Testint for B12

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Hey, can anyone tell me if the HoloTc test and the MMa Urine test are

really worth doing in order to check the true b12 levels being absorbed by the body?


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  • Posted

    Serum cobalamin currently remains the first-line test, with additional second-line plasma methylmalonic acid to help clarify uncertainties of underlying biochemical/functional deficiencies.

    Serum holotranscobalamin has the potential as a first-line test, but an indeterminate ‘grey area’ may still exist. Plasma homocysteine may be helpful as a second-line test, but is less specific than methylmalonic acid. The availability of these second-line tests is currently limited.

    Methylmalonic acid is a chemical used up in one of the cellular reactions mediated by B12. If there's not enough B12 in the cell then MMA levels will rise. If they're not high then it means your cellular levels of B12 are OK. High levels of plasma MMA (>0.75umol/L0 almost invariably indicate cobamalin deficiency.

    The uMMA test measures the amount of MMA in the urine or blood.  Elevated levels of MMA indicate B12 deficiency.  MMA is 40 times more concentrated in the urine than the blood, and the urinary MMA  (uMMA) is the preferred test over the serum MMA.

    The new BCSH guidelines say: “Plasma tHcy and/or plasma MMA, depending on availability, may be considered as supplementary tests to determine biochemical cobamalin deficiency in the presence of clinical suspicion of deficiency but an indeterminate serum cobamalin level”.

    I am not a medically trained person but I've had Pernicious Anaemia (a form of B12 deficiency) for more than 46 years.

    I wish you well.

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  • Posted

    Thank you so much for the explain Clive! The B12 serum test I've done came very high last time I did it. I was considering these two, but the MMa is very expensive.

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