1/6 - The Mystery
A patient presents with a serum B12 level above assay.
And yet, the clinician strongly suspects the patient has B12 deficiency.
🤔How might this occur?
A patient presents with a serum B12 level above assay.
And yet, the clinician strongly suspects the patient has B12 deficiency.
🤔How might this occur?
2/6 - A Solution
💡Myeloproliferative disorders (e.g., CML, PV, ET) can lead to high B12 levels despite tissue level deficiency.
💡Myeloproliferative disorders (e.g., CML, PV, ET) can lead to high B12 levels despite tissue level deficiency.
3/6 - An Explanation
📝The abnormal cells in myeloproliferative disorders secrete haptocorrin. When B12 binds haptocorrin it is less efficiently removed from the body.
Result: increased serum B12 levels
pubmed.ncbi.nlm.nih.gov
📝The abnormal cells in myeloproliferative disorders secrete haptocorrin. When B12 binds haptocorrin it is less efficiently removed from the body.
Result: increased serum B12 levels
pubmed.ncbi.nlm.nih.gov
4/6
But, haptocorrin-bound B12 is stuck in the plasma and cannot be utilized by cellular machinery.
Result: effective B12 deficiency, despite a normal or even increased serum B12 level
sciencedirect.com
But, haptocorrin-bound B12 is stuck in the plasma and cannot be utilized by cellular machinery.
Result: effective B12 deficiency, despite a normal or even increased serum B12 level
sciencedirect.com
5/6
One study of 33 patients with myeloproliferative disorders found that 27% had occult vitamin B12 deficiency due (i.e., normal/elevated serum B12 levels with increased MMA levels).
pubmed.ncbi.nlm.nih.gov
One study of 33 patients with myeloproliferative disorders found that 27% had occult vitamin B12 deficiency due (i.e., normal/elevated serum B12 levels with increased MMA levels).
pubmed.ncbi.nlm.nih.gov
6/6 - Postscript
Myeloproliferative disorders are not the only conditions that can lead to elevated B12 levels.
In one review, the conditions most associated with very high B12 values were:
➤Alcohol use disorder
➤Liver diseases
➤Cancer
ncbi.nlm.nih.gov
Myeloproliferative disorders are not the only conditions that can lead to elevated B12 levels.
In one review, the conditions most associated with very high B12 values were:
➤Alcohol use disorder
➤Liver diseases
➤Cancer
ncbi.nlm.nih.gov
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