GLOSSARY

Ferritin Screening in Athletes Use of ferritin testing within an appropriate athlete assessment rather than as an isolated universal performance screen.

Iron assessment distinguishes depleted stores, iron deficiency without anemia and iron-deficiency anemia. Ferritin is useful but rises with inflammation, and hemoglobin can change with plasma volume. An endurance-trained athlete may have dilutional lowering of hemoglobin without true iron depletion, yet training does not exclude genuine deficiency. Consider diet, bleeding, absorption, recent illness and exercise when interpreting tests. Confirm the problem and investigate its cause before treatment; repeated unsupervised iron use can obscure the issue and create unnecessary risk.

Anemia describes reduced blood oxygen-carrying capacity within a clinical diagnostic framework and has multiple causes. Iron deficiency, vitamin deficiencies, inflammation and blood loss require different assessments and treatment. Ferritin is influenced by inflammation, and fatigue alone does not establish iron deficiency. Do not start high-dose iron simply because an athlete reports poor performance. Evaluate the cause and relevant laboratory findings, particularly when symptoms persist, dietary intake is limited or blood loss is possible.

A recovery biomarker quantitatively relates to intake or expenditure under a specified balance model, whereas a concentration biomarker is influenced by absorption, metabolism and other factors. Predictive biomarkers use a calibrated relationship that may depend on the studied population. Distinguish intake biomarkers from markers of tissue status, function or disease. Blood, urine and tissue measurements answer different questions. Sampling conditions, recent exercise, hydration and inflammation can affect interpretation; no single biomarker provides a complete nutritional assessment or proves the cause of poor performance.