Utility of terminal hemadsorption for detection of hemadsorbing respiratory viruses from conventional shell vial cultures for laboratories using R-Mix cultures

Abstract Background Many laboratories using R-Mix cell lines inoculate other shell vial cultures to improve the recovery of viruses, and in particular, perform terminal hemadsorption (THad) following 10–14 days of incubation to improve detection of respiratory viruses. We explored the cost-effectiveness and added benefits of THad on conventional shell vial cultures from respiratory samples for laboratories using R-Mix cell lines. Objectives To determine if eliminating the practice of THad from conventional shell vial culture when R-Mix cultures are negative, would result in a significant reduction in the number of hemadsorbing respiratory viruses detected. Study design THad results were retrospectively reviewed for 41,129 respiratory shell vial cultures that were set up concurrently with R-Mix cultures. Results Greater than 95% of hemadsorbing respiratory viruses were recovered by R-Mix standard protocol within 24 h of inoculation, and only 5% were detected by THad at 10–14 days. Conclusion The practice of hemadsorption at days 10–14 for conventional shell vial cultures from respiratory specimens should be discontinued for laboratories using R-Mix due to its low yield, questionable clinical impact of delayed results and additional costs.