Reactive arthritis, formerly referred to as Reiter's syndrome, is a form of arthritis that affects the joints, eyes, urethra (the tube that carries urine from the bladder to the outside of the body), ...

Reactive hypoglycemia, also known as postprandial hypoglycemia, is low blood sugar that occurs a few hours after eating a meal. It is a rare condition that occurs when a person has too much insulin in ...

The hepatitis A virus (HAV) antibody (AB) total test identifies both types of antibodies that the body produces in response to HAV infection. A reactive result means the test has detected HAV ...