Blood uric acid elevated to > 420 μmol / L is hyperuricemia, excessive uric acid deposition in the body can cause joints, kidneys and other tissue damage. 1. Joint damage. When uric acid is elevated, urate crystals can be directly deposited in the joints and surrounding soft tissues, which can cause joint swelling and pain, especially redness, swelling, heat and pain in the large joints of the lower limbs, and more commonly, redness, swelling, heat and pain in the big toe, which is the most common symptom of gouty arthritis. 2. Kidney damage. A large amount of urate excretion through the kidneys may cause kidney stones or gouty nephropathy, manifested by ultrasound will see multiple kidney stones, in the urine routine may find red blood cells and urinary proteins, etc., if not controlled, a large amount of urate excretion from the kidneys, may also cause renal insufficiency in the long run. Long-term high blood uric acid can cause a variety of tissue damage, it is recommended that patients with increased uric acid, such as the emergence of timely medical treatment, standardized diagnosis and treatment under the guidance of a doctor.