Question:medium
The vitamin B12 level in chronic myeloid leukemia is
The vitamin B12 level in chronic myeloid leukemia is
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Excess granulocytes raise B12-binding transcobalamins, pushing serum B12 up.
Updated On: Jun 24, 2026
- Elevated
- Decreased
- Normal
- Markedly decreased
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The Correct Option is A
Solution and Explanation
Step 1: CML is a myeloproliferative neoplasm with a massive expansion of the granulocytic series in blood and marrow.
Step 2: Granulocytes are the source of vitamin B12 binding proteins (transcobalamins I and III). With so many extra granulocytes, the circulating amount of these carrier proteins rises sharply, dragging the serum vitamin B12 concentration upward.
Step 3: This pairs with two other signature CML labs - a high LDH from rapid cell turnover and a characteristically low leukocyte alkaline phosphatase score, the latter being a key clue separating CML from a reactive leukocytosis.
Step 4: So the expected vitamin B12 level here is high.
\[\boxed{\text{Elevated}}\]
Step 2: Granulocytes are the source of vitamin B12 binding proteins (transcobalamins I and III). With so many extra granulocytes, the circulating amount of these carrier proteins rises sharply, dragging the serum vitamin B12 concentration upward.
Step 3: This pairs with two other signature CML labs - a high LDH from rapid cell turnover and a characteristically low leukocyte alkaline phosphatase score, the latter being a key clue separating CML from a reactive leukocytosis.
Step 4: So the expected vitamin B12 level here is high.
\[\boxed{\text{Elevated}}\]
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