Pernicious Anaemia Society
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Low but normal B12 and Folic Acid - Symptoms! HELP!

Just got my NHS blood test results back and frustratingly the results of B12 and Folate are JUST within the normal range. They are as follows:

Serum vitamin B12 level 203 ng/L [197.0 - 771.0]

Serum folate level 4.9 ug/L [3.89 - 26.8]

Yet I am still having serious symptoms: daily nausea, dizziness, constipation, lack of appetite etc.

Doctor says results normal and so will only prescribe medication for constipation. Any advice?

4 Replies

I'm not the best to answer as I'm still learning about this myself. Others with more knowledge will answer but in the meantime are you supplementing b12?

I was prescribed injections when my levels were 238. I used blue horizon for the test who's ranges state (<140 deficient) (140-250 insufficient) (>725 consider reducing dose)

I've also been advised on here that neurological symptoms can be experienced under 500.

It might be worth supplementing yourself to see if you get any improvements and retest to see if it makes a difference to your levels. If not you could go back to your gp with the evidence to argue that you might have an absorption problem.

I think if you go on the PA website or some of the pinned posts on here will have evidence that your levels should be higher so you could take it to show your gp. Otherwise try a different gp x

1 like

serum B12 is a difficult test to take as a single measure - variation in way serum levels relate to what is happening in cells is such that the test misses 25% of those who are B12 deficient but also picks up 5% who aren't. Having levels as low as you do means there's quite a good chance you could be in the 25% that gets missed.

clarifying test would be homocysteine and MMA but may be difficult to get your GP to agree to this.

suggest you write to GP with details of symptoms and problems with the serum B12 test (reference would be the BCSH guidelines on cobalamin and folate deficiencies and then follow up with an appointment.



Flowchart from BSH Cobalamin and Folate Guidelines

Flowchart above makes it clear that in UK, people who are symptomatic for B12 deficiency should have an IFA Intrinsic Factor antibody test and start initial b12 treatment. This applies whether b12 is low or within range.

Some of my GPs were unaware of the BSH Cobalamin and Folate Guidelines so I gave them a copy.

Lists of B12 deficiency Symptoms

I ticked all my symptoms on PAS list and gave copy to GPs.


B12 books

"What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

"Could it Be b12" by Sally Pacholok and JJ. Stuart

B12 websites



PAS tel no +44 (0)1656 769 717

B12 Deficiency Info

Link about writing letters to GPs about B12 deficiency

Other B12 info

BMJ B12 article

Emphasises the importance of treating symptomatic patients even if tests do not show a clear deficiency

I am not medically trained just a person who has struggled to get a diagnosis.


eat chicory


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