The Serum Iron Saturation (SIS) Calculator determines the percentage of iron bound to transferrin in your blood, a critical marker for evaluating iron metabolism. This tool helps identify iron deficiency anemia, hemochromatosis, and chronic diseases affecting iron utilization.

Formula:
(Equivalent to Transferrin Saturation (TSAT), but focuses on iron’s availability in serum.)
How to Use the Calculator
- Input Values:
- Serum Iron (lab result, in ฮผg/dL).
- TIBC (lab result, in ฮผg/dL).
Calculate SIS:
Example Calculation
- Serum Iron = 80 ฮผg/dL
- TIBC = 350 ฮผg/dL
๐งฎ Serum Iron Saturation (SIS) Calculator
๐ Formula:
SIS (%) = (Serum Iron / TIBC) ร 100
- ๐น Serum Iron: Iron in the blood (ฮผg/dL)
- ๐น TIBC: Total Iron Binding Capacity (ฮผg/dL)
Normal Range
| Group | SIS (TSAT) Range | Critical Thresholds |
|---|---|---|
| Adults | 20โ50% | <15% (Iron deficiency) >50% (Iron overload) |
Interpretation
| SIS Result | Clinical Significance |
|---|---|
| <15% | Iron deficiency anemia |
| 15โ20% | Early iron deficiency |
| 20โ50% | Normal iron metabolism |
| >50% | Hemochromatosis, iron overload, or liver disease |
Key Notes
- Units Must Match: Serum Iron and TIBC must both be in ฮผg/dL.
- Pair with Ferritin:
- Low SIS + Low Ferritin = Iron deficiency.
- Low SIS + High Ferritin = Anemia of chronic disease.
- High SIS + High Ferritin = Hemochromatosis.
- Limitations:
- Affected by inflammation, infections, or liver dysfunction.
- Not diagnostic alone; use with CBC and clinical history.
Quick Reference Table
| Condition | SIS | TIBC | Ferritin |
|---|---|---|---|
| Iron Deficiency | <15% | โโ (High) | โโ (Low) |
| Chronic Disease | 15โ20% | โ (Low) | โ/Normal |
| Hemochromatosis | >50% | โ (Low) | โโ (High) |
Calculate SIS to uncover iron disorders and guide treatment decisions!
Based on WHO and ASH guidelines.
Meta Description
“Calculate Serum Iron Saturation (SIS) to diagnose iron deficiency or overload. Learn the formula, normal ranges, and how to interpret results with ferritin and TIBC.”
Description
The Serum Iron Saturation (SIS) Calculator measures the percentage of iron bound to transferrin in your blood, critical for diagnosing iron deficiency anemia, hemochromatosis, and chronic diseases.
- Formula:
- Example: Serum Iron = 50 ฮผg/dL, TIBC = 400 ฮผg/dL โ SIS = 12.5% (Iron deficiency).
- Key Features:
- Identifies iron deficiency (SIS <15%) or overload (SIS >50%).
- Works with TIBC and ferritin for comprehensive iron studies.
- Clinical Use:
- Guides treatment for anemia, chronic kidney disease, or hereditary hemochromatosis.
- Essential for clinicians, students, and patients managing iron-related conditions.
Normal Ranges:
- SIS (TSAT): 20โ50%
- Serum Iron: 60โ170 ฮผg/dL (men), 50โ150 ฮผg/dL (women)
- TIBC: 240โ450 ฮผg/dL
Free and accurate โ analyze iron status in seconds!






