Insight into your transferrin level.

Not exactly. Transferrin is the protein itself, TIBC expresses how much iron the blood can bind in total. Because virtually all of that binding capacity comes from transferrin, the two values move together in practice and are used interchangeably. This page sells the transferrin determination; if you want TIBC and the saturation explicitly on your report, choose the Iron panel.

Transferrin saturation, also called TSAT, is the calculated ratio between the iron in your blood and the transport capacity of transferrin. You can think of transferrin as a fleet of "iron taxis"; the saturation shows which part of those taxis is occupied at that moment. For the calculation, a serum iron is needed alongside transferrin. If you order transferrin on its own, the saturation cannot be calculated; in the Iron panel it is included as standard. Saturation, iron, transferrin and ferritin are read as a set.

A low transferrin saturation can fit with iron deficiency: relatively little iron is then circulating compared with the available transport capacity, in other words many empty taxis. That is why the saturation is almost always assessed together with ferritin, which reflects the stores. Context also matters, such as the time of the blood draw and a recent illness. A single value is not a diagnosis; our doctor assesses your saturation together with your other iron values.

A high transferrin saturation can fit with a situation in which a relatively large amount of iron is circulating in the blood compared with the transport capacity. That can be temporary, for example after a meal or shortly after an iron supplement, and a repeat measurement can then already clarify a lot. If the value remains high, our doctor explains whether investigation into iron overload is customary, including the hereditary form (haemochromatosis). A high saturation on its own is not a diagnosis.

Ferritin reflects the iron stores in your body and is usually the most important marker for questions about iron deficiency. Transferrin is about transport and often moves in the opposite direction from the stores. Together they give a fuller picture than either does alone.

Fasting is not strictly required. If transferrin is determined together with serum iron, a draw in the morning before breakfast is advisable, because serum iron fluctuates over the day and rises after a meal or supplement.

Yes. Oestrogen-containing medication and pregnancy generally go together with a higher transferrin. That is a known effect and not an abnormality in itself. Mention it during your intake, so our doctor assesses your result in that context.

Yes. During inflammation the liver produces less transferrin, while ferritin rises instead. That is exactly why the two values add so much alongside each other, and why an inflammation marker such as CRP often gives useful context.

A single measurement is enough for initial insight, preferably together with ferritin and iron. If you take supplements or an earlier value was abnormal, re-testing after a few months is customary. Our doctor advises on this.

You receive a PDF report with your value and a personal explanation from a doctor. What you do with it, such as discussing it with your GP, remains entirely your choice.