qScript™ XLT One-Step Multiplex ToughMix®, Low ROX™

qScript XLT MultiPlex 1-Step ToughMix is a ready-to-use, highly sensitive master mix for reverse transcription quantitative PCR (RT-qPCR) of RNA templates using hybridization probe detection chemistries such as TaqMan® 5’-hydrolysis probes on real-time PCR systems that do not require a passive reference dye. First-strand cDNA synthesis and PCR amplification are carried out in the same tube without opening between procedures. It is ideal for highly sensitive quantification of RNA viruses or low abundance RNA targets in uni- or multiplexed RT-qPCR applications as well as high throughput gene-expression studies. The system has been optimized to deliver maximum RT-qPCR efficiency, sensitivity, and specificity in reduced reaction volumes and fast cycle times. qScript XLT MultiPlex 1-Step ToughMix contains all required components for RT-qPCR except RNA template and probe. It is compatible with all dual-labeled probe chemistries.

qScript XLT is an engineered M-MLV reverse transcriptase (RT) with reduced RNase H activity for improved activity and stability at higher temperatures. The use of higher temperatures (50 to 54°C) for the first-strand step of one-step RT-qPCR provides higher specificity for primer annealing and disruption of RNA secondary structure that can interfere with cDNA synthesis. These beneficial properties of qScript XLT RT are further enhanced by a hot-start mechanism for the reverse transcription step. Minimizing off-target extension by the RT during reaction assembly provides highly reproducible low copy quantification as well as extended room temperature stability of fully assembled reactions for high throughput operations.

qScript XLT MultiPlex 1-Step ToughMix is highly resistant to PCR inhibitors. A key component of the ToughMix is an ultra pure, highly processive thermostable DNA polymerase that is combined with high avidity monoclonal antibodies. This provides an extremely stringent automatic hot-start that minimizes the potential for primer-dimer and other non-specific PCR artifacts.

Performance Data

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ADAR Hot-Start Plots
ADAR Hot-Start Plots

CDKN1B Hot-Start Plots
CDKN1B Hot-Start Plots

Triplex Amp Plots
Triplex Amp Plots

GAPDH IPC Duplexed 1-Step RT-qPCR
GAPDH IPC Duplexed 1-Step RT-qPCR

Real-Time PCR Instrument Compatibility

Applied Biosystems 7500
Applied Biosystems 7500 Fast
Stratagene Mx3000P®
Stratagene Mx3005P™
Stratagene Mx4000™
Applied Biosystems ViiA 7
Applied Biosystems QuantStudio™ 12K Flex
Agilent AriaMx


  • Reagent Description
  • qScript XLT One-Step RT-qPCR ToughMix (2X): 2X reaction buffer containing dATP, dCTP, dGTP, dTTP, magnesium chloride, qScript XLT reverse transcriptase, RNase inhibitor protein, hot-start DNA polymerase, and stabilizers

Storage conditions

qScript XLT Multiplex 1-Step ToughMix is stable for one year when stored in a constant temperature freezer at -20°C protected from light. Repeated freezing and thawing does not affect RT-qPCR performance.

Precautions and Disclaimer

For research use only. Not intended for any animal or human therapeutic or diagnostic use. Please consult the Material Safety Data Sheet for information regarding hazards and safe handling practices.


Cat# 95165-100 100 x 20µl rxns
Cat# 95165-500 500 x 20µl rxns