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Louise Sivak, M.D.
Louise Sivak, M.D., Doctor
Category: Medical
Satisfied Customers: 3499
Experience:  Pediatrician, Board-certified in Hematology/Oncology
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Does B12 injection taken before a blood test elevate B12 serum levels?

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Can a b12 injection minutes before a blood test result in elevated b12 serum levels? I do not take any supplements, however, I have not been feeling good lately and my doc gave me an injection of b12. Blood work showed elevated levels at 1600. Now I am being referred to a haematologist.

Expert: Louise Sivak, M.D.

Hello,

No, B12 is given as an intramuscular injection, so it does not increase serum levels quickly. What other blood tests done, please? Also wondering why serum B12 was drawn after the shot just as a matter of procedure.

Customer:

Thank you for your quick response...I went into my docs office due to the fact that I have not been feeling well, fatigued, sore all the time, numbness in hands. I have had 6 flues in 2 months. I thought I had no immune system left. After my consultation, my doc thought that I may be demonstrating signs of low b12. I really had never heard of b12 before, did not know its significance. So she gave me an injection, said she does this for numerous patients feeling "down". She looked for everything in my blood, total blood count, red/white, thyroid, lyme...everything was pretty normal but my red blood cell count (low) and my b12, 1600. I did lab work the following week, same results. She said since my WBCwas in normal range she was not too worried about certain cancers. However, she wanted me to get checked out.

Expert: Louise Sivak, M.D.

We very rarely see elevated B12 levels, and most haematologists in both children and adults do not check serum B12 but rather check some other blood tests (homocysteine and others) that need normal B12 to make / function. Does your CBC show an "MCV" number? Bottom Line:you should get checked out, and if your treating physician wants you to see a haematologist, then please do. I am not worried medically about a "high" B12 because, I do not follow those levels ; I check other more reliable tests.

Was your folate level checked? Are you anaemic? (What is your haemoglobin?)

Customer:

She told me I was anaemic, let me track down my info.

MCVwas 79. The only other low miscellaneous test was vitamin d, 13 L. I am taking supplements.

Expert: Louise Sivak, M.D.

OK, I'm on call for my practice but will keep checking in periodically this evening.

OK, by my hospital's lab that MCV is low. Recommend your following with haematologist as planned ; ask him /her about B12 testing, make sure your folate gets checked. It's REALLY hard to be folate-deficient (we get it in our diet), if you eat a reasonably healthy diet (some green vegetables at least).

Yes, that Vit D is low, but low Vit D doesn't cause fatigue. Continue with the supplements as prescribed.

Customer:

I did not see a folate test, how does that correspond with b12? Sorry, I do not know much about this stuff...I have very little insurance and I know this appointment will be pricey on Thurs. I did not want to go into it if I found out an injection of b12 could cause elevated levels. Seemed like a waste

Expert: Louise Sivak, M.D.

Vit B12 and folate are both vitamins (meaning we have to get them in our diet or from a supplement - our body does not synthesize them like it does for example cholesterol). They do a bunch of things in the body including: for folate help make normal red blood cells that carry oxygen ; for B12 we know it helps a few enzymes work normally but, don't actually know a lot. Low folate and / or B12 can lead to anaemia and in the case of B12 neurologic symptoms. An injection of B12 does not cause elevated level of B12 and serum B12 measurements are clinically useless.

If I were you, I'd recheck with your primary care doctor in 3-4 weeks or sooner if you feel worse. I'm at a huge disadvantage since I do not have your records and cannot meet or examine you, but from your posted info, that's what I'd do.

Customer:

Ok, that is really what I wanted to know. I really did not want to waste my time and money for someone to just tell me the injection caused the elevation. Other than folate questions, would you suggest me asking any other questions. I want to come prepared and organized as much as possible. Is there any other tests this new doc on Thurs may require?

Expert: Louise Sivak, M.D.

S/he will have your blood counts. Your MCV is a bit low and you didn't tell me what your haemoglobin (Hgb) is? Do you eat enough iron-containing foods (red meat if you care for it, green vegetables, many foods have iron fortification but best absorption is from real foods)?

How's your diet?

Customer:

Sorry, Hgb was at 12, dietary wise I love meat of all kinds and tend to eat healthy. Hgb did not show up in bold but was considered a little low on lab tests.

Expert: Louise Sivak, M.D.

For a women of menstruating age, 12 is OK. Just try to add some more green veggies and keep up with the red meat. You're fine there.

Customer:

Ok, not going to keep you, thank you for your info, much appreciated!

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