Which blood tests are most helpful when cost is an issue please?

[Bunny12345678]

I've been pricing up the IF, MMA and homocysteine tests and can only really afford one, maybe two if absolutely essential.

I previously had an active B12 result of 123 (25.1-165.0) last week (venous sample), and total B12 280 (capillary sample).

[Bunny12345678]

I'm not sure either, I believe that you're best to be off supplements a few days prior to testing though

[Bunny12345678]

I agree 👍

[Gambit62 Administrator]

I would save your money and not do any of the tests -

your active B12 result was very good which would suggest that B12 deficiency/ a B12 absorption problem isn't part of what is going on.

I know that TUK seems to have this thing about B12 levels needing to be at top of the range but I think that comes from people looking at what happens in patients with B12 absorption problems who have been treated with injections.

The normal range for serum B12 is etremely large - as is the active range

Your body naturally regulates serum B12 levels by using stores in the liver so that for any individual you would expect them to be pretty constant at the point that is right for them but that could be anywhere in the range which is what makes it so difficult to interpret serum B12 as a single test. It is also only accurate to about 20% but that would still put your serum B12 result well in the normal range.

If you have a B12 absorption problem, this also affects the ability to regulate serum B12 levels which means that serum b12can be a useful test if looking at trends over time and seeing a steady drop, or a significant drop (>20%) between two tests.

[fbirder]

As Gambit62 says, you do not have a B12 absorption problem as your Active B12 is not only way above the bottom of the range, it is quite a bit above their grey area. You have lots of active B12 in your blood.

It is possible, extremely unlikely but possible, that you may have a functional deficiency - where there is plenty of B12 in the blood, but it's not getting into the cells. You can test for this using an MMA test which isn't too expensive.

But it's unlikely to tell you anything useful. Your symptoms do not sound like those expected from a B12 deficiency.

[Bunny12345678 in reply to fbirder]

But I do have all the neurological symptoms.

[fbirder in reply to Bunny12345678]

You've not mentioned them in previous posts -

I have tinnitus, shortness of breath, fatigue, bowel problems, pleuritic aches, raynauds

Shortness of breath, pleuritic aches, head fog, palpitations,

feeling ghastly and faint, palpitations and shortness of breath, I now have aches in my neck, above right breast and posterior right rib ache. My legs feel like jelly and head foggy plus tinnitus, bowels also not normal.

I have many, i started in December with shortness of breath and palpitations. I was near collapse many times during Dec and January, ended up in a&e twice and sent away being told everything 'normal '! I felt ghastly. I developed upper right sided back ache,upper right chest ache/pressure, right neck ache...tinnitus, feeling freezing quite often, extreme fatigue, new raynauds to fingers, now have lower back ache too, bowels are not right at all, my legs feel like jelly... i just feel ill

No mention at all of pins and needles/tingling/numbness is fingers and toes. No mention of balance problems or clumsiness. No neuropathic pain. No vertigo or dizziness.

Indeed, it seems that, of the neurological symptoms listed by the PAS - pernicious-anaemia-society.... - you have one. And a lot of people have tinnitus without a B12 deficiency.

So I stick with my comment - your symptoms do not sound like those of a B12 deficiency.

[Bunny12345678 in reply to fbirder]

Yes i do have neurological symptoms, i have not listed all my symptoms as I'd never finish typing...but yes I have tinnitus, leg weakness, dizziness, feeling faint, burning feet, altered bowels, sleep disturbance, hair loss, menstrual problems, breathlessness, chronic fatigue, muscle twitching, palpitations.

[Bunny12345678]

Exactly, I have been advised by a few people to pursue this, that's why I was asking for advice on tests.

[Bunny12345678]

I agree, I've been doing a lot of reading about it, I'm no expert, but like you say, the tests that are out there are not all 100%, that's why I just wanted to know which one's are the most accurate and preferable, and also one's that a dr cannot ignore. I've managed to uncover that I have a high MCV level which is indicative of macrocytosis which is caused by B12 deficiency, so I know I'm not wrong to investigate further, especially as I'll been so unwell.

[fbirder]

£60 - for a test that does serum B12, Active B12 and MMA. Doesn't sound expensive. Not compared to any other test.

nutris.viapath.co.uk/pages/...

[fbirder]

It depends on why you're taking the test to find out.

If you think that you have a functional deficiency, where you have lots of B12 in the blood, but it's not getting into the cells, then carry on injecting.

If you want to prove that you would have a deficiency if you hadn't been injecting then you'll need to wait several months.

However, if you've only been injecting for a week then I would carry in injecting and wait for a couple of months. If the injections haven't helped with your symptoms then you either have a functional deficiency (in which case do the MMA test) or your symptoms aren't caused by a B12 deficiency.

[fbirder]

No.

B12 is too big to pass through biological membranes without help. That's why it needs the Intrinsic Factor protein to carry it across the gut wall into the blood, and why it cannot be absorbed 'passively' in the gut, across the skin, or sublingually.

It also means that B12 cannot just pass passively into cells from the bloodstream.

B12 in blood is bound to one of two proteins - haptocorrin (HC) or transcobalamin (TC). Nobody knows, for sure what the use of HC- B12 is, even though 80% of your B12 is in that form. TC-B12 is what is called 'Active B12'. Only TC-B12 can enter the cell.

Cells have a special receptor that grabs hold of TC and drags it inside the cell. It also takes the B12 with it. Once inside the cell the TC is removed and so is the top ligand (the methyl, hydroxo, adenosyl, or cyano bit) leaving behind cob(II)alamin. That is then shipped off to the bits of the cell that need B12.

Any of the processes described can be faulty. It may be that your body doesn't make much TC (but that would be picked up in an Active B12 test). It may be that the receptors for TC don't work properly. It may be that the TC isn't removed properly. It may be that the enzyme that removes the top ligand, or the transporter protein in the cell, don't work.

All of those can caused a functional deficiency, Most will be difficult to diagnose.

[fbirder]

Yup. It certainly sounds as if you have an absorption problem. And the most common is PA.

[Gambit62 Administrator]

Bunny12345678 if you have neurologocial problems you should ask for a referral to a neurologist as there are a large number of causes of neurological problems and B12 is only one of them.

I would still advise you to safe your financial resources as there aren't any conclusive tests you could do - the ones that you have done so far aren't actually pointing at B12 as the problem - and GPs may not necessarily pay any attention to private tests.

If I remember your blood results they were showing results that were within the normal range rather than results that clearly indicated macrocytosis and the only way that macrocytic tendencies could be confirmed would be comparing results to show an upward trend in size.

[Bunny12345678 in reply to Gambit62]

Thankyou for your reply. I've applied for all of my gp test results so I can compare. I had a raised mcv on the results that I did, so who knows whats up with me??

[fbirder]

There are other possibilities. Coeliac's is one, Crohn's another. A gastroenterologist would be best placed to decide. If you really want to know a gastroscopy, with biopsy samples, will tell. They're not as bad as you might thing. I had my eighth two weeks ago.