Hi @marciahudson6661, welcome to Mayo Connect. While we are backed by the Mayo Clinic, the members in the forum are people just like you who join in to find answers from other members with our shared experiences. We’re not medical professionals so we can’t diagnose or offer treatments. If you’d like to have an appointment with one of the specialists in the clinic, here is a link for you to request an appointment. http://mayocl.in/1mtmR63

Having Vitamin B-12 levels as elevated as what you’re seeing is excessively high. There isn’t a known toxicity if there is too much in the blood. But often, when there is an increase level of B-12 in a blood test, it can actually point to a condition where the blood cells aren’t absorbing the vitamin which can cause anemia; Explaining the fatigue. It feels counterintuitive but B-12 supplements are then prescribed for that condition.

Do you have any signs of a B-12 deficiency such as tingling in the hands and feet, problems with balance, a racing heart, confusion, memory issues, weakness, loss of appetite?

Having a B-12 serum reading over 20,000 could signal a serious underlying illness. May I ask what types of tests have been done for you? The serum test measures the b-12 in your blood stream but it doesn’t tell you how much of the vitamin is actually being used or if you’re deficient. There’s a blood test called MMA (Methylmalonic acid) which can tell if your body can utilize the B12 floating around in your bloodstream.

Are you seeing any other abnormalities in your blood numbers such as too many white blood cells, large red blood cells with an flagged MCV on your chart or low hemoglobin?

I’m sure this has to be incredibly frustrating for you! How long has this been going on?