Answer： (Reply to the first question): Currently, there are no technical guidelines specifically for central laboratories in China, and most of them refer to the relevant documents of the US CAP. The central laboratory has a wide range of testing projects, and the corresponding acceptance standards for each project are also different. Therefore, specific testing analysis should be combined. The quality control indicates that the relative error of the new instrument is within an acceptable range, but there is a system error of 5-10% compared to the original system, which is an absolute deviation. If this situation occurs within the same project, it is necessary to try to avoid the impact of systematic errors on efficacy statistical indicators. If all backup samples are still within the stable period, retesting can be conducted to reduce system bias, but it should be noted that: 1. The initial analysis of raw data and reports should be treated equally with project files, and reported in the report; 2. All retesting operations and results reporting methods should be defined in writing in advance to avoid subjective operational biases and value selection reporting situations in the later stage; 3. Due to sample retesting; There may be situations where the deviation between the retest value and the initial measurement value is greater than the system error, which is 10%. Special attention should be paid, as future verification may be questioned. (Reply to the second question): The GCP regulations themselves do not have detailed regulations on laboratory technical requirements. Relevant laboratory retests are based on technical guidelines in the relevant field. Taking the PkPD sample bioanalysis laboratory as an example, the industry currently follows the relevant technical guidelines of the United States and EMA for retesting, develops the laboratory's own SOP, and clearly specifies any retesting situation in the specific project's biological sample analysis plan. Although there is no clear provision in GCP, laboratory sample retesting remains the focus of clinical project verification. The laboratory not only needs to determine the operation and judgment of retesting from a technical perspective, but also needs to avoid the risk of subjective judgment and data tampering from a normative perspective.