有關 Schilling test 的敘述，下列何者最適當？

` tag and follow all sections. "現行新政策比較" might not be applicable directly as a policy, but I will mention under clinical significance/policy that the test is commercially obsolete/discontinued worldwide due to modern serological alternatives. This serves as a temporal context for the exam question.

Wait, check Option D again. "數值低於限值表示患者腸道微生物製造維生素B 12不足" Low value means patient's intestinal microbes don't make enough B12. This is blatantly false, as humans don't absorb B12 produced by their own colon microbes anyway. The B12 we need must come from diet. The test measures absorption of dietary

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