Immediately Stop Iron Supplementation
The next step is to discontinue iron supplementation immediately due to dangerously high iron saturation (79%) indicating iron overload risk. 1
Critical Laboratory Interpretation
Your patient presents with a paradoxical iron profile that signals functional iron overload despite low ferritin:
- Iron saturation 79%: This is critically elevated and exceeds the safety threshold of 50% 1
- Ferritin 28 ng/mL: Indicates depleted iron stores 2
- Total iron binding capacity 360: Within normal range
- Serum iron 285: Elevated relative to binding capacity
Immediate Management Algorithm
Step 1: Stop All Iron Supplementation (Oral and IV)
- Withhold iron therapy immediately when transferrin saturation exceeds 50%, regardless of ferritin levels 1
- The KDOQI guidelines explicitly state there is no physiologic rationale for maintaining TSAT >50% and patients with transfusional hemosiderosis have TSAT ≥80% 1
- Your patient's TSAT of 79% approaches the threshold seen in iron overload states 1
Step 2: Repeat Iron Studies in 2-4 Weeks
- Recheck ferritin, TSAT, serum iron, and TIBC after stopping iron 1, 2
- Assessment of iron parameters after iron administration may require an interval of 7 or more days for accurate interpretation 1
- Monitor for resolution of elevated TSAT while tracking ferritin trends 2
Step 3: Investigate Underlying Cause of Discordant Iron Parameters
Evaluate for conditions causing high TSAT with low ferritin:
- Hemochromatosis or iron-loading disorders: High iron saturation is the hallmark early finding, often preceding ferritin elevation 3
- Chronic kidney disease: Assess renal function as CKD patients have altered iron metabolism 1
- Inflammatory conditions: Check C-reactive protein (CRP) to determine if ferritin is falsely low due to lack of acute phase response 4, 5
- Ongoing blood loss: Low ferritin with high TSAT may indicate chronic bleeding with recent iron supplementation 3
Step 4: Resume Iron Only When Safe
Do not restart iron supplementation until:
- TSAT falls below 50% 1
- Ferritin remains <100 ng/mL AND TSAT <20% (if truly iron deficient) 1
- Underlying cause of discordant parameters is identified 2
Critical Safety Considerations
Common pitfalls to avoid:
- Never continue iron based solely on low ferritin when TSAT is elevated—this risks iron toxicity 1
- Do not assume low ferritin always means iron deficiency—ferritin can be low in hemochromatosis patients who have been over-phlebotomized or in those with genetic iron-loading disorders 3
- Avoid treating numbers without clinical context—assess for symptoms of iron overload (fatigue, joint pain, liver dysfunction) versus iron deficiency (anemia symptoms) 3
Monitoring During Iron Withdrawal Period
- Recheck complete blood count to assess for anemia development 2, 3
- Monitor TSAT and ferritin every 2-4 weeks initially, then every 3 months once stable 1
- If anemia develops during withdrawal, this suggests true iron deficiency and iron can be cautiously reintroduced at lower doses once TSAT normalizes 3
The guideline threshold is clear: IV iron should be withheld when TSAT >50% and can be resumed only when TSAT falls to ≤50%, typically at a dose reduced by one-third to one-half of the previous regimen 1