | 2019 Dec
REPOSITORIES: biostudies-literature
Publications
False-negative result of serum cryptococcal antigen lateral flow assay in an HIV-infected patient with culture-proven cryptococcaemia.
Borges Moara Alves Santa Bárbara MASB Araújo Filho João Alves de JA Soares Renata de Bastos Ascenço RBA Vidal José Ernesto JE Turchi Marília Dalva MD
Medical mycology case reports 20191101
The detection of cryptococcal capsular antigen (CrAg) is very sensitive and specific, however false-negative results have been reported, mostly in cerebrospinal fluid. We report the case of an HIV-infected patient with CD4 = 42 cells/mL, asthenic, negative serum CrAg lateral flow assay (LFA) and culture-proven cryptococcaemia. Despite the high accuracy of LFA, false-negative result is possible. Careful clinical evaluation and close follow-up are relevant. ...[more]
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| S-EPMC4503809 | biostudies-literature
Project description:ObjectivesCryptococcosis remains a severe global health concern, underscoring the urgent need for rapid and reliable diagnostic solutions. Point-of-care tests (POCTs), such as the cryptococcal antigen semi-quantitative (CrAgSQ) lateral flow assay (LFA), offer promise in addressing this challenge. However, their subjective interpretation poses a limitation. Our objectives encompass the development and validation of a digital platform based on Artificial Intelligence (AI), assessing its semi-quantitative LFA interpretation performance, and exploring its potential to quantify CrAg concentrations directly from LFA images.MethodsWe tested 53 cryptococcal antigen (CrAg) concentrations spanning from 0 to 5000 ng/ml. A total of 318 CrAgSQ LFAs were inoculated and systematically photographed twice, employing two distinct smartphones, resulting in a dataset of 1272 images. We developed an AI algorithm designed for the automated interpretation of CrAgSQ LFAs. Concurrently, we explored the relationship between quantified test line intensities and CrAg concentrations.ResultsOur algorithm surpasses visual reading in sensitivity, and shows fewer discrepancies (p < 0.0001). The system exhibited capability of predicting CrAg concentrations exclusively based on a photograph of the LFA (Pearson correlation coefficient of 0.85).ConclusionsThis technology's adaptability for various LFAs suggests broader applications. AI-driven interpretations have transformative potential, revolutionizing cryptococcosis diagnosis, offering standardized, reliable, and efficient POCT results.
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| S-EPMC3864499 | biostudies-literature
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Project description:BACKGROUND:Cryptococcal antigen (CrAg) screening at the point of care could improve cryptococcal meningitis prevention where laboratory resources are limited. We evaluated the accuracy of Immunomycologics (IMMY, Norman, OK) CrAg lateral flow assay (LFA) using different techniques at point of care. SETTING:Two tertiary-level hospitals in Johannesburg and a community health clinic in Soweto, South Africa. METHODS:A case-control diagnostic validation study and a prospective clinic-based implementation study using the IMMY CrAg LFA on finger-prick blood. Accuracy, using direct application of LFA to sample, or pipette to transfer sample to diluent, and reading after 10 and 20 minutes, was compared with laboratory-based plasma testing. RESULTS:The validation study tested 64 CrAg-positive and 152 CrAg-negative patients with no symptoms or signs of meningitis, identified by routine laboratory screening, recruited by convenience sampling. Consecutively diagnosed HIV-infected adults (n = 654) were included in the implementation study. Sensitivity was 82% and 20% when the LFA was read 10 minutes after direct application to finger-prick blood in the validation and implementation studies, respectively. Using a pipette to transfer blood and reading after 20 minutes improved sensitivity to 100%, while retaining 100% specificity, in both studies. CONCLUSIONS:Although the IMMY CrAg LFA performs well when applied directly to finger-prick blood for diagnosing cryptococcal meningitis, this technique may not provide adequate volume to detect low concentrations of CrAg when screening asymptomatic patients. Using a pipette to transfer larger volumes of blood to diluent before CrAg LFA testing and reading results after 20 minutes is a more reliable point-of-care method.
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