Anaphylactic purpura occult blood XI refers to an occult blood test +/-, indicating a weakly positive urine occult blood, all other items in the urine are in the normal range, and there are 0 urinary red blood cells. Anaphylactic purpura is a systemic bleeding disorder, due to the combination of antigens and antibodies to form immune complexes deposited in the blood vessel wall, causing inflammation of the capillary and small blood vessel wall, so that the vascular permeability is increased. The kidneys are the body’s small microvessels dense organs, so when the kidneys are involved will appear hematuria, proteinuria and so on. Urine occult blood test results will be affected by many factors, therefore, urine occult blood weak positive need to be combined with other indicators to consider kidney involvement. When there is purpura nephritis and other diseases, there may be positive or strong positive urine occult blood, it is recommended to go to the hospital in time, and early under the guidance of the physician for regular treatment.