Normalize serum iron and iron-binding capacity units and calculate transferrin saturation.
Use iron and capacity values from the same panel.
Educational estimate only. It is not medical advice, a diagnosis, or a substitute for assessment by a qualified healthcare professional. Ferritin, inflammation, laboratory ranges, symptoms, and clinical context also matter.
This transferrin saturation calculator divides serum iron by total iron-binding capacity and expresses the result as a percentage. It can normalize several mass-concentration units before forming the ratio.
Transferrin saturation is one part of iron studies. It must be interpreted with the laboratory’s reference interval, ferritin, blood count, inflammation, symptoms, medical history, and collection conditions. It cannot diagnose iron deficiency or overload by itself.
Both measurements should come from the same specimen or compatible collection time. The page converts each to micrograms per decilitre before division.
Transferrin saturation (%) = serum iron ÷ TIBC × 100
When both values already use µg/dL, no conversion is needed. Because this is a ratio, equivalent units cancel. TIBC must be greater than zero.
| Term | Meaning |
|---|---|
| Serum iron | Measured circulating iron concentration. |
| TIBC | Total iron-binding capacity reported by the laboratory. |
| TSAT | Calculated percentage of binding capacity occupied by iron. |
| µg/dL | Micrograms per decilitre, the common normalized unit here. |
| Reference interval | Laboratory-specific comparison range, not a universal cutoff. |
For serum iron of 80 µg/dL and TIBC of 320 µg/dL, transferrin saturation is 80/320 × 100 = 25%.
If iron is entered as 0.8 µg/mL, conversion multiplies it by 100 to obtain 80 µg/dL, producing the same percentage with TIBC 320 µg/dL.
The result states the fraction of reported binding capacity represented by serum iron. It is not the percentage of all body iron and does not directly measure iron stored in tissues.
Serum iron can vary with time of day, recent intake, supplements, illness, and collection conditions. Follow preparation instructions from the ordering service and interpret repeat results under comparable conditions.
Low values can occur in more than one clinical setting, including iron deficiency and inflammatory states. High values also have multiple possible causes. Ferritin and other findings help place the number in context.
Reference intervals and decision thresholds differ by laboratory, population, and clinical question. Use the units and flag printed on the original report rather than applying an unrelated range from the internet.
Unit selection is critical. A factor-of-one-hundred or larger error can still produce a plausible-looking percentage when only one input is converted incorrectly. Copy both numerical values and unit symbols carefully.
TIBC may be measured or derived from transferrin depending on laboratory practice. Results from different methods may not be directly interchangeable. Review the report’s notes when trends cross laboratories.
This educational calculation does not recommend supplements, phlebotomy, or other treatment. Excess iron and unnecessary iron supplementation can be harmful; discuss unexpected results with a qualified healthcare professional.
Mass concentration units combine a mass prefix with a volume denominator. Converting g/µL therefore requires changing both the mass and volume scale; this creates a much larger factor than converting g/dL. If a source offers molar units such as µmol/L, a molar-mass conversion is required and those units are not accepted here.
Percent values above 100 can occur mathematically when serum iron exceeds reported TIBC, but such a result deserves verification of entries, units, specimen quality, and clinical context. Do not force an unexpected value into a presumed range by changing units without checking the report.
Laboratory flags may use sex, age, pregnancy, or local method information. The calculator has no access to those details. The signed laboratory report remains the correct source for its reference interval and comments.
No. TSAT is a calculated circulating iron-to-binding-capacity ratio. Ferritin is a separate laboratory marker that often helps assess iron stores and inflammation.
The page can convert supported units separately, but carefully selecting each reported unit is essential. Equivalent normalized units are used before division.
That can create a misleading ratio because serum iron varies. Use paired results from the same or clinically compatible collection whenever possible.
Use the reference interval on the specific laboratory report and the clinician’s interpretation. Ranges and decision thresholds vary with method and clinical context.
No. Low saturation has multiple possible explanations, including inflammation. Diagnosis relies on other tests, history, and clinical assessment.
Do not start or change supplementation solely from this page. Unnecessary iron can be harmful, so discuss results and treatment with a qualified professional.
Collection time, food, supplements, illness, laboratory method, and genuine health changes can affect serum iron and the calculated percentage.