Iron Deficiency Treatment with Ferritin 25 ng/mL and Prior IV Iron History
This patient requires intravenous iron supplementation given the ferritin level of 25 ng/mL, which is well below treatment thresholds across all clinical contexts. 1
Diagnostic Confirmation and Context Assessment
Ferritin 25 ng/mL confirms absolute iron deficiency regardless of the clinical setting (CKD, IBD, general population, or cancer-related anemia). 1, 2, 3
Check transferrin saturation (TSAT) if not already done—values <20% further confirm iron deficiency and guide treatment intensity. 1, 2
Assess hemoglobin level to determine urgency and whether erythropoiesis-stimulating agents (ESAs) are needed if this is CKD-related anemia. 1
Rule out active inflammation by checking C-reactive protein, as ferritin can be falsely elevated in inflammatory states (though 25 ng/mL is definitively low regardless). 4, 2
Treatment Approach Based on Clinical Context
For CKD Patients (Most Likely Given IV Iron History)
Intravenous iron is strongly preferred and likely necessary:
Target ferritin ≥100 ng/mL and TSAT ≥20% to optimize erythropoiesis and reduce ESA requirements. 1
Administer 100-125 mg IV iron per dialysis session for 8-10 consecutive sessions if the patient is on hemodialysis. 1
For non-dialysis CKD or peritoneal dialysis patients, give 500-1,000 mg iron dextran as a single IV infusion (after 25 mg test dose) or use iron sucrose/ferric gluconate in divided doses. 1, 5, 6
Oral iron is ineffective in most hemodialysis patients and unlikely to maintain adequate iron stores even in non-dialysis CKD patients. 1
For IBD Patients
Intravenous iron is the preferred route:
Use IV iron for ferritin <100 μg/L to prevent rapid recurrence of deficiency. 1
Calculate total iron dose based on hemoglobin and body weight: 1,000-1,500 mg for body weight <70 kg with Hb 10-12 g/dL (women) or 10-13 g/dL (men). 1
Oral iron may be considered only if disease is clinically inactive, anemia is mild (Hb 11.0-11.9 g/dL in women, 11.0-12.9 g/dL in men), and patient has not previously been intolerant—but IV iron remains superior. 1
For General Population Without CKD or IBD
Oral iron is first-line unless contraindications exist:
Ferrous sulfate 325 mg daily or every other day (every-other-day dosing improves absorption and reduces side effects). 2, 3
Switch to IV iron if: oral iron intolerance occurs (~50% of patients), malabsorption is present (celiac disease, post-bariatric surgery), ongoing blood loss continues, or patient is in second/third trimester of pregnancy. 2, 3
For symptomatic patients with fatigue, restless legs, or pica, treatment is indicated even with ferritin 25 ng/mL. 4, 3
IV Iron Formulation Selection
Given prior IV iron history, determine which formulation was used and whether adverse reactions occurred:
Iron sucrose (Venofer): 100-200 mg per dose, can be given over 10-60 minutes, lower anaphylaxis risk. 5, 6
Ferric gluconate (Ferrlecit): 62.5-125 mg per dose, requires slower infusion (1 hour), test dose recommended. 5
Ferric carboxymaltose (Ferinject): up to 1,000 mg single dose over 15 minutes, no test dose required, most convenient but higher cost. 1
Iron dextran (Cosmofer): allows total dose infusion (500-1,000 mg), but highest anaphylaxis risk (0.6-0.7%), requires 25 mg test dose. 1
If prior iron dextran intolerance occurred, use iron sucrose or ferric gluconate as alternatives with lower hypersensitivity rates. 5, 6
Monitoring and Maintenance
Recheck ferritin and TSAT 2-4 weeks after completing initial IV iron course (allow 7+ days after last dose for accurate assessment). 1
For CKD patients, monitor iron parameters every 3 months and provide maintenance IV iron (25-125 mg weekly) to keep ferritin ≥100 ng/mL and TSAT ≥20%. 1
For IBD patients, monitor every 3 months for the first year, then every 6-12 months; re-treat when ferritin drops below 100 μg/L. 1
For general population on oral iron, reassess in 8-10 weeks; if ferritin remains low despite adherence, switch to IV iron. 4, 2
Upper safety limits: withhold IV iron if ferritin >800 ng/mL or TSAT >50% to avoid potential iron overload. 1
Critical Safety Considerations
Have resuscitation equipment and medications (epinephrine, diphenhydramine, corticosteroids) immediately available during IV iron administration for rare anaphylaxis-like reactions (<1% incidence). 1
Hypersensitivity risk is highest with iron dextran; newer formulations (iron sucrose, ferric carboxymaltose) have lower rates. 1, 5, 6
In pregnancy, IV iron is preferred in second/third trimesters when oral iron is insufficient, but hypersensitivity reactions may have serious fetal consequences. 5, 3
Long-term high-dose IV iron safety remains uncertain—avoid maintaining ferritin chronically >500-800 ng/mL without clear indication. 1, 7