Assessment of the Alinity m HSV1&2/VZV assay for quantitative analysis across multiple off-label sample types

The Alinity m HSV1&2/VZV assay (Abbott Molecular) enables the detection of human herpesviruses HSV-1, HSV-2, and VZV in lesion swab specimens transported in viral transport media. Its performance in alternative specimens has not been validated. This study evaluates the assay's reliability in detecting and quantifying these viruses in alternative specimen types. The assay was evaluated against the ELITe BeGenius system using commercially available reference panels diluted in amniotic fluid (AF), bronchoalveolar lavage (BAL), cerebrospinal fluid (CSF), plasma, and two different transport media (VTM from Liofilchem and InActiv Blue®). We also compared results between both techniques for clinical lesion swabs in transport media. The Alinity m assay detected all expected targets in reference materials but exhibited higher detection limits (LoD) compared to the ELITe system. Estimated LoDs ranged in Log₁₀C/mL from 1.7 to 2 for HSV-1, from 1.7 to 2.7 for HSV-2, and from 2.7 to 3.7 for VZV, depending on the matrix. However, considering amplification signals above Abbott's threshold off, the LoD for HSV-1 and HSV-2 can be reduced to 1.7 Log₁₀C/mL for CSF and transport media, while the LoD for VZV can be reduced to 1.7 Log₁₀C/mL in CSF and AF and to 1 Log₁₀C/mL in InActiv Blue®. Among clinical samples (n = 43), five discrepancies were observed, primarily in cases with low viral loads. While the Alinity m assay is effective for lesion swabs, it has limitations in alternative matrices. It may be useful for plasma testing, but ELITe remains more sensitive for detecting low viral loads.