Diagnostic performance of two lateral flow assays for measurement of mannan antigen and anti-mannan IgG antibodies in patients with candidemia: a retrospective case-control study

Introduction: Candidemia is the forth most common blood stream infection on intensive care units and is associated with a high mortality. Rapid diagnosis is essential for timely initiation of antifungal therapy. We aimed to analyse the performance of two lateral flow assays (LFA) for the measurement of mannan antigen and anti-mannan antibodies in sera of patients with candidemia.

Methods: Serum samples of 250 patients with blood culture-proven candidemia and 200 controls were tested with the TECO^® Fast Candida mannan antigen LFA and the TECO^® Fast Candida IgG antibody LFA, respectively. Both assays have a turn-around-time of approximately 40 min. The control sera were taken from hospitalized patients with negative blood cultures (n=140) and bacteremia (n=60), respectively.

Results: The mean age of the study patients was 64.6 years and 63.5% were male. Candidemia was caused by Candida (C.) albicans (46.6%), C. glabrata (27.7%), C. parapsilosis complex (9.9%), C. tropicalis (5.1%), C. krusei (4.7%), C. lusitaniae (1.6%) and other Candida spp (1.2%). A mixed candidemia occurred in 3.2% of patients. The sensitivity, specificity and area under the ROC-curve (AUC) was 46.2% (95%-CI: 40.0-52.6), 87.1% (95%-CI: 81.6-91.4) and 0.667 (95%-CI: 0.621-0.710) for TECO mannan antigen; 45.1% (95%-CI: 38.9-51.4), 75.6% (95%-CI: 69.1-81.4) and 0.604 (95%-CI:0.557-0.649) for TECO anti-mannan-antibodies and 65.9% (95%-CI: 59.7-71.7), 65.7% (95%-CI: 59.7-71.7) and 0.658 (95%-CI:0.612-0.701) for the combination of both assays.

Conclusion: The diagnostic performance of the TECO^® Fast Candida Ag & IgG LFAs is comparable to the widely used Platelia Candida Ag and Ab Plus enzyme immunoassays (EIA). However, the LFA format is much more practical, especially for small sample numbers, and the time-to-result compared to the EIA is significantly reduced.