• Does this test require any preparation?

Preparation for this test requires fasting for a period of 8 to 12 hours before the blood sample is taken.

Medical Laboratories

Iron Utilization Saturation Index

Transferrin Saturation Ratio

Shows how well your body utilizes available iron for red blood cell production, essential for evaluating iron deficiency or overload.

Trusted medical contentUpdated: 04-09-2026Views: 56LHL-3220

About this service

This is a mathematical coefficient derived from two standard test results: serum iron and total iron-binding capacity (TIBC) or transferrin level. The percentage of saturation is calculated using the formula: (serum iron ÷ TIBC) × 100. This percentage represents the percentage of iron-binding sites on transferrin molecules that are actually occupied by iron, reflecting the amount of iron available to tissues (especially bone marrow) for hemoglobin production.

Conditions and notices

8-12 hours fasting

Fasting for 8-12 hours is mandatory to obtain accurate values for iron and TIBC.

It is preferable to draw the sample in the morning, as there are daily fluctuations in iron levels.

Inform your doctor about all medications and supplements you are taking, especially iron supplements or vitamins containing iron. Stop taking them at least 24-48 hours before the test, as instructed by your doctor.

Avoid consuming alcohol for 24 hours before the examination.

Acute infections or chronic diseases can affect the results, and this should be taken into account.

Frequently Asked Questions

Short answers to the FAQs published with this service.

• What does the Transferrin Saturation Ratio indicate?

It provides an indicator of the amount of "available" or "free" iron in the blood that can actually be used to produce red blood cells.

• Why is this ratio tested in long-distance runners?

It is used to evaluate athletes, particularly long-distance runners, who may experience sports-related anemia linked to iron deficiency.

• What is the importance of this test for chronic kidney disease patients?

For patients on erythropoietin (EPO), the test ensures iron levels are adequate to respond to treatment and support red blood cell production.

• What do low or high saturation levels mean?

Iron Utilization Saturation Index

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