The Kleihauer–Betke ("KB") test, Kleihauer–Betke ("KB") stain, Kleihauer test or Acid elution test, is a blood test used to measure the amount of fetal hemoglobin transferred from a fetus to a mother's bloodstream.[1] It is usually performed on Rh-negative mothers to determine the required dose of Rho(D) immune globulin (RhIg) to inhibit formation of Rh antibodies in the mother and prevent Rh disease in future Rh-positive children.[2] It's named after Enno Kleihauer and Klaus Betke who described it in 1957.









