EpiScript™ Reverse Transcriptase PLUS (EpiScript RT PLUS) is a recombinant MMLV reverse transcriptase with greatly reduced RNase H activity combined with a blocking agent that significantly reduces activity at ambient temperatures (Figure 1). This reduced RT activity reduces non-specific amplification during RT-qPCR reaction setup and storage. When paired with a hot start Taq DNA Polymerase, such as RapiDxFire hot start Taq DNA Polymerase, a fully assembled RT-qPCR reaction mix can be stored at room temperature before use resulting in a stable relative fluorescence PCR signal (Figure 2).  This is especially important for automated, high throughput RT-qPCR workflows where low amounts of viral RNA may escape detection (false negatives). 

EpiScript RT PLUS is fully activated at standard cDNA synthesis reaction temperatures > 42 °C and remains active up to 55°C to achieve higher target specificity. Like EpiScript RNAse H- Reverse Transcriptase, EpiScipt RT PLUS is efficient at producing both short and full-length cDNA from long RNA templates. 

EpiScript RT PLUS, manufactured in an ISO 13485-certified facility, is available at a concentration of 100 u/µL in small development sizes to large scale production batches to assist you through the diagnostic test development process. Custom formulations are available upon request. 

EpiScript RT PLUS is intended for use as a general purpose reagent in molecular diagnostic assays that are based on RT-PCR target detection technologies by clinical laboratory professionals located in the United States. This product must be qualified and validated by clinical laboratory end users for suitability in the detection of any specific target using the procedures in this Manual as guidance. This product is classified as a general purpose in vitro diagnostic device reagent in the United States as defined in: 21CFR 864.4010.  Figure 1. EpiScript RT PLUS contains an additive that significantly reduces reverse transcriptase activity at room temperature. The comparison between EpiScript RNAse H- Reverse Transcriptase (EpiScript RT) and EpiScript RT PLUS was conducted by measuring the amount of incorporation of dTTP into acid-insoluble material in 2 hours at 25°C using saturating amounts of oligo(dT)-primed poly(rA) as template. 

Figure 2. EpiScript RT PLUS enhances RT-qPCR reaction specificity and robustness compared to EpiScript RT. The comparison was conducted using RapiDxFire qPCR Master Mix in fully assembled RT-qPCR reactions that were incubated for 2 hours at ambient temperatures prior to PCR cycling. Each reaction utilized the 2019-nCoV ValuPanel Assay (N1N2E) and extracted Accuplex™ SARS-CoV-2 Verfication Panel at 12 copies per reaction.  Real-Time detection of PCR products was performed using a BioRad CFX C1000 Touch™ thermocycler.  Note - results may vary depending on the sample preparation and assay design.