Which equation correctly estimates TIBC in ug/dL from transferrin measured in mg/dL?

• A. Transferrin (mg/dL) × 0.07
• B. Transferrin (mg/dL) × 0.7
• C. Transferrin (mg/dL) × 0.007
• D. Transferrin (g/dL) × 0.07

Answer: (A)

TIBC is a measure of how much iron-binding capacity is available in the blood, which is tied to how much transferrin is present. Since transferrin concentration is given in mg/dL and TIBC is in μg/dL, the relationship is a simple proportional one with a conversion factor that accounts for units and how much capacity each mg of transferrin provides. Using Transferrin in mg/dL multiplied by 0.07 gives TIBC in μg/dL in this estimation scheme. The other options either mix up units (like using g/dL or different scales) or apply a factor that doesn’t align with the unit conversion needed for this pairing of measurements, so the 0.07 factor is the appropriate quick estimate.