These are the test results—what could be the cause?

From the report, the dog’s eosinophil count is zero and immunity is low—it essentially has little defense against disease, though this could also be a problem with the blood sample or testing machine. In addition, the dog’s C-reactive protein is high, indicating clear inflammation in the body, but the exact cause can’t be determined directly.

Finally, the high blood sugar may be hyperglycemia from an organ metabolism problem, but it could also be from eating high-glycemic food or receiving IV fluids before the test. So the dog’s lack of appetite may be affected by internal inflammation or abnormal organ metabolism; the specifics need other symptoms and more detailed results to judge.