The common STDs that can cause occult blood in urine are gonococcal urethritis, mycoplasma urethritis, chlamydia urethritis, etc. However, occult blood in urine is not necessarily caused by STDs, and whether or not it is an STD is not dependent on whether or not there is occult blood in urine. The causes of urinary occult blood are mainly inflammation, stones and tumors and other diseases. In addition, women’s physiological period, some systemic diseases, etc. will also have the occurrence of urinary occult blood. 1. Inflammation: such as acute and chronic glomerulonephritis, pyelonephritis, cystitis, etc., urine examination usually occurs with occult blood. Urethritis caused by gonococcus, mycoplasma, chlamydia are sexually transmitted diseases and also belong to this category of inflammation. 2. Stones: such as kidney stones, ureteral stones, bladder stones, may cause urinary occult blood. 3. Tumors: such as benign or malignant tumors of the kidney, ureter, bladder, the patient will also have occult blood in the urine. In addition, it should be noted that female physiological period can also cause the occurrence of occult blood in urine, systemic diseases such as thrombocytopenic purpura, systemic lupus erythematosus, aplastic anemia and other diseases may also lead to occult blood in urine. Therefore, it is recommended that further examination be conducted to determine the cause of the disease, and an abnormal indicator alone cannot accurately determine the condition of the disease.