[yellers]

They check blood iron levels before each donation in Australia. They send you away if you’re too low.

[ksenzee]

They check hemoglobin levels before donation in the US, but they don’t check ferritin (it’s a less commonly run test in general). You can have symptoms from iron deficiency before your deficiency is reflected in your hemoglobin level, and a ferritin test will pick that up, but a quick hemoglobin screen won’t.

[zingababba]

Yes, this is exactly what happened to me. My hemoglobin was always in range (albeit lower, but the screeners had no problems passing me along) however my ferritin was crashed.