Real-Time Quantitative PCR System

What is the Real-Time Quantitative PCR System?

A 96-well instrument that measures fluorescence during each cycle to quantify target nucleic acid without opening the tube. It supports gene expression studies, pathogen load measurement and diagnostic assay validation with standard curves.

Overview

The real-time quantitative PCR system combines a thermal block of 96 wells with an optical module that excites fluorescent dyes and reads emission once per cycle. Common chemistries are intercalating dyes such as SYBR Green I and sequence-specific hydrolysis probes, and instruments offer two to six optical channels with matched LED and filter combinations. Software converts fluorescence into amplification curves, determines the cycle threshold with a baseline and threshold setting, and calculates concentration from a standard curve with efficiency between about 90 and 110 percent. Melting curve analysis follows most dye-based assays to confirm a single product. Data handling includes reference gene normalisation, replicate averaging, melt temperature reports and MIQE-oriented export fields. Temperature uniformity and precise optics determine how well replicates agree.

How does it work?

PCR copies a target sequence with a thermostable DNA polymerase such as Taq, two primers that flank the target, deoxynucleoside triphosphates and a buffer. A thermal block cycles the reaction from about 95 °C, where double-stranded DNA separates, to 50 to 65 °C for primer annealing, then 72 °C for extension. Repeating 25 to 45 cycles doubles the product each round, so amplification is exponential while reagents last. Endpoint cyclers read the product afterwards on a gel or capillary system, while real-time instruments measure fluorescence each cycle using an intercalating dye or a hydrolysis probe, and the cycle threshold reflects the starting template amount. Quantitative results need a standard curve or reference gene, and melting curve analysis checks product specificity or detects sequence variants by high-resolution melting. Reverse transcription adds a step for RNA targets.

What are the key features?

• 96-well block with two to six optical channels.
• LED excitation with matched emission filters.
• Support for intercalating dyes and hydrolysis probes.
• Cycle threshold and standard curve analysis software.
• Melting curve module for dye-based specificity checks.
• Reference gene normalisation and MIQE-oriented export.

What are the technical specifications?

A typical real-time quantitative pcr system configuration offers block format of 96 x 0.2 mL, 384-well option, optical channels of 2-6, LED with filter sets, excitation range of 450-680 nm, emission range of 500-730 nm, temperature range of 4-99 °C and temperature uniformity of ±0.3 °C at 72 °C. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Real-Time Quantitative PCR System is used in gene expression and transcript quantification, pathogen load measurement, microRNA and copy number assays and assay validation and efficiency checks. Across the wider PCR class, laboratories also deploy it for gene expression analysis and transcript quantification, pathogen detection in clinical and food samples and genotyping and mutation screening.

Which standards and certifications apply?

Relevant standards and methods include ISO 13485 manufacturing, MIQE guidelines, CLSI MM03-A2, CLSI MM06-A2, IEC 61010-1 and IVDR (EU) 2017/746. Certification candidates for this model are CE, ISO 13485 manufacturing and IVDR (EU) 2017/746; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Keep pre-amplification and post-amplification work in separate areas with dedicated pipettes and filter tips, because carryover of amplicon is the main cause of false positives. Clean surfaces and equipment with fresh hypochlorite or a validated decontaminant, use UV where available and change gloves often. Calibrate block temperature and optical channels annually with a reference thermometer and dye plate, and check uniformity across the block. Verify performance with positive and negative controls and a standard curve in every run, and record Ct, efficiency and melt temperatures. Store primers and probes in small aliquots at the recommended temperature to avoid repeated freeze-thaw cycles, and protect fluorescent probes from light.

How do I select the right Real-Time Quantitative PCR System?

Select this system for quantification, pathogen load measurement or assay validation, where fluorescence per cycle is essential. Compare the number of optical channels with your multiplexing needs and check channel-to-channel crosstalk. Confirm block uniformity, sensitivity in copies per reaction, ramp rate and the analysis features you need. Include the software licence and any qualification package in the quotation.

How does it compare with other PCR variants?

Decide first whether you need qualitative detection, relative or absolute quantification, or sequence variant discrimination, because that separates endpoint cyclers from real-time and melt systems. Next, set the number of optical channels, since multiplex panels need two to six channels and matching filter sets. Throughput follows the plate format: 96 wells suits most laboratories, while 384-well plates and automation fit high-volume screening. Check block type, maximum ramp rate, temperature uniformity and gradient capability, which help with new primer sets. For field work, consider size, power options and tolerance of ambient temperature. Confirm analysis software, export formats, primer and probe support, and the validation documentation your quality system requires.