Pseudodiabetes mellitus manifests itself as an increase in blood glucose within a short period of time, or even positive urine glucose, with symptoms or test results similar to diabetes mellitus, but with normal pancreatic islet function, and can be seen in the following cases: 1. renal diabetes mellitus, with positive urine glucose and normal blood glucose; 2. hyperthyroidism, diffuse liver disease, after gastric and jejunal anastomosis and large amounts of carbohydrates; 3. taking diuretics, glucocorticoids, birth control pills, aspirin and other drugs; 4. some metabolic and endocrine diseases can cause secondary diabetes mellitus.