Iron Panel Workup: When to Test
Screen all adults with anemia (hemoglobin <13 g/dL in men, <12 g/dL in non-pregnant women) and obtain iron studies including serum ferritin and transferrin saturation. 1, 2
Mandatory Screening Populations
Universal Screening Recommended
- All adults with anemia regardless of symptoms should undergo iron panel testing 1, 2
- All pregnant women at first prenatal visit 1
- All adults with hereditary hemorrhagic telangiectasia (HHT) regardless of bleeding symptoms 1
- All newly diagnosed heart failure patients (LVEF ≤45%) as part of initial diagnostic workup 1
- All patients with chronic kidney disease when GFR <30 mL/min/1.73 m² 1
Symptom-Based Testing
Obtain iron studies in patients presenting with: 2
- Fatigue or exercise intolerance
- Restless legs syndrome (present in 32-40% of iron deficiency cases)
- Pica (present in 40-50% of iron deficiency cases)
- Difficulty concentrating, irritability, or depression
- Dyspnea or lightheadedness
- Hair loss
High-Risk Populations Requiring Screening
Test iron studies every 3 months in: 1
- Inflammatory bowel disease patients (13-90% prevalence of iron deficiency)
- Chronic heart failure patients (37-61% prevalence) 1
- Chronic kidney disease patients (24-85% prevalence) 2
- Cancer patients (18-82% prevalence) 1, 2
Test annually or when symptomatic: 1
- Women of reproductive age with heavy menstrual bleeding (38% have iron deficiency without anemia, 13% have iron-deficiency anemia) 2
- Patients post-bariatric surgery 2
- Patients with celiac disease 1
- Patients with atrophic gastritis 2
Children
- All children at 1 year of age 1, 3
- Children with HHT who have recurrent bleeding and/or symptoms of anemia 1
- High-risk infants (6-12 months) from low-income families or living at/below poverty level 1
What to Order
Essential iron panel components: 1, 2
- Serum ferritin (most important single test)
- Transferrin saturation (TSAT = serum iron/total iron-binding capacity × 100)
- Complete blood count with hemoglobin
Additional tests when ferritin is equivocal (45-100 ng/mL): 1, 2
- Soluble transferrin receptor
- Reticulocyte hemoglobin equivalent
- C-reactive protein (to assess for inflammation)
Diagnostic Thresholds
Iron deficiency is diagnosed when: 1, 2
- Ferritin <45 ng/mL (in absence of inflammation), OR
- Ferritin <100 ng/mL with TSAT <20% (in inflammatory conditions)
For heart failure patients specifically: 1
- Ferritin <100 μg/L (absolute deficiency), OR
- Ferritin 100-299 μg/L with TSAT <20% (functional deficiency)
When NOT to Screen
Do not perform routine screening in: 1, 3
- Asymptomatic adult men without risk factors
- Asymptomatic postmenopausal women without risk factors
- Full-term infants <6 months of age with normal birthweight 1
Monitoring After Treatment
Recheck iron studies: 1
- 8-10 weeks after oral iron initiation (not earlier, as ferritin falsely elevated after IV iron for 4 weeks) 1
- Every 3 months for at least 1 year after correction in IBD patients 1
- 1-2 times per year in chronic heart failure patients as routine follow-up 1
- Every 3 months in chronic kidney disease patients with GFR <30 mL/min/1.73 m² 1
Critical Pitfalls to Avoid
- Do not rely on ferritin alone in inflammatory conditions (chronic kidney disease, heart failure, IBD, cancer, infection) as it is an acute phase reactant and may be falsely elevated 1, 2
- Do not recheck iron studies within 4 weeks of IV iron administration as ferritin levels are artificially elevated and unreliable during this period 1
- Do not skip iron studies before starting erythropoiesis-stimulating agents as many insurers require documentation and iron deficiency blunts ESA response 1
- Do not assume normal ferritin excludes iron deficiency in inflammatory states—use TSAT <20% as confirmatory test when ferritin is 45-100 ng/mL 1, 2