WHO Recommendations

Ferritin concentration is a good marker of iron stores and should be used to diagnose iron deficiency in otherwise apparently healthy individuals.

In individuals with infection or inflammation, a ferritin concentration below 30 µg/L in children and 70 µg/L in adults may be used to indicate iron deficiency (conditional recommendation,5 low certainty of evidence). In populations it is also possible to adjust ferritin values for infection/inflammation by applying correction factors.

A ferritin concentration exceeding 150 µg/L in menstruating women and 200 µg/L in men and non-menstruating women who are otherwise healthy may indicate a risk of iron overload (conditional recommendation, based on previous WHO recommendation). In adult, non-healthy individuals, a ferritin concentration exceeding 500 µg/L may indicate risk of iron overload.

Ferritin concentration should not be used alone to identify risk of iron overload. Patients with elevated ferritin levels should receive clinical and laboratory evaluation to establish the underlying cause.

Ferritin concentration increases in response to iron-related interventions and may be used to monitor and assess the impact of interventions on iron status.

Ferritin may be measured using radiometric, nonradiometric and agglutination assays. One method does not appear to be superior to another and all methods are acceptable if a commutable material traceable to the WHO international reference standard is used to calibrate the assay. Once a method has been selected, that same method should be used for the follow-up of individuals and populations.

Use of the WHO international reference standard of ferritin is recommended for calibration of all commercial kits and in regular laboratory practice, especially when following up individual cases, for population surveys or to measure the impact of public health interventions.

In areas of widespread infection or inflammation, serum ferritin should be assessed with the concurrent measurement of two acute phase response proteins, CRP and AGP.

The increase in ferritin values caused by inflammation should be accounted for in individuals and populations. One method is to raise the cut-off value that defines deficiency, to 30 µg/L or 70 µg/L, depending on the age group. Another method is to exclude individuals with elevated concentrations of CRP or AGP from prevalence calculations based on ferritin. Alternatively, arithmetic or regression correction approaches may be used to adjust ferritin concentrations for inflammation and apply the cut-off points recommended for healthy populations. The adjustment that best suits the country reality should be selected and used as long as those conditions prevail.