Crescendo cDNA synthesis has been designed from the ground up to provide dramatically improved sensitivity over the standard single strand cDNA synthesis method. Utilizing Tecan’s user-friendly SPIA® (Single Primer Isothermal Amplification) technology, Crescendo cDNA synthesis generates more copies of each RNA transcript than standard first strand cDNA synthesis methods making it ideal for the detection of low abundance transcripts.
Crescendo amplified cDNA provides better detection of SARS-CoV-2. A 10-fold dilution series of SARS-CoV-2 RNA, ranging from 250 to 250,000 copies was added to a background of 2.5 ng of K562 total RNA. The RNA was converted to cDNA using a standard first strand synthesis kit or the Crescendo cDNA Synthesis for qPCR kit. The CDC SARS-CoV-2_N2 TaqMan assay showed that SARS-CoV-2 was detected significantly earlier with the Crescendo amplified cDNA compared to the first strand synthesis method which required significantly more PCR cycles at the low input ranges increasing the potential for false negative results.
In testing with nasal swabs from COVID-19 patients, Crescendo cDNA synthesis outperformed standard first strand Synthesis techniques across all samples (see below). Compared to standard first strand synthesis, CDC developed TaqMan SARS-CoV-2 probes demonstrated superior detection ability with Crescendo amplified cDNA even with high human RNA background.
With high-quality samples the Crescendo cDNA synthesis protocol consistently returned a result at a much earlier cycle point. On average across all samples tested, the Crescendo-amplified samples were detected by TaqMan 10.8 cycles earlier than samples amplified using standard first strand techniques. Crescendo provided higher quality experimental data with less background than first stand cDNA synthesis.
For low-quality samples (see above), with very low target copy number, Crescendo was still able to return a positive result, while the first strand amplification failed to detect the presence of SARS-CoV-2 at all. In this instance, a researcher using first strand amplification would have recorded a false negative result and missed the presence of the virus.
By converting your starting sample to cDNA, Crescendo cDNA Synthesis for qPCR kit brings several advantages:
At the heart of the Crescendo cDNA Synthesis for qPCR kit is Tecan’s proprietary Single Primer Isothermal Amplification (SPIA) technology, a well-established, highly published, and peer-reviewed method for generating cDNA libraries from RNA samples. SPIA is an unbiased amplification technique which preserves biological information from your samples. A rapid, user friendly protocol that is compatible with challenging sample sources enabling better amplification of your transcript of interest.
For Research Use Only. Not for use in diagnostic procedures.