Testing for Active B12

[humbird753]

Hi - I recently read that there is a new test for testing the active B12 level. The test is called Holotranscobalamin blood test. If this is not true, Tex, please feel free to tell me. Tks.

Paula

[Gabes-Apg]

hi Paula
I did some searching on the net but could not find anything mainstream

I did find this blog/web page and found this gents comments interesting.....
in that - if there is a new test for active B12, can we trust the results??

http://www.spacedoc.com/articles/b12-no ... le-vitamin

There are two other tests commonly used to diagnose vitamin B12 deficiency, but they also have issues:

Serum homocysteine’s results can be affected by vitamin B6 deficiency, folate deficiency, and other disorders. [1] Because of that, the test’s sensitivity and specificity are both only about 50% [3]

Serum methylmalonic acid’s results can be affected by kidney disease, thyroid disease, pregnancy or other factors. [1] In spite of that, the test’s sensitivity is a little better at about 80%, but still lags on specificity at about 60%. [3]

To further compound the confusion over testing, the test that appears to me to be the most accurate test to diagnose vitamin B12 deficiency at the cellular level, the urinary methylmalonic acid test (uMMA), is seldom ordered, and just as seldom included in studies. With a sensitivity of 100% and specificity of 99%, the test is non-invasive and is the most accurate test for seniors. [3]

I will do some more research on the weekend .....

[tex]

Paula,

I have to agree with Gabes. Holotranscobalamin has been proposed as a marker of B-12 levels for over 20 years, but as far as I am aware, no one has been able to prove (or no one has been interested in trying to prove) that it's a better marker than the currently used marker (serum cobalamin).

Theoretically at least, it seems logical that it would make more sense to measure the active fraction of the vitamin that's available to enter the cells (holotranscobalamin), than to measure the total cobalamin (B-12) level, but no one has proven this to be true, so naturally, mainstream medicine will continue to ignore it until they see rigid proof. You could tell anyone in mainstream medicine that the sun will set today at 6:25 pm (central time), but many would be suspicious of your claim unless you could point to an article published in a scientific, peer-reviewed journal describing rigid scientific proof of the claim. Simply claiming that it has happened that way since the beginning of time is not generally regarded as scientific proof.

There are at least 3 different tests available for testing holotranscobalamin levels that have been developed over the years. The most recently published medical research article that I can find on the topic was published in 2011, and the researchers concluded:

CONCLUSIONS

More than 20 y [Sic] ago, insights into the physiology of vitamin B-12 led to the suggestion that holoTC might be a sensitive marker of early vitamin B-12 deficiency. Since then, holoTC measurement has come of age. Today, we can conclude that holoTC seems more suitable than total vitamin B-12 for diagnosis of vitamin B-12 deficiency. However, to date, holoTC has not acquired wide clinical acceptance, most likely because of the test's cost and limited availability. On the basis of the data we present in this review, we predict that holoTC will also be an excellent marker for monitoring a population's vitamin B-12 status. Currently, a strong need exists for studies that can prove or disprove this prediction.

Holotranscobalamin, a marker of vitamin B-12 status: analytical aspects and clinical utility

Insurance companies, for example, apparently are not widely accepting any changes that would authorize reimbursement for B-12 testing based on holoTC. Here's an opinion from the BlueCross BlueShield of Tennessee Medical Policy Manual that was most recently reviewed/updated on October 22, 2015:

There is inadequate data to establish holotranscobalamin testing as an alternative to either total serum cobalamin, or levels of MMA or homocysteine in the diagnosis of vitamin B12 deficiency. Evidence of the clinical utility of the test is currently lacking, and therefore the test is investigational.

Serum Holotranscobalamin as a Marker of Vitamin B12 (Cobalamin) Status

IOW, it appears that the holoTC tests are valid (reliable and accurate), but no one in mainstream medicine is interested in using them, so you may not be able to receive insurance reimbursement if you use one of these tests. But that's up to individual insurance companies of course, and acceptance may vary among various policies issued by the same company, for all I know.

I hope that this is helpful,
Tex

[humbird753]

Thank you for your comments on this Gabes and Tex. As always, your opinions are appreciated.

Paula