TX Q&A

When in vitro diagnostic reagents add instruments for complementary use, it is important to emphasize the similarities and differences between the intended new instruments and the approved instruments, including the instruments' registration information, structural composition, the instruments' performance, modules, as well as reaction program settings parameters and reaction systems. To visually demonstrate the similarities and differences, it is recommended to describe them using a combination of text and illustrations.

The mandatory industry standard YY 0286.1-2019 for microporous infusion filters includes the bacterial retention performance of venting holes in traditional Chinese medicine liquid filters. For selecting the evaluation method for the bacterial retention performance of venting holes, the recommendation is as follows: if the nominal pore size of the air filter membrane for venting holes is 0.22μm, YY/T 1551.2-2017 should be followed; if the air filter membrane for venting holes is not specified, YY/T 1551.1-2017 can be implemented.

Metal bone plate products usually specify hardness, bending strength and equivalent bending stiffness, corrosion resistance (if applicable), surface defects, surface roughness, appearance, compatibility performance (if the product includes both bone plates and bone screws), bone plate hole dimensions and tolerances, special series product size tolerances, and sterility performance (if applicable) in the performance indicators of product technical requirements.

The model simulating the anatomy of neurovasculature should reflect the anatomical characteristics of neurovasculature in different clinical scenarios, considering factors such as vessel diameter, curvature radius, curvature shape, number of bends, vessel length, friction coefficient of the inner vessel surface, and model material. Specifically, the model simulating the anatomy of neurovasculature should start from the proximal puncture intervention position (such as the radial artery, femoral artery) and should include at least the cervical internal carotid artery siphon segment, two 180-degree bends, and two 360-degree bends. Application materials should describe the model simulating the anatomy of neurovasculature, providing images and diagrams of the model, specifying the material of the model, and key dimensions (such as length, vessel diameter, curvature radius, etc.). It is also recommended to provide supporting data for the selection of the neurovasculature anatomy model, such as image information and relevant literature on anatomical data for the target population.

When conducting precision studies on qualitative in vitro diagnostic reagents based on immunochromatography principles such as colloidal gold method, the following factors should be considered in the experimental design: different sample concentrations, reagent batches, testing rounds, time, operators, locations, and other influencing factors. In the test results, it is essential to not only provide positive and negative results but also submit data compared to a standard color card (e.g., L1, L2, L3...) and perform consistency analysis on the color intensity.

When selecting a model to simulate the anatomy of coronary arteries for interventional devices, consider the following factors to reflect the anatomical characteristics of coronary arteries in different clinical scenarios: vessel diameter, curvature radius, curvature shape, number of bends, vessel length, friction coefficient of the inner vessel surface, and the material of the model. Reference can be made to ASTM F2394 standard for guidance. The application materials should describe the model simulating the anatomy of coronary arteries, including providing images and diagrams of the model, specifying the material of the model, and key dimensions (such as length, vessel diameter, curvature radius, etc.). It is also recommended to provide supporting data for the selection of the coronary artery vascular anatomy model, such as image information and anatomical data related literature for the target population.

Dental desensitizers fall under the category of desensitizer products in the "Medical Device Classification Catalog" (2017 Edition) as 17-10-03 desensitizer products. For physically occlusive dental desensitizer products, the desensitizing effect can be evaluated using studies on dentinal tubule sealing effects. Currently, there are two main in vitro testing methods to assess their sealing effects. The first method is dentin permeability testing, which measures the permeability values of dentin slices before and after experimental sample treatment to determine the relative permeability values of the dentin slices after treatment. The second method is scanning electron microscopy observation, where the number of open dentinal tubules in dentin slices after experimental sample treatment is observed and recorded, along with the number of open dentinal tubules in the control group. The dentinal tubule occlusion rate is calculated to evaluate the desensitizing effect. For desensitizers that require long-term use, the frequency of application should also be considered. The acceptance limits for the relative permeability values of dentin slices or the dentinal tubule occlusion rate should be explained based on their determination basis, evaluated for acceptability, and whether they can achieve the expected clinical results. For dentin desensitizing materials that react with collagen in the dentinal tubule fluid in living teeth (such as glutaraldehyde-based materials) and non-occlusive dentin desensitizing materials (such as potassium ion-based materials that reduce dentin nerve sensitivity), other methods should be considered to demonstrate the desensitizing effect of the product based on how the product functions.

Provide the confirmation basis for the disinfection program of blood dialysis equipment under the most unfavorable conditions, including the lowest concentration of the main effective ingredients, the shortest contact time, and the lowest operating temperature. At least include the log reduction value of ≥3.00 for killing Bacillus subtilis var. niger spores during simulated on-site testing. Provide research data on the impact of the disinfectant on the performance of blood dialysis equipment under clinical conditions (contact time, operating temperature, etc.), including: ① the mutual influence of the disinfectant with various components and accessories on the blood dialysis machine (such as temperature or conductivity electrodes, flow monitoring devices, etc., whether there will be an impact). ② Corrosiveness of dialysis equipment components and pipelines after long-term use. In addition, provide research basis and reasonable explanations for the number of uses.

The bonding process in the adhesive interface involves complex physical and chemical processes. The bonding effectiveness of dental adhesives can generally be evaluated and validated through various methods such as bond strength, bond durability, measurement of bonding interface gaps with dental tissue, and studies on microleakage. When conducting the above studies, it is important to consider the bonding interface of the adhesive system, taking into account the intended use of the product, actual application scenarios, and clinical application techniques. Samples should be prepared according to the instructions for the evaluation of the bonding performance and durability of the adhesive between different dental hard tissues (enamel, dentin) and different materials (metal, resin, ceramics, etc.) used as filling materials/repairs, as well as studies on microleakage and gap measurements after filling with different materials. For evaluating the bonding effectiveness, comparisons can be made under the same test conditions with similar products on the market to discuss the acceptability of the results.

If there are no changes in the composition, production process, and intended use of the in vitro diagnostic reagents, and the application is to add applicable models, and if there are no changes in the amount of reagent and sample added on the new model or if there are changes but the proportion of reagent and sample in the final reaction system remains the same, then generally there is no need to submit relevant clinical evaluation data. However, if there is a change in the proportion of reagent and sample added in the final reaction system on the new model, then corresponding clinical evaluation data should be submitted for this change during the registration modification.