Diagnostic Accuracy of Cryptococcal Antigen Lateral Flow Assay Compared With Microscopy and Culture in Suspected...

Introduction Cryptococcosis is a serious fungal infection that can occur in both immunocompromised and immunocompetent individuals and may be fatal when diagnosis is delayed. Rapid and reliable point-of-care testing can facilitate early diagnosis and timely initiation of treatment. Therefore, this study aimed to assess the diagnostic performance of the lateral flow assay (LFA) for cryptococcal meningitis, using microscopy and fungal culture as reference methods. Materials and methods This comparative observational study was conducted at Mahatma Gandhi Memorial Medical College in Indore, India, over a period of six months (April-September 2025). The cerebrospinal fluid (CSF) samples (n=60) from patients with suspected meningitis were considered for the study. All CSF samples were examined using India ink preparation, and culture was done on Sabouraud dextrose agar, whereas LFA was done on both CSF and serum samples using Biosynex CryptoPS (Biosynex SA, Illkirch-Graffenstaden, France). The results of microscopy and culture were then compared with LFA. Results Among 60 suspected meningitis patients, eight grew Cryptococcus in culture which was regarded as the gold standard for confirming the diagnosis of cryptococcal meningitis. Direct microscopy had a specificity of 100%. However, its sensitivity was less, i.e., 62.5%. LFA was also performed on both CSF and serum of the same patients, further yielding good sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV), thus confirming its reliability as a rapid diagnostic tool. Conclusion LFA emerges as a game-changer in the rapid diagnosis of cryptococcal meningitis. It offers excellent concordance with culture while offering superior speed and bedside utility over traditional methods. As a true point-of-care innovation, LFA bridges the gap between clinical suspicion and early treatment initiation, a step that can be life-saving in resource-limited settings.