Habitual diarrhea commonly involves patients with crampy abdominal pain, abdominal distention, and altered bowel habits. It is important to recognize that there are differences in bowel function between normal individuals. Normal stools can range from even three times a day or twice a week, but should be formed without hardness, bloodless, and expelled without cramping pain or distress. Common tests: 1. Coxsackievirus antibodies Coxsackievirus antibodies are important in determining coxsackievirus infection. coxsackievirus antibodies can be detected in the sera of patients with type 1 diabetes. Positive coxsackievirus antibodies can also be seen in aseptic encephalitis, pediatric pneumonia, pediatric diarrhea, myasthenia gravis, viral myocarditis and early abortion in pregnant women caused by coxsackievirus infection. 2. Urinary citrulline Checking citrulline and its metabolism in urine can be used as a screening test for hereditary amino acid abnormalities. Increased concentration of citrulline in the blood can spill over into the urine, and the amino acid urine mainly associated with hereditary diseases includes citrulline urine. 3.Total gastric acidity measurement Total gastric acidity measurement can understand the secretion of gastric acid, which is useful for the diagnosis of stomach-related diseases. Increased gastric acid is seen in ulcer disease, hyperacidic gastritis, pyloric obstruction, and gastrinoma (secretion of gastric acid is often 3-6 times more than normal). 4.Serum electrolytes Serum electrolytes are mainly detected by electrolyte analyzer for reliable results of electrolyte content for reference in the diagnosis of clinical diseases.