Fast preparation of a long chimeric armored RNA as controls for external quality assessment for molecular detection of Zika virus.

BACKGROUND: The emergence of Zika virus demands accurate laboratory diagnostics. Nucleic acid testing is currently the definitive method for diagnosis of Zika infection. In 2016, an external quality assurance (EQA) for assessing the quality of molecular testing of Zika virus was carried out in China. METHODS: A single armored RNA encapsulating a 4942-nucleotides (nt) long specific RNA sequence of Zika virus was prepared and used as positive samples. A pre-tested EQA panel, consisting of 4 negative and 6 positive samples with different concentrations of armored RNA, was distributed to 38 laboratories that perform molecular detection of Zika virus. RESULTS: A total of 39 data sets (1 laboratory used two test kits in parallel), produced by using commercial (n=38) or laboratory developed (n=1) quantitative reverse-transcriptase PCR (qRT-PCR) kits, were received. Of these, 35 (89.7%) had correct results for all 10 samples, and 4 (10.3%) reported at least 1 error (11 in total). The testing errors were all false-negatives, highlighting the need of improvements in detecting sensitivity. CONCLUSIONS: The EQA reveals that the majority of participating laboratories are proficient in molecular testing of Zika virus.