Blood is routinely drawn from newborn infants for testing. Blood is obtained by "heel stick" and collected on a special blotter paper. Routine testing includes phenylketonuria and blood type. Many hospitals include other tests such as thyroid function, hemoglobin S (sickle cell disease), or may test for other blood disorders (hemoglobinopathies). Testing can be tailored to the local population, taking into account race and ethnic background in determining what routine testing should be done.