The Schilling test is used to detect defects in the absorption of which vitamin?

The Schilling test is specifically designed to assess the absorption of cyanocobalamin, also known as vitamin B12. This test is particularly useful in diagnosing conditions such as pernicious anemia, which occurs due to a deficiency of intrinsic factor necessary for vitamin B12 absorption, or other disorders that affect the gastrointestinal tract's ability to absorb this essential nutrient.

During the Schilling test, a patient's ability to absorb a radioactive form of vitamin B12 is evaluated. If the patient cannot absorb this vitamin adequately, further investigations can pinpoint whether the cause is related to a lack of intrinsic factor, intestinal malabsorption, or other issues affecting B12 absorption.

Other options like fatty acids, pyridoxine (vitamin B6), and iron are not the focus of the Schilling test, making them unrelated to the specific absorption issues that this test aims to analyze.