Evaluation of the Tetracore Orthopox BioThreat® antigen detection assay using laboratory grown orthopoxviruses and rash illness clinical specimens

► The Tetracore Orthopox BioThreat® Lateral Flow Assay was evaluated. ► The assay detected reproducibly laboratory grown vaccinia and monkeypox viruses containing 107 pfu/ml. ► In a blind study, 9 of 11 orthopoxvirus clinical samples were identified accurately. ► In a blind study, only 1 of 11 non-orthopoxvirus clinical samples (including varicella, pseudocowpox, Orf and HSV-1) produced a false positive result.