biostudies-literatureUnknown5Xie XMicroRNA (miRNA) studies are experiencing a transition from basic research applications to clinical applications. However, the lack of reliable and sensitive miRNA detection methods has become a bottleneck in the process. Here, we report an absolute quantification method based on the competitive PCR amplification of specific miRNAs and synthetic RNA spike-ins in a single reaction. RNA spike-ins are quantified as dynamic RNA copy number standards and are used to measure selected miRNAs free from the effects of intra-assay variables, including those from individual sample sources. Combined with the size differentiation power of capillary electrophoresis, the content of miRNAs was reproducibly measured, with verifiable detection limits of 10-46 copies over 5-log detection ranges. The direct measurements of miRNAs from 168 human serum samples and their considerable value as a diagnostic for bronchopneumonia and bronchiolitis demonstrate the potential of the assay in clinical applications.Scientific reports9356https://www.ebi.ac.uk/biostudies/studies/S-EPMC4366852biostudies-literatureMicroRNA-derived fragment length polymorphism assay.PMC4366852Zhang FXu KYang ZYang YFeng ZZhu JXie XZhang YTang FWu XfalseMicroRNA-derived fragment length polymorphism assay.MicroRNA (miRNA) studies are experiencing a transition from basic research applications to clinical applications. However, the lack of reliable and sensitive miRNA detection methods has become a bottleneck in the process. Here, we report an absolute quantification method based on the competitive PCR amplification of specific miRNAs and synthetic RNA spike-ins in a single reaction. RNA spike-ins are quantified as dynamic RNA copy number standards and are used to measure selected miRNAs free from the effects of intra-assay variables, including those from individual sample sources. Combined with the size differentiation power of capillary electrophoresis, the content of miRNAs was reproducibly measured, with verifiable detection limits of 10-46 copies over 5-log detection ranges. The direct measurements of miRNAs from 168 human serum samples and their considerable value as a diagnostic for bronchopneumonia and bronchiolitis demonstrate the potential of the assay in clinical applications.2015-01-01T00:00:00Z2015 Mar2026-05-03T06:51:18.581Z2026-04-07T18:57:40.543ZS-EPMC43668522579097110.1038/srep09356