Iron Sucrose Every 2 Weeks is NOT Appropriate for This Patient
Based on the patient's iron parameters (TSAT 38%, ferritin 91.63 ng/ml), intravenous iron sucrose is not indicated at this time, as the transferrin saturation exceeds the treatment threshold of 20-30% despite borderline-low ferritin. 1, 2
Analysis of Iron Parameters
Your patient's iron studies reveal:
- TSAT 38%: Above the treatment threshold of <20-30% 1, 2
- Ferritin 91.63 ng/ml: Borderline (just below the 100 ng/ml threshold) 1
- Iron 14.7 umol/l (82 mcg/dL): Within normal range
- TIBC 39.1 umol/l (218 mcg/dL): Normal
Why IV Iron is Not Indicated
The National Kidney Foundation recommends iron supplementation in CKD patients when both ferritin is <100 ng/ml and TSAT is <20% 1. Your patient meets only one criterion (low ferritin) but has adequate TSAT at 38%, indicating sufficient iron availability for erythropoiesis 1, 2.
The TSAT of 38% demonstrates that iron is adequately available to transferrin for red blood cell production, making additional IV iron unnecessary and potentially harmful. 1, 2
Treatment Thresholds for CKD Patients
Iron therapy should be initiated when: 1, 2
- TSAT ≤20-30% AND
- Ferritin <100 ng/ml
Iron therapy should be stopped when: 1, 2
- TSAT >50% OR
- Ferritin >500-800 ng/ml
Your patient's TSAT of 38% places them in the middle range where iron supplementation is not needed 1.
Special Consideration: Anemia of Chronic Disease
In anemia of chronic disease (ACD) with CKD, inflammation causes hepcidin-mediated iron sequestration, resulting in functional iron deficiency where ferritin may be normal-to-elevated despite true iron deficiency 3. However, TSAT remains the more reliable indicator of iron availability for erythropoiesis in this context 1, 2.
The KDIGO guidelines suggest considering IV iron in patients with ferritin 500-1,200 ng/ml but TSAT <25% who are below target hemoglobin or requiring high ESA doses. 1 Your patient has the opposite scenario (low ferritin, adequate TSAT), which does not warrant IV iron 1.
Appropriate Management Strategy
Monitoring Approach
- Recheck TSAT and ferritin in 3 months 1
- Monitor hemoglobin monthly 2
- Initiate iron therapy only if TSAT drops below 20-30% 1, 2
If Iron Becomes Necessary
For CKD stage 3-5 (non-dialysis): 1, 2
- First-line: Trial of oral iron 200 mg elemental iron daily for 1-3 months 1, 2
- Alternative: IV iron if oral iron fails, is not tolerated, or hemoglobin <10 g/dL 1, 2
For hemodialysis patients (if applicable): 1, 2
- IV iron is preferred and necessary 1
- Initial dosing: 100-125 mg IV per session for 8-10 consecutive sessions 1
- Maintenance: 25-125 mg IV weekly or every other week (250-1,000 mg within 12 weeks) 3
Common Pitfall to Avoid
Do not treat ferritin in isolation. Many clinicians see ferritin <100 ng/ml and reflexively order IV iron without checking TSAT 1, 2. In anemia of chronic disease, ferritin can be misleadingly low due to inflammation, but adequate TSAT (>30%) indicates sufficient iron availability 1. Unnecessary IV iron administration when TSAT is adequate increases risks of iron overload, oxidative stress, infection, and cardiovascular events 4.
Safety Concerns with Unnecessary IV Iron
Administering IV iron when not indicated carries risks: 4
- Iron overload and toxicity
- Increased infection risk
- Potential cardiovascular complications
- Oxidative stress from free iron
Iron therapy should target functional outcomes (improving hemoglobin, reducing ESA requirements, avoiding transfusions) rather than simply normalizing laboratory values. 1, 2