We said more than once how we would like to see the active-B12 test (or, to a lesser extent, the MMA test) become the first-line diagnostic tool at hospitals. To show how useful it could be, here are a number of anecdotes and case reports that Axis-Shield Diagnostics, developers of the active-B12 test, described on their website.
Active-B12 Case Studies
Haptocorrin Deficiency Leading to Low Total-B12
In the first case, patient showed total-B12 levels of 98pmol/L and appeared to have B12 deficiency. However, he had no clinical symptoms like anemia, macrocytosis, neuropathy, or high levels of homocysteine or MMA. An active-B12 test then revealed levels of 46pmol/L, indicating that his true, bio-available B12 stores were replete.
Apparently, he had a partial deficiency of haptocorrin of no clinical consequences. His low total-B12 levels led him to go through several follow-up tests, incurring added cost and inconvenience, while a single active-B12 test would have given a conclusive result.
In a second case, an 89 year-old patient showed up with a sense of confusion, and with macrocytosis. B12 deficiency was presumed. Total-B12 levels were 114pmol/L. However, active-B12 was 99pmol/L, indicating healthy B12 status. Like in the previous case, it was concluded that his low total-B12 levels were due a deficiency in haptocorrin, causing low holohaptocorrin (inactive-B12) levels. Dr. Ralph Carmel suggests that up to 15% of patients with low levels of B12 may have a mild haptocorrin deficiency.
Low Total-B12 During Pregnancy
In this third case, patient was 38 weeks pregnant and was tested for B12 deficiency after complaining of numbness. Total-B12 levels were 77pmol/L, indicating a severe lack of B12. Immediately, pernicious anemia was suspected, perhaps due to its very serious implications. However, an active-B12 test showed sufficient levels of 43 pmol/L.
In pregnancy, total-B12 levels drop, but it’s due to falling levels of inactive B12 (holoHC). Active-B12 (holoTC) remains mostly unchanged. The active-B12 test showed that the patient’s true B12 levels were normal. Her numbness was due to something else.
Hypothyroidism & B12 Deficiency
The fourth case shows an 87 year-old patient with shortness of breath and anemia. His hemoglobin was low, MCV was normal, and TSH was high – pointing to hypothyroidism. His total-B12 levels were 170pmol/L, indicating sufficiency (by most hospitals, though not by us). Normal RBC folate and serum folate levels indicated that his iron status was normal and the anemia was presumed to be due to the hypothyroidism.
However, his active-B12 concentration was only 4pmol/L, indicating a most severe vitamin B12 deficiency. Hypothyroidism patients can have this discrepancy between total and active-B12 levels. In this case, the active-B12 test would have saved time, revealing the severe deficiency immediately, allowing to start treatment right away.
Hematological Disorders Confounding B12 Status
The fifth case brings a 87 year-old patient suffering from non-Hodgkin’s lymphoma. She was severely anemic, with high RDW and low MCV, indicating microcytosis. However, there was no reason to be microcytic, because ferritin levels were very high. Total-B12 levels were also high, at 373 pmol/L, so patient appeared to be B12-replete.
However, an active-B12 test revealed her severe B12 deficiency, at only 12 pmol/L. So even though her blood levels of total-B12 looked normal, she was totally deficient. Abnormalities in carrier proteins are evident in many hematological disorders, in this case affecting B12 transport and confounding the regular B12 blood test.