Assessment of an Antigen Lateral Flow Assay (LFA) For Point of Care Diagnosis of Cryptococcosis in Senegal

Abstract

Background: Cryptococcal meningitis is a medical emergency. Therefore, simple, rapid and efficient diagnostic techniques are needed. New rapid diagnostic tests based on the detection of cryptococcal antigen have been developed. The aim of our study was to evaluate the performance of the Dynamiker Cryptococcal Antigen Lateral Flow Assay (LFA) in our routine diagnosis activities. Materials and Methods: We performed a prospective study from November 2017 to August 2018 at the ParasitologyMycology laboratory of the CHNU of Fann in Dakar. Biological samples collected from HIV-infected patients hospitalized at the infectious diseases department of CHUN de Fann were used. Serum, CSF and urine samples received in the laboratory were examined using mycological techniques and the cryptococcal latex agglutination test (CLAT). The performance of the Dynamiker test was evaluated considering CLAT as the reference method. Results: A total of 39 samples were examined: 14 CSF, 24 sera and 1 urine sample. The average age was 44.5 years with a predominance of female patients (64.1%). The mean CD4 count was 73 cells/mm3 . Among the 39 samples tested, 23.1% were CLAT positive while 30.8% were LFA positive. The sensitivity and specificity rates were 100% and 75% respectively. The percentage of correlation between the two methods was 92.3%. The intensity of the bands on the LFA was high en 66.7% of cases. Conclusion: The excellent sensitivity of the rapid Cryptococcal Antigen Lateral Flow Assay and the rapidity of obtaining results (less than 15 minutes) make it suitable for routine diagnosis of cryptococcal meningitis.