A 58-year-old woman has a gastric ulcer, achlorhydria, and vibration sense loss in the lower extremities. She has a megaloblastic anemia. What test would help support a diagnosis of pernicious anemia?
The Schilling test is performed by giving radiolabeled B12 orally (after saturating the B12 stores by intramuscular B12 ). In pernicious anemia, less than 3% of the label is found in the 24-hour urine collection (N>7%). Hemoglobin electrophoresis will detect defects in a- or b-globin chain synthesis, as seen in thalassemia (Mediterranean anemia).
Response to injection of radioactive B12
Endoscopic retrograde cholangiopancreatography (ERCP)
Prothrombin time (PT)
Radiolabeled B12 given orally
Stomach & Duodenum