How long does intramuscular B12 affect b12 test result?

[Needleandthread44]

Is there a length of time that it is not advised to test after having a b12 injection? My dad's last b12 injection was around 18 June. He has been taking some b12 spray since then. Would there be any point in testing for b12 now?

[Needleandthread44]

Also would it make a difference if we tested for active b12 vs serum b12? In terms of whether the b12 injection or spray would affect results (I know the serum b12 test is pretty useless)

[Nackapan]

There is no need to test.Your dad's levels should be high.

B12 stays in the blood for a long time .

Differs in individuals.

Go by his symptoms.

I recently requested my mums b12 2 monthly.

They ,despite being asked not to test did test b12 annoyingly.

Message not recieved by district nurses!

It was nearky 3 months after last b12.

To our suprise the serum b12 test was back 300+

Very low on Injections!!

Mobe 2000 on more frequent injections

Serum b12 test not useless but shows all b12 in the blood.

Does not prove if reaching cell level but s good guide for many including me.

Good if you've a baseline b12 level that you were well on.

I never had this.

We all operate at different levels.

Injection frequency shoujd be on symptoms not numbers

[Needleandthread44 in reply to Nackapan]

Thank you!

[deniseinmilden]

No, there's no point. The residual B12 from the injection, plus the spray will both give elevated levels in his blood but will not show how well his cells are taking it up and using it.

In fact, if they are absorbing it out of his blood stream poorly, it may show higher levels than if they were taking it out of the blood readily.

It is essential to go on symptoms only - this is the body's way of telling you if things need fixing.

B12 is not harmful and people can have levels which are over the testable range because they are having injections, for decades without any problems - and only benefits - so there is no point testing once injections have started.

[Needleandthread44]

Really helpful thanks

[Litatamon]

Both these links might be helpful -

stichtingb12tekort.nl/engli...

stichtingb12tekort.nl/engli...

[Needleandthread44 in reply to Litatamon]

So helpful. Thank you