For the second and third category of IVD reagents, at least two or three clinical trial institutions should be included in the clinical trial. The distribution of samples among the institutions should be as even as possible, including the total sample size and subgroup sample size in each institution. If the product contains multiple indications for use, subjects for the evaluation of each intended use should be distributed as evenly as possible among the institutions; if the product covers multiple markers, positive samples of each marker should be distributed as evenly as possible among the institutions. The agreement study between different sample types from homologous subjects should be completed in at least two institutions in accordance with the regulations, and the distribution of samples between institutions should also be balanced. Samples from each institution for quantitative products should cover the testing range as much as possible, and for qualitative products, each institution should include a certain number of positive and negative samples.
If there are published technical guidelines applicable, clinical trials should also implement the requirements of corresponding guidelines. For example, it is required in the Technical Guidelines for the Registration of Pathogen-specific IgM Qualitative Detection Reagents that there should be no less than 30 patients infected by the pathogen in the acute phase enrolled, their samples should be tested and the results will be compared with pathogen isolation and identification (or other methods used to determine the acute phase of infection). For another example, it is required by the Technical Guideline for the Registration of Drug Abuse Detection Reagents that a certain number (N30) of samples with the concentration in the linear range should be included and compared with the reference methods (such as gas chromatography-mass spectrometry). The test and study can be completed in one of the institutions.