Transferrin Saturation Calculator

Transferrin saturation (TSAT) measures the percentage of transferrin binding sites currently occupied by iron ions. The primary calculation divides your serum iron concentration by the total iron-binding capacity (TIBC), expressed as a percentage: Saturation = (Iron / Capacity) * 100. Alternatively, if measuring transferrin directly in milligrams per deciliter, a secondary formula is utilized: Saturation2 = (Iron2 / Transferrin) * 70.9, which accounts for the molecular weight ratio and standard binding capacity of transferrin molecules.

Imagine a patient receives a standard iron panel yielding a serum iron concentration of 90 mcg/dL and a total iron-binding capacity (Capacity) of 300 mcg/dL. Using our formula, we divide the serum iron by the capacity: 90 / 300 = 0.30. Multiplying this decimal by 100 gives a transferrin saturation of 30%. This falls safely within the normal healthy range, indicating that roughly one-third of the body's iron-transport proteins are actively carrying iron.

Always interpret your transferrin saturation alongside a complete iron panel, including ferritin and complete blood count (CBC), to get a full picture of your body's iron stores. Because serum iron levels fluctuate throughout the day and can be impacted by recent meals or inflammation, fasting morning blood draws are typically recommended for the most accurate baseline readings.