What is the normal range for vitamin b12?

Question by Jenn: What is the normal range for vitamin b12?
My neurologist diagnosed me with vitamin b12 deficiency. My level was barely 100. She has me giving myself b12 injections for the rest of my life.

My question is I have been sick since November with mono and cmv. And my current doctor’s are looking into fibromyalgia, which I have all the symptoms for. But why would these other doctor’s who did bloodwork not notice the low vitamin b12.

Is a level of barely 100 really low??

Best answer:

Answer by Jai
Depending on which unit of measure you’re talking about (it’s measured in pg/mL, pM, and pmol/L–from my quick glance around wikipedia), 100 is half or less of the bare minimum you should have.

There are several reasons why you may have had bloodwork that did not show a deficiency. One is that levels fluctuate. You may have gotten bloodwork directly after a large b12 intake that registered on the test as low normal levels. B12 may not have been screened in those particular workups. Lots of bloodwork doesn’t measure b12 specifically; your doctor has to ask for it specifically. With those other medical issues you had going on, it’s possible they weren’t really interested in vitamin levels–they were more interested in white blood count, etc. Or there’s also the possibility that you’ve got a sort of antibody interference.

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3 comments to What is the normal range for vitamin b12?

  • july  says:

    Normal B12 range is 200 to 600, so your results are considered low.

    The bloodwork that the other doctors did might not have included a B12 test. From reading, it’s my understanding that this is a separate lab test and not automatically included with other comprehensive lab tests such as a CBC (complete blood count) or a CMP (comprehensive metabolic panel). It seems to be a followup test ordered when other test results indicate a problem, such as a low hemoglobin (blood iron).

    B12 is stored in the liver, so it can take some time (even years) for a B12 deficiency to show up after you’ve had problems absorbing it. (Usually it’s related to lack of intrinsic factor in the stomach.)

    Mono (Epstein-Barr Virus) and CMV can certainly cause fibromyalgia-like symptoms. Or if you have fibromyalgia, EBV and CMV can make your symptoms much worse. With fibromyalgia, even one sleepless night can make your symptoms worse. I was diagnosed with fibromyalgia 10 years ago, and I have had EBV and CMV.

  • Justmeinthisworld  says:

    are your levels improved with the shots-you may test normal

    they may not have retested for b12
    you should be sure your b12 levels are normal before thinking about fibro

    you should not be considering fibro when you have other active conditions that cause pain and fatigue

    i had mono for about 10 months–but i already knew i really had fibro..you cannot make an accurate diagnosis without addressing the known condityions

    fms is highly overdiganiosed by incomeptant docs who use it as a general label for pain

  • Cindy in Texas  says:

    They probably didn’t test for vitamin levels. Those are special tests.

    I originally did B12 injections for a couple of years to manage the FMS pain. I highly suggest methylcobalamin or hydroxycobalamin & not cyanocobalamin. I noticed I only needed 5000mg a day of the methylcobalamin compared to needing twice as much hydroxycobalamin. So it was a little higher, but cheaper because it lasted twice as long.

    I have Fibromyalgia -Vitamin D3 supplementation has cleared the constant muscle pain (for the most part). I did high levels for 3 weeks & was pain free. I knocked the dose down to 2000iu’s a day & a week later the pain was back. After restarting high levels, the pain is managed again after 3 days.

    I personally did 35,000iu per day for 2 months trying to refill my stores. It is highly recommended that you have your vit.D levels tested but my research shows toxicity only at outrageous, long term levels.

    I originally did B12 injections daily for a couple of years & then I tried guaifenesin (Dr.St.Amand’s protocol) for 10 years but discovered vit.D3 supplementation only recently & that has worked better than anything else!

    Vitamin D3 is not a vitamin at all but a necessary hormone that effects the immune system & nearly every aspect of health. Having low Vitamin D levels greatly increases risk of cancer, heart disease, diabetes, MS (& maybe even FMS)

    I don’t think that FMS, cancer, MS, etc. is a vitamin deficiency but being deficient can create or greatly exacerbate health problems.

    The prescription vitamin D supplements are the wrong type (ergocalciferol ). As warned by the National Institute of Health -


    Luckily you can buy vitamin D3 (cholecalciferol) over the counter and the upper limits are extremely high. Current recommendations are for 35iu per pound – a 150# person needs minimum of 5250iu per day & the rda is 400iu. This amount is for minimal needs and does not account for depleted stores. March is when stores are at their lowest.

    Vitamin D3 deficiency is becoming an epidemic. U.S. RDA are much too low. It is possible that upper atmosphere pollution is blocking the needed UVB light from the sun.

    I also highly recommend a low carb way of eating to allow the body to regenerate rather than degenerate.


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