External quality assessment of enterovirus detection and typing

Reported are the results of a study of an enterovirus proficiency panel for use in isolation and serotyping and/or the polymerase chain reaction (PCR) carried out by 12 laboratories in nine European countries. Eleven laborato ries reported results of virus isolation and serotyping. In addition, four laboratories reported results of a PCR for enterovirus detection. Correct v irus isolation results were obtained for 105 of 110 samples (95.5%, four fa lse-negatives, one false positive), and correct PCR results for 39 of 40 (9 7.5%, one false-negative), The highest isolation rate (87.5%) was observed in primary and tertiary monkey kidney cells, on monkey kidney cell lines, h uman diploid fibroblasts or human heteroploid cells the isolation rare vari ed between 64% and 71.4%. Serotyping results were less satisfactory. Only 6 3 of 106 (59.4%) isolated viruses were typed correctly. Major problems were seen with samples containing mixtures of enteroviruses and with enteroviru s 71 or echovirus 4, with 9%, 50%, and 55% correct results, respectively. T hese results underline the need for improvement of enterovirus typing, espe cially in view of the poliomyelitis eradication initiative.