Certification of the identity and the copy number concentration of synthetic single-stranded RNA including fragments of the SARS-CoV-2 genome and part of the human RNAse P gene : EURM-014k

Certified reference material (CRM) EURM-014k has been produced in compliance with ISO 17034:2016 [1] and ISO 33405:2024 [2]. It is certified for the RNA identity and copy number. EURM-014k consists of a vacuum-dried synthetic single-stranded RNA (ssRNA) fragment deposited in a laser sealed single-use metallic mini capsule under an argon-helium atmosphere. The ssRNA includes five target regions of the SARS-CoV-2 genome and part of the human RNase P gene. The RNA identity was confirmed by sequencing. Between-unit homogeneity, as well as stability during transport and storage, were assessed in accordance with ISO 33405:2024. The material was characterised through an interlaboratory comparison involving eight expert laboratories of demonstrated competence and adhering to ISO/IEC 17025:2017 [3]. The RNA copy number was determined by methods based on reverse transcriptase droplet digital polymerase chain reaction (RT-ddPCR). The uncertainty of the certified value was estimated in accordance with ISO 17034:2016 and ISO 33405:2024, and include contributions from potential inhomogeneity, instability, characterisation, and droplet volume. EURM-014k is provided as a set of three single-use mini capsules and a shellOpener©. It is intended to be used for method calibration, quality control, and assessment of method performance. After reconstitution of the vacuum-dried RNA in 100 μL, the minimum sample size required for one measurement is 5 μL. This certification project was subjected to peer-review by both internal and external experts.