Pernicious Anaemia Society
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Conversion of different values re results, pls help

Hi everyone

I've just recently discovered this forum, now joined, and look forward to learning more and, hopefully, being able to contribute. However, at the moment, I am not very clued-in on PA and Vit B12, hence I have a question I hope someone will answer, please :)

In Oct 2016, along with an HbA1c test (I'm Type 2 diabetic) and, for some reason, Vit B12 and Folates was also tested. The results were rather disturbing (to me) but GP said they were OK :(

Serum Vit B12 - 165.3 ng/L [197.0 - 771.0] so noted as 'Below Range'

Serum Folate level - >20.0 ug/L [4.6 - 18.7] so noted as 'Above Range'

GP excused the high Folate level saying I must have been eating too many cabbages!!!

I asked for these tests to be repeated when due HbA1c again 3 months on (due to reduction in Diabetic medication). The results are as follows - Feb 2017

Serum Vit B12 - 199 ng/L - so now within range

Serum Folate - 17.5 ug/L - so now within range

I have a lot of symptoms which could be attributed to B12 Deficiency and so have been researching PA/Vit V12 deficiency, hence finding this forum. Much of what I've read gives levels in pg/dL, pmol/L etc but I don't know how these equate.

Perhaps someone could tell me how to convert ng/L to pg/L or pg/dL etc so that I can then give my research more meaning in relation to my levels.

Thanks very much for any help and advice


9 Replies

Hi JMN2017

Most conversions are fairly simple, but when mmol are involved you have to take into account the molecular weight of the molecule too. I don't have the link right now but do post up what you need converting and into what and I'll see if I can help.

In the meantime you could try googling " convert cortisol ng/ml to mmol/l" etc,

Good luck!

Paul Harris

Blue Horizon Medicals


Hi JMN2017 one reason why your B12 level has risen (I'm guessing) is that your "reduced medication" for Type 2 diabetes was probably Metformin which has an adverse affect on B12 levels. It would be good for this to be monitored continually along with your HbA1c tests.

Folate is essential to process the B12 and yes it comes from eating leafy green vegetables. I remember my mother shouting at me across the dinner table "Clive - eat your greens!"

I am not a medically qualified person but like you I've had Type 2 diabetes for two years and have had Pernicious Anaemia (a form of B12 deficiency) for 45 years.

I wish you well

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To convert from pmol/l to ng/l multiply by 1.355. The lower reference range for serum B12 deficiency is usually quoted at around 150 pmol/l or 200 ng/l.

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Many thanks for the above responses. I think I maybe didn't make the question quite clear, so my apologies. I'd like to know how to convert Vit B12 values in -

ng/l to pg/ml and in reverse;

ng/L to pmol/l and reverse

Thanks very much

Also, to clarify my original post a bit more, I'm still taking Metformin but have stopped taking Glipizide. I also take Levithyroxin for hypothyroidism (I understand B12 levels can also affect thyroid levels in some way)


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1 ng/L is the same as 1 pg/ml

A ng is 1000 pg and a L is 1000 ml

As Hoxo says, 1 pmol/L is 1.355 ng/ L

To do it the other way round you need to use 1/1.355 or 0.738

So 1 ng/L is 0.738 pmol/L


The various pmol/L to ng/L and vice versa above are all for B12.

For folate it is:

1 ug/L = 2.266 nmol/L

1 nmol/L = 0.441 ug/L


Thanks very much guys. I didn't know ng/L was same as pg/ml ;) So, now a bit more research and then decide what action to take ;)

Again, many thanks :)



I presume you are taking metformin for your diabetes. This can cause problems with absorbing B12 - estimate is this affects about 40% of those using it - and lead to B12 deficiency - so it is a good idea for B12 to be done iwth HbA1c.

However, not a good idea for GPs to ignore the results when they come back.

What matters in looking at the results is the ranges as even leaving aside the variation in units different assay methods tend to give different ranges ... and I never remember what the conversion factor is between the two so think I might pin this post.

Unfortunately there is a huge overlap between symptoms of B12 deficiency and those of diabetes with the result that there is a tendency to overlook the possibility that B12 is involved and dismiss everything as being down to diabetes.

As I understand it the difference between the two results isn't necessarily significant and it certainly isn't the case that being just inside the range means you are okay - the normal range for B12 and degree of variation in the general population is that just going on the range without looking at symptoms is going to result in missing 25% of people who are B12 deficient.

If your GP has done a full blood count and is dismissing the possibility of B12 deficiency because you aren't showing any signs of macrocytosis (enlarged red blood cells) then that's also fraught with problems as 30% of people with a B12 deficiency don't present initially with macrocytosis so relying on it means, again missing a large number of people who are deficient.

Please take a look through the materials in the pinned posts and try looking at a few other posts around metformin for materials that you can use to write to your GP pointing out a few facts about metformin, B12 and diabetes and see if that helps.


Thanks Gambit62

Yes, I've been taking Metformin for a few years as well as Ranitidine, also known to possibly affect the absorption of B12, so I feel I have good reason to be concerned about my B12 level. It's so frustrating when the GP just doesn't seem bothered, not even enough to suggest it worth keeping an eye on, at least.

I'll check out the pinned posts, as you suggest.

Many thanks. All advice is much appreciated



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