A high erythrocyte sedimentation rate, or sed rate, indicates an increased level of inflammation in the body, explains MedlinePlus. The test measures how quickly red blood cells in a blood sample fall to the bottom of a test tube.
A doctor usually orders a sed rate test to determine the underlying cause of unexplained fevers, muscle problems, joint problems or other vague symptoms, notes MedlinePlus. Causes of a high sed rate include pregnancy, thyroid disease, kidney disease, anemia and certain types of cancer. A normal sed rate is less than 20 millimeters per hour in women under the age of 50 and less than 30 millimeters per hour in women age 50 and older. A normal sed rate is less than 15 millimeters per hour in men under 50 and less than 20 millimeters per hour in men 50 and older.