Question about Active B12 test

[Sleepybunny]

How long can blood sample be left without results being affected before it is tested for Active b12?

What happens to Active B12 results if sample has been left for more than a day before testing eg do the levels of Active B12 decrease?

Grateful if anyone can pm me useful links.

[Jo5454]

Hi Sleepybunny

I had an Active b12 test last year. It was a postal test and I was advised by the hosp to have it taken as late in the day as possible, just prior to last post. They said it really needs to be there within 16 hours. That was impossible as it was taken about 4.15 and I was pretty sure it wouldn't have arrived and be tested by 8.15 next day, so I guess there's room in it? It was through St Thomas, who do a MMA test with the same sample if required, so again it could be that the time limit is more for that than Active part of the test? It could vary depending on where it's done I guess.

I really don't know if levels decrease, have you had the test and concerned with the results?

[Sleepybunny in reply to Jo5454]

Thanks, just wanted to know as someone asked me.

[Foggyme Administrator]

Hi Sleepybunny.

Here's something I found about Active B12 (holotranscobalamin) test:

'HoloTC, like vitamin B-12, is a stable analyte and no special precautions need to be taken to draw blood samples for holoTC measurement. HoloTC is also stable in storage at –20°C to −70°C, probably for years. Loikas et al (28) examined stability systematically for storage at –70°C for up to 16

'

ncbi.nlm.nih.gov/pmc/articl...

👍

[Sleepybunny in reply to Foggyme]

Thanks for that link Foggyme.