The invention relates to the field of nucleic acid amplification, particularly to quality control materials for use in viral RNA assays. It specifically relates to the construction of a recombinant Pestivirus by the identification of a region in the 3′NTR of the viral RNA genome where additional sequence elements can be stably inserted. Chimeric Pestivirus with sequence insertions in the 3′ nontranslated region (3′NTR) of the viral RNA genome were stable in replication and capable of forming infectious, RNase resistant virus particles. This chimeric Pestivirus with a 3′NTR insertion can be utilized as a quality control material in analytical assays for RNA targets, including external, internal controls, quantitative standards in PCR and NAT nucleic acid assays.