What is the harm of urine routine examination occult blood eleven

In the urine routine test, the result is occult blood (+-), it is recommended to carry out red blood cell test, if no red blood cells are found in the urine, occult blood (+-), there is no harm to the body; if more than three red blood cells appear in the urine, it is considered to be a symptom caused by chronic glomerulonephritis and other diseases, and further examination is required.