Discussion on Registration Regulations and Quality Control Key Points of Monkeypox Virus Nucleic Acid Detection Kit (Fluorescence PCR Method)

Registration Classification and Submission Pathway

According to the classification defined by the National Medical Products Administration (NMPA), the Monkeypox Virus Nucleic Acid Detection Kit (Fluorescent PCR Method) is generally regulated as a Class III medical device among in vitro diagnostic reagents and must obtain medical device registration approval before it can be marketed and sold. The applicant should submit product technical requirements, analytical performance evaluation data, clinical evaluation data (which may be based on clinical trials or comparison with equivalent products), stability study data, etc. Note: After the 2022 monkeypox outbreak, the NMPA launched an emergency approval procedure. Relevant companies may pay attention to the special approval channel for innovative medical devices or the emergency approval channel to accelerate the product launch process. However, regardless of the channel used, the evidence for product safety and effectiveness must be complete and authentic.

Key Points of Analytical Performance Evaluation Indicators

In registration submissions, the performance evaluation of the Monkeypox Virus Nucleic Acid Detection Kit (Fluorescent PCR Method) needs to cover the following key indicators:

Limit of Detection (Analytical Sensitivity): The concentration level of the detection limit must be clearly defined, and validation data must be provided;

Analytical Specificity: Cross-reactivity validation must be conducted against the major genotypes of monkeypox virus and common closely related viruses (such as vaccinia virus, cowpox virus, and other clades of monkeypox virus); simultaneously, the effects of endogenous interfering substances (such as hemoglobin and triglycerides) and exogenous interferents (such as antiviral drugs) should be investigated;

Precision: Including repeatability, intermediate precision, and reproducibility; evaluation is usually required under different operators, different instruments, and different laboratory conditions;

Linear Range: Evaluate the linear relationship of the reagent within the expected detection range using serial dilution samples.

The specific acceptance criteria for the above indicators may refer to recommended industry standards such as YY/T 1727 "Nucleic Acid Extraction Kit" and YY/T 1826 "Fluorescent PCR Detection Kit."

Establishment of Reference Materials and Quality Control Materials

To ensure the reliability of test results, the Monkeypox Virus Nucleic Acid Detection Kit (Fluorescent PCR Method) should be equipped with appropriate reference materials:

Positive Reference Material: Usually a plasmid containing the target nucleic acid sequence of monkeypox virus or an inactivated virus strain, used to verify the effectiveness of the reagent;

Negative Reference Material: Normal human genomic DNA or common viral nucleic acids (such as Epstein-Barr virus, cytomegalovirus, etc.) may be used to assess specificity;

Internal Control (Internal Reference): Monitor nucleic acid extraction efficiency and PCR inhibitory factors throughout the entire process;

Cut-off Reference Material: Used to evaluate the interpretation stability near the limit of detection.

Manufacturers should specify in the instructions the purpose, usage method, and expected result interpretation criteria for each reference material.

Stability Studies and Transport Validation

The stability of the kit includes long-term stability (shelf life under simulated real storage conditions), accelerated stability (accelerated by high temperature or light exposure), and open-vial/freeze-thaw stability. In addition, since monkeypox virus nucleic acid detection typically involves cross-regional distribution, transport simulation tests (such as vibration and temperature changes) are required to ensure that the kit performance is not affected during cold-chain transportation.

Compliance Differences Between Commercial Kits and Laboratory Developed Tests (LDTs)

Monkeypox Virus Nucleic Acid Detection Kits (Fluorescent PCR Method) that have obtained NMPA registration can be directly used for clinical diagnosis. For LDT methods developed by some laboratories according to their own needs, if registration approval has not been obtained, they are limited to scientific research or public health emergency scenarios and must not be directly used for clinical reporting. During public health emergencies, they may be evaluated and used in accordance with relevant temporary management provisions, but subsequent gradual standardization is still required. Companies should pay attention to regulatory developments to ensure continuous compliance throughout the product lifecycle.