Technical Note: Negative Interference of Ashwagandha, an Indian Ayurveda Medicine Indicated for Preventing COVID-19, in IL-6 Immunoassay.

ABSTRACT

OBJECTIVE: Ashwagandha, an Indian Ayurvedic medicine is indicated to prevent COVID-19 infection. Because IL-6 and C-reactive protein are widely measured to determine risk of cytokine storm in hospitalized COVID-19 patients, we studied potential interference of ashwagandha on these two assays. Previous studies indicated that ashwagandha may interfere with digoxin assay, so we also studied potential interference with digoxin assay. MATERIALS AND METHODS: We obtained one ashwagandha product from India (liquid extract) and one product from US (Herb Pharma; liquid extract). We prepared two serum pool each for IL-6, C-reactive protein and digoxin by combining appropriate left-over specimens submitted to our hospital laboratory for such tests. Then aliquots of each pools were supplemented with 10, 25 or 50 µL of ashwagandha extract followed by re-analysis for appropriate analyte and comparing values with original pool. RESULTS: We observed negative interference of ashwagandha with IL-6 assay only (Indian product showed more negative interference) but C-reactive protein assay and digoxin assay were not affected. Negative interference of ashwagandha in IL-6 assay has not been reported before. CONCLUSION: We conclude ashwagandha caused negative interference in IL-6 assay.