In iron studies, if UIBC = 185 µg/dL and Serum iron = 125 µg/dL, what is the % transferrin saturation?

In iron studies, if UIBC = 185 µg/dL and Serum iron = 125 µg/dL, what is the % transferrin saturation?

• A. 30.0%
• B. 40.3%
• C. 50.0%
• D. 60.0%

Answer: (B)

Transferrin saturation measures how much iron-bound capacity of transferrin is used, calculated from serum iron relative to the total iron-binding capacity (TIBC). TIBC is the sum of serum iron and unsaturated iron-binding capacity (UIBC). Here, TIBC = 125 + 185 = 310 µg/dL. Then transferrin saturation = (serum iron / TIBC) × 100 = (125 / 310) × 100 ≈ 40.3%. So the percent transferrin saturation is about 40.3%. This sits in the typical range (roughly 20–50%), indicating normal iron availability rather than deficiency or overload.

Transferrin saturation measures how much iron-bound capacity of transferrin is used, calculated from serum iron relative to the total iron-binding capacity (TIBC). TIBC is the sum of serum iron and unsaturated iron-binding capacity (UIBC). Here, TIBC = 125 + 185 = 310 µg/dL. Then transferrin saturation = (serum iron / TIBC) × 100 = (125 / 310) × 100 ≈ 40.3%. So the percent transferrin saturation is about 40.3%. This sits in the typical range (roughly 20–50%), indicating normal iron availability rather than deficiency or overload.