Why B12 Blood Tests are an Epic Fail
This may come as a shock, but your vitamin B12 blood test was probably inaccurate. Because they count total vitamin B12, as opposed to specifically active B12 levels, serum vitamin B12 testing fails to give a true diagnosis. As a result, you may have received a positive result when, in reality, you may still have vitamin B12 deficiency.
What is active B12?
Active vitamin B12 is cobalamin that has bound itself to the protein transcobalamin (TC), forming a vitamin B12 complex known as holotranscobalamin (HoloTC), or active vitamin B12.
Active vitamin B12 is the only type that your body is able to access and use for neurological health, energy production, and red blood cell distribution.
A deficiency in active vitamin B12 is what causes symptoms like brain fog, painful tingling and numbness, depression, and chronic fatigue.
Unfortunately, active vitamin B12 has a very short life expectancy…
What is inactive B12?
Not all cobalamin you consume is usable. When cobalamin binds itself instead to haptocorrin (HC), it becomes HoloHC, a B12 complex that lacks cellular receptors, making it a passive, or inactive, form of vitamin B12. Your body is unable to make use of HoloHC outside of the liver.
There are no reported symptoms of a deficiency in HoloHC.
Roughly 70-90% of cobalamin in your body is comprised of inactive vitamin B12 (HoloHC).
Looks can be deceiving
According to standard B12 testing, anybody with less than 148pmol/L (200pg/mL) of vitamin B12 in the blood is diagnosed with vitamin B12 deficiency. Regardless of the absence of symptoms indicating vitamin B12 deficiency (tiredness, memory loss, tingling in the hands and feet), you will be told that you have vitamin deficiency if you don’t meet this threshold.
According to this study on vitamin B12 screening that is exactly what happens in many cases; a significant number of people tested for vitamin B12 deficiency received a positive diagnosis because their total vitamin B12 levels were low, even though they exhibited none of the telltale symptoms. This may be called a “false positive,” because in reality, their active vitamin B12 levels might have been normal.
The opposite is also true; a B12 blood test result indicating normal cobalamin levels does not, in reality, confirm the absence of vitamin B12 deficiency. Because standard B12 testing only tests for total cobalamin, as opposed to usable (active) cobalamin, one can have all the symptoms of vitamin B12 deficiency or pernicious anemia without ever receiving a diagnosis…or treatment.
Scientists estimate that half of all people who suffer from vitamin B12 deficiency do not receive treatment, because of false B12 test results.
Will the real B12 please stand up?
Only by testing for active vitamin B12 in the blood can doctors efficiently and accurately diagnose vitamin B12 deficiency, as indicated in this study on Holotranscobalamin levels in patients with B12 deficiency.
In scientific studies proving that vitamin B12 delays the onset of Alzheimer’s disease, scientists tested for active vitamin B12, HoloHC, not total B12 levels.
Too little, too late
Because of current methods of testing for vitamin B12 deficiency, you are not likely to receive treatment until you start experiencing the signs, and damage, linked with insufficient vitamin B12 levels. This is tragic, because nerve cells lost to B12 deficiency can never be recovered in its advanced stages. Also, until active vitamin B12 levels are restored, you are at an increased risk for heart attack and stroke.
Go with your gut
Currently, testing for active vitamin B12 is not the norm. If you believe that you have vitamin B12 deficiency, but your doctor doesn’t, you have a few options.
- Refer to the vitamin B12 deficiency symptoms checklist, and ask your doctor to prescribe vitamin B12 shots, even if your B12 blood tests came back normal.
- Seek another doctor’s advice.
- Visit a neurologist.
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