One plus and one minus sign of occult blood indicates the presence of a small amount of red blood cells in the urine, which is a phenomenon of mild kidney damage. There are many clinical diseases that can cause positive urine occult blood, the most common of which is glomerulonephritis, but a simple positive occult blood does not have any effect on kidney disease and will not cause aggravation, so there is no big problem, regular review is fine. If there are no other accompanying symptoms, you can use medication, pay attention to diet and regular review. The indicators that need attention are urine protein, occult blood and kidney function. When the urine protein is positive, it indicates kidney damage and needs to be treated with drugs to protect the kidneys and reduce urine protein. Although occult blood alone has no effect on kidney disease, urine protein is damaging to the kidneys and can cause kidney failure in severe cases. It is best not to eat animal meat, liver and foods and drugs containing more iron within three days before the occult blood test, and it is best for women to avoid menstruation and to have multiple tests in a row if necessary to ensure the accuracy of the test.