Transferrin saturation above 45 percent: what a high result means

How it works

A transferrin saturation above 45 percent is the threshold the AASLD haemochromatosis guideline uses for further evaluation, with EASL 2022 using above 45 percent for women and above 50 percent for men alongside a raised ferritin. Saturation is the key discriminating test on the high side of iron, because ferritin rises with inflammation for reasons that have nothing to do with iron loading, while a genuinely high saturation points at iron itself.

Saturation also swings with recent iron intake and time of day, so guidance advises confirming an elevated result with a second, fasting sample before anything else.

Guideline positions

BSG 2021 reads transferrin saturation alongside ferritin: a saturation below 20 percent alongside a ferritin of 30 or more is consistent with iron deficiency even where the ferritin looks acceptable, and saturation is more reliable than ferritin where inflammation is active. At the other end, the AASLD haemochromatosis guideline sets a saturation above 45 percent as the threshold for further evaluation, with EASL 2022 using above 45 percent for women and above 50 percent for men alongside a raised ferritin, and both advise confirming an elevated saturation with a second, fasting determination before anything else.

Practical framework

This one suggests a conversation with your GP, starting with a repeat fasting sample. A confirmed high saturation alongside a raised ferritin is the pattern that routes to genetic testing for hereditary haemochromatosis, which is common enough in people of Northern European descent to be worth taking seriously, and this suggests holding off on any iron until it is assessed.

You can read your own numbers against these thresholds with the free blood test result interpreter on this site. It runs entirely on your device, nothing is saved, and pasting your report fills the values in for you.