Clinical Evaluation Of The Isothermal Amplification Assays For The Detection Of Four Common Respiratory Viruses In Children With Pneumonia

Background:Respiratory viruses are recognized as serious causes of morbidity and mortality in lower respiratory tract infection patients.Isothermal amplification assays are increasingly used in the virus detection for the advantages of rapidity,simplicity and cost-effectiveness compared to traditional molecular diagnostic methods.However,systematic assessment of these assays in the clinical settings is rarely reported.Methods:MEDLINE(Pubmed)search was done through subject headings and words in the abstract related to isothermal amplification assay and virus.The selected loop-mediated isothermal amplification assays(LAMP)for respiratory syncytial virus(RSV),human metapneumovirus(HMPV),adenovirus(ADV)and a reverse transcription genome exponential amplification reaction assay(GEAR)for human rhinovirus(HRV)were clinically evaluated by a head to head comparison with a two-tube multiplex reverse transcription-PCR(RT-PCR)assay(two-tube assay)using 634 respiratory specimens of children with pneumonia from different regions in China.The discrepant results between isothermal amplification-assays and two-tube assay were resolved by sequencing.The comparison of sensitivities of each selected isothermal amplification assay among province,gender,and age groups was analyzed.Results:A total of 634 respiratory specimens selected from Hebei Province children's hospital and Hunan Provincial Center for Disease Control and Prevention were tested.The overall detection rate(number of positive specimens/total specimens)for viruses tested by Reverse transcription(RT)-LAMP/LAMP/RT-GEAR was 35.9%while the detection rate was 46.2%by the two-tube assay.The sensitivity of each isothermal amplification assay was 88.4%,74.3%,100%and 73.6%for RSV,HMPV,ADV and HRV,respectively.No false positives were found in isothermal amplification assays.All the discrepant negative results by isothermal amplification assays were confirmed false negatives by sequencing.The LAMP assay for ADV showed the complete consistence with the two-tube assay.A higher sensitivity of RSV detection was found in Hunan Province than that in Hebei Province(P=0.01).Among age groups,a higher sensitivity of RSV detection was also found in children older than 1 year than those less than 1 year(P=0.01).Conclusions:The clinical performance of each selected isothermal amplification assay for different viruses varies.Multiple-center assessment is critical to evaluate isothermal amplification assay,especially of RNA virus,for the broad use in clinical hospital.The selected LAMP assay for the detection of ADV is reliable and has great potential use in clinics while the sensitivities of LAMP/GEAR assays for the detection of RSV,HMPV and HRV need to be further improved.