PCR (polymerase chain reaction) testing is a core technology in molecular diagnostics. The standardization of its packaging and testing processes directly impacts the accuracy and biosafety of results. This article provides a professional perspective on the key quality control points throughout the PCR testing process.
Sample receipt and pretreatment are the first steps in the process. Laboratories must strictly verify sample identification, transportation conditions, and storage time to ensure sample integrity. Upon receipt, samples must be numbered and registered in a biosafety cabinet and undergo pre-processing procedures such as lysis and nucleic acid extraction based on the test type. A two-person verification system is required during this stage to prevent cross-contamination.
PCR reaction system preparation must be performed within a clean bench. Operators must wear level 3 protective equipment and use nuclease-free consumables. Reagent preparation adheres to the "unidirectional workflow" principle, moving from the reagent preparation area to the sample processing area and then to the amplification area. Negative controls, positive controls, and internal controls must be included in each reaction batch to monitor experimental validity.
During the amplification and testing phase, the PCR instrument must be pre-calibrated and temperature cycling parameters verified. The reaction procedure typically includes three steps: denaturation (94-95°C), annealing (50-65°C), and extension (72°C). The number of cycles is adjusted based on the detection target. Real-time fluorescence PCR also requires monitoring the fluorescence signal threshold of specific channels.
Result analysis and reporting must be performed by qualified technicians. Raw data must be reviewed by at least two professionals to confirm the amplification curve morphology, the plausibility of the Ct value, and the compliance of the quality control materials with the standards. The final report should include information on the test methodology, the basis for result interpretation, and a statement of test limitations.
The entire process strictly adheres to ISO 15189 and relevant CDC specifications. A triple guarantee system of environmental monitoring, equipment maintenance, and personnel training is implemented to ensure the reliability and traceability of PCR testing.