The primary purpose of the schilling test is to measure?

PGIMER Chandigarh NO - 2015

Applied Nutrition & Dietetics

Easy

Appeared in: PGIMER Chandigarh NO - 2015

Explanation

The Schilling test is a medical investigation used to determine a patient's ability to absorb vitamin B12 from the gastrointestinal tract.
It involves administering a small oral dose of radioactive vitamin B12 and then measuring the amount excreted in the urine over 24 hours.
This measurement indirectly reflects how much of the vitamin was absorbed from the intestine into the bloodstream.
The test is crucial for diagnosing the underlying cause of B12 deficiency, particularly distinguishing between pernicious anemia and other malabsorption disorders.

Option B: The test does not measure the breakdown (digestion) of vitamin B12. It assesses the subsequent step, which is the uptake (absorption) of B12 in the terminal ileum.
Option C: Vitamin B12 is an essential nutrient that is not produced by the human body. It must be obtained from external sources, primarily animal-based foods or supplements.
Option D: While the test involves measuring the urinary elimination of radioactive B12, this is only a method to infer absorption. The primary purpose is not to test the kidneys' ability to eliminate the vitamin.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic purpose of the Schilling test for Vitamin B12 deficiency as background academic context rather than a clinical decision trigger.
This test is crucial for nurses to understand as it helps differentiate the causes of vitamin B12 deficiency, primarily between pernicious anemia (lack of intrinsic factor) and malabsorption due to intestinal disease.
A key nursing responsibility during the test is ensuring the accurate and complete collection of a 24-hour urine sample, as any missed sample will invalidate the results.
Nurses must also provide patient education regarding the procedure, including fasting requirements and the importance of the urine collection process.

How to Approach the Question

First, identify the core subject of the question, which is the 'Schilling test'.
Recall or deduce the function of this specific diagnostic test. This is a factual recall question.
Analyze the options in the context of vitamin B12 metabolism. Consider the path of a nutrient: digestion, absorption, transport, utilization, and elimination.
Evaluate each option: 'Production' is incorrect as B12 is dietary. 'Digestion' is a precursor to absorption. 'Elimination' is part of the test method but not its primary purpose.
Conclude that the test uses elimination to measure how much was absorbed, making 'Absorption' the primary purpose.

Concept Tested & Keywords

Concept Tested: Diagnostic purpose of the Schilling test for Vitamin B12 deficiency.
Stem keywords: Schilling test, primary purpose, measure
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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