Urinary ketone bodies are intermediate products of fat metabolism in the body and are produced in very small amounts under normal conditions. In normal people, urine ketone bodies are determined to be negative. A weakly positive urine ketone body indicates that there are ketone bodies inside the urine, but the amount is not large. Generally, urine tests are done in a fasting state. If the fasting state or the starvation time is longer, the body breaks down fat to provide energy, and the ketone bodies will appear positive, called starvation ketone bodies. In addition, when various causes cause repeated vomiting and diarrhea, or long-term malnutrition and long-term weight loss, ketone bodies can also be elevated and appear weakly positive for urinary ketone bodies. The most common disease state is diabetic ketosis or diabetic ketoacidosis. If the blood sugar is not well controlled, the body produces a large amount of ketone bodies, and the ketone bodies cannot be used, there will be a positive urine ketone body.