I get labs drawn probably at least 5 times per year, and get about 8 tubes drawn each time. I’m pretty sure that my ferritin is on the lower side due to getting labs done too frequently. Could possibly be a methylation issue. I plan on getting 23 and me done at some point to find out. But I honestly think it’s just due to getting labs drawn too often. I don’t take NAC or turmeric. Didn’t know NAC blinded to iron, but I was aware about turmeric, and purposely avoid it for that reason. And ya RBC, HCT and HGB are all good.
Highly doubtful even when having 8 tubes drawn each time that this small amount of blood loss is lowering your ferritin.
Donating for sure as 500 ml of blood is being drawn!
*If you need a lot of tests therefore, you could end up having about 30 ml of blood (about six medicine teaspoons) taken out of your arm.
How much blood is normally taken?
This depends on the sort of tests you are having done. Many tests can be done on the same sample of blood so you do not need to have a single bottle for each one: The bottles do not necessarily have to be completely filled either.
- Purple bottle - 3 ml - used for a full blood count (FBC) and ESR. An FBC needs 1 ml; a full 2.5 ml is needed if an ESR is also performed.
- Yellow bottle - 2.5 ml - this is used for a lot of different chemical tests, so it is usually completely filled.
- Other less common tests come in bottles up to 6 ml in volume and blood culture bottles are the largest size at 10 ml.