Iron deficiency

Biomarkers

Start with the primary markers, then add the companions that change how the primary result reads. Each link cites its source.

• FerritinPrimary marker

  AGA recommends a ferritin cut-off of 45 ng/mL over 15 ng/mL to diagnose iron deficiency.

  Tests: Labcorp 12, Quest Diagnostics 3, with ranges on the biomarker page

  AGA Clinical Practice Guidelines on the Gastrointestinal Evaluation of Iron Deficiency Anemia, American Gastroenterological Association, 2020

• IronCompanion marker

  MedlinePlus lists the serum iron test among the iron tests used to check for low iron.

  Tests: Labcorp 7, Quest Diagnostics 5, with ranges on the biomarker page

  Iron Tests, MedlinePlus, US National Library of Medicine, 2026

• Iron Binding CapacityCompanion marker

  MedlinePlus lists total iron-binding capacity (TIBC) among the iron tests used to check for low iron.

  Tests: Labcorp 6, Quest Diagnostics 2

  Iron Tests, MedlinePlus, US National Library of Medicine, 2026

Related

• Iron deficiency anemia
• Anemia
• Hereditary hemochromatosis
• Energy and fatigue

Sources

• AGA Clinical Practice Guidelines on the Gastrointestinal Evaluation of Iron Deficiency Anemia, American Gastroenterological Association, 2020

  Clinical guideline

• Iron Tests, MedlinePlus, US National Library of Medicine, 2026

  Government source