A Schilling test may be ordered for a patient suspected of which condition?

The Schilling test is specifically designed to evaluate vitamin B12 absorption and to assist in diagnosing pernicious anemia. In this condition, the body is unable to properly absorb vitamin B12 due to a lack of intrinsic factor, which is produced by the stomach lining. The test involves administering radioactive vitamin B12 and measuring its levels in the urine after a specific period. If the body cannot absorb vitamin B12 due to intrinsic factor deficiency, it will result in low levels of B12 in the urine, confirming the suspicion of pernicious anemia.

The other conditions listed do not directly relate to vitamin B12 absorption issues. Hemolytic anemia involves the premature destruction of red blood cells, multiple myeloma is a type of blood cancer that affects plasma cells, and iron deficiency anemia is due to insufficient iron, not vitamin B12. Therefore, the Schilling test is not applicable to these conditions, making it clear why pernicious anemia is the correct choice.