Laboratory evaluation of antigen rapid diagnostic tests to detect Ebola and Sudan viruses.

BACKGROUND

Nucleic acid-based assays are the diagnostic gold standard for filoviruses, including Ebola (EBOV) and Sudan (SUDV) viruses. However, outbreaks in areas with limited laboratory infrastructure highlight the need for simpler diagnostic tests that can be rapidly and safely used in the field.

METHODS

We evaluated eight antigen rapid diagnostic tests (Ag-RDTs) for their ability to detect EBOV and SUDV. Analytical panels using virus cell slurries were used to assess limit of detection, and clinical samples were tested to determine sensitivity and specificity.

RESULTS

Five Ag-RDTs detected EBOV and three detected SUDV, although clinical sensitivity was low (20-40 % for EBOV, 33 % for SUDV), improving only with higher viral loads. All assays demonstrated 100 % clinical specificity with no cross-reactivity.

DISCUSSION: Although none of the evaluated Ag-RDTs are suitable for routine diagnosis, some may be useful in high viral load contexts such as cadaver testing. Our findings highlight the need to improve Ag-RDT sensitivity or develop high-sensitivity point-of-care molecular diagnostics.