Not all injections can be inspected for insoluble particles using photoresist or microscopic counting methods. When the inspection results of the photoresist method do not meet the requirements or the test sample is not suitable for the photoresist method, the microscopic counting method should be used for measurement, and the results of the microscopic counting method should be used as the basis for judgment. The photoresist method is not suitable for formulations with high viscosity and easy crystallization, nor for injections that are prone to generating bubbles when entering the sensor. For injection solutions with high viscosity that cannot be directly measured by either method, they can be diluted with suitable solvents and measured.