What does it mean to have occult blood in the urine?

Occult blood in urine, also known as hidden blood in urine, refers to the presence of red blood cells or hemoglobin released from ruptured red blood cells detected in urine tests, typically identified through microscopic examination during routine urinalysis. This phenomenon may be caused by various factors, mainly including urinary tract infections (such as glomerulonephritis, cystitis, urethritis), urinary stones (such as kidney stones, bladder stones), and kidney diseases (such as nephrotic syndrome, systemic lupus erythematosus nephritis). In addition, systemic diseases such as cirrhosis and leukemia may also lead to coagulation dysfunction, resulting in occult blood in urine. If occult blood is detected in the urine, prompt medical attention is recommended.