TF and Iron deficiency anemia: Of 2711 patients, 618 (22.8%) were iron deficient (= transferrin saturation [TSAT] < 16%) preoperatively, 173 (6.4% of the cohort) had an absolute iron deficiency (AID; TSAT < 16% and ferritin < 30 μg/L) and 445 (16.4%) had functional/mixed ID (TSAT < 16% and ferritin ≥ 30 μg/L).