B12 or B12 active test

[hoalarg]

Hi

I'm just enquiring whether I need just the active b12 test done or both b12 and active to check my levels accurately?

One is cheaper than the other and I wasn't sure if I needed them both done or one was sufficient?

Thank you.

[ITYFIALMCTT]

Thing about the active B12 test is that if it's equivocal, you might need to pay for additional testing (MMA) on the sample so it has the potential to be more costly than it seems (depending on where it's done).

If you don't have any idea of your B12 levels then it might be enough to get a baseline with the usual test.

If you have any reason to think that you have problems relating to B12 levels then you might, over time, decide that you need to invest in the more expensive/elaborate version of the test?

[hoalarg in reply to ITYFIALMCTT]

Thank you for your reply. That's helpful.

I have never done a B12 test so doing the active version might just be a good start to see roughly where I am then.

Is active B12 a bit like Free T4 in that it's what is currently active but not not the overall amount?

[ITYFIALMCTT in reply to hoalarg]

Serum B12 is the usual test - active B12 is the more elaborate/expensive one. You're correct that the serum measures the overall level whereas the 'active' one establishes how much is bound by something else (and therefore not available for uptake by cells) so is an indication of how much is available).

I'm including the Medichecks link so that you can read more about the difference between them (I have no association with them): medichecks.com/vitamin-b12-...

[hoalarg]

I'll go for the active one then. Is it best to take the sample first thing in the morning before eating?

[Gambit62 in reply to hoalarg]

B12 stored in liver and released into blood as needed so no need for fasting,

neither serum B12 or active B12 give full picture as only measuring one step in metabolising B12 - once its in your blood it then needs to get into your cells and then once there it needs to be used by the cells.

Evaluating a potential B12 deficiency means looking at a range of indicators which could include serum/active B12, MMA/Homocysteine (will be raised if there isn't enough B12 at cell level but can also be raised as a result of other things), folate levels (folate and B12 used a lot together), full blood account (70-75% of people with B12 deficiency will have macrocytosis - larger rounder red blood cells) and symptoms

pernicious-anaemia-society....

symptoms can be a difficult one because of overlap with other conditions - including thyroid ... but they would be my starting point before thinking about testing.

lots more advice on B12 testing etc on PAS forum

healthunlocked.com/pasoc

[hoalarg]

Thanks for the informative message. That gives me a lot to go on.