Mean cell volumes

[th3joker]

I've been injecting 1mg of B12 twice weekly for several years and had a recent blood test which showed high levels of B12 which is pretty normal when injecting.

They wanted to repeat the tests for another reason so I stopped the injections for 3 weeks prior to the next test.

The difference in mean cell volume was quite interesting:

Mean cell volume 99.9 fL [77.0 - 98.0]; Above high reference limit - 1st Test while injecting

Mean cell volume 133.0 fL [77.0 - 98.0]; Above high reference limit - 2nd Test 3 weeks without B12

Mean cell volume 102.0 fL [77.0 - 98.0]; Above high reference limit - 3rd Test 4 weeks later after 1mg twice a week.

[FlipperTD]

Hi Joker. I'm a scientist, not a medic, but this is my area.

MCV of 133 is fairly spectacular, but some idea of the exact timescales these results were obtained would be helpful. Likewise, some more FBC data would be helpful because there are all sorts of things that could be happening.

In health, red cells are in circulation for around 115 days, give or take a few. When red cells leave the bone marrow, [as reticulocytes] they have a higher volume than when mature, but their volume resolves to adult within a couple of days. Unless you're anaemic, you replace about 1% of your red cell mass very 24 hours, so the MCV changes, but not rapidly.

So, if you don't mind, days between measurements would be helpful, as would some more comprehensive data about the FBC, because there is always the possibility that ''something might have gone wrong' in the journey from your arm to the lab, and onwards!

I hope you're improved now, and settled!

[Narwhal10]

Great handle,

Sorry joker, without symptoms, the rationale for ordering the test, numbers with units and time scales mean nothing to me.