In order to ensure the stability of the kits between different batches, each new batch will be repeatedly tested and fine-tuned. The new and old customers and customers should pay more attention to it. The electronic version of the manual is for reference only. The manual in paper along with kit shall prevail. In particular, everyone should pay more attention to the adjustment of the weight of the standard. Before doing the experiment, it is necessary to dilute the standard with an accurate volume of the standard dilution to avoid the deviation of the OD value of the test result.