Ferritin

What Ferritin Measures

Ferritin is the body's main iron-storage protein, holding iron in a form cells can draw on later.^[1] Only a small fraction of the body's ferritin circulates in blood, but absent inflammation that circulating amount correlates with the much larger pool held in storage.^[2] That's why a ferritin blood test works as an indicator of total body iron rather than a direct count of stored iron itself.

How It's Measured

Ferritin is measured from a standard venous blood draw and reported in nanograms per milliliter. It's typically ordered as part of an iron panel alongside serum iron, total iron-binding capacity (TIBC), and transferrin saturation, since each of those tests reflects a different part of how iron moves through and is held in the body.^[4] Labs set and report their own reference interval with each result, and that interval can vary by lab and by testing method.

Why People Track Ferritin

Menstrual blood loss is one of the measurable, population-level factors linked to iron stores in people who menstruate. In a 2024 study of 473 premenopausal blood donors, menstrual blood loss was an independent predictor of both hemoglobin and ferritin levels, alongside factors like time since a person's last blood donation.^[3] That's the mechanism that puts a lab value like ferritin within reach of a menstrual-health tracker: it's a number tied to a bodily process, blood loss, that a period tracker already logs on its own.

How Go Go Gaia Tracks Ferritin

Go Go Gaia doesn't draw blood or run lab work. You can upload a ferritin result from a lab draw you've already had done, and the app adds it to your account as a dated data point alongside your other health data. From there, it's charted on your timeline next to your logged period flow and cycle days, so you can see where a ferritin draw fell relative to your cycle instead of looking at the number in isolation.

What the Research Shows

Ferritin's role as the body's primary iron-storage protein has been established for decades, and it remains the basis for using it as a lab marker of iron status.^[1]

A 2020 WHO guideline on assessing iron status confirms the correlation above: absent inflammation, ferritin concentration tracks the size of the body's total iron stores.^[2]

Menstrual blood loss showed up as an independent, measurable determinant of ferritin and hemoglobin levels in a cohort of 473 premenopausal blood donors, on par with other established determinants of iron status.^[3]

Related Terms

Frequently Asked Questions

Educational information based on published sources. Not medical advice. For personal concerns, please consult your doctor.

Does Go Go Gaia run ferritin blood tests?

No. Go Go Gaia doesn't draw blood or run labs. You get a ferritin result from a blood draw ordered through a clinician or lab service, then upload it to your Go Go Gaia account so it's stored alongside your other tracked data.

What's the difference between ferritin and iron on a lab panel?

Serum iron measures the iron actively circulating in blood at the moment of the draw, while ferritin reflects iron held in storage inside cells. Total iron-binding capacity (TIBC) and transferrin saturation describe how much of the blood's iron-carrying capacity is in use. The four are typically ordered and read together as an iron panel.

Why would a period tracker include a lab value like ferritin?

Menstrual blood loss is one of the measurable, population-level factors tied to iron stores in people who menstruate. A ferritin result fits naturally next to logged period-flow data because both are part of the same picture of iron balance over time.