Can You Stop Iron Therapy with Ferritin 120 and TSAT 21?
No, you should not stop iron therapy with a ferritin of 120 ng/mL and TSAT of 21%, as the TSAT remains just above the minimum threshold and many patients with these values still have functional iron deficiency requiring continued supplementation.
Clinical Context and Decision Framework
Your iron parameters place you in a borderline zone where the decision depends critically on your clinical context:
Key Thresholds to Understand
- Minimum targets: TSAT ≥20% AND ferritin ≥100 ng/mL are the baseline thresholds that should be maintained in all CKD patients 1
- Your current status: Ferritin 120 ng/mL (adequate) but TSAT 21% (barely adequate)
- Upper safety limits: TSAT <50% and ferritin <800 ng/mL 1
Why You Should Continue Iron Therapy
Many patients remain functionally iron deficient even when TSAT is ≥20% and ferritin is ≥100 ng/mL 1. The guidelines explicitly state that additional iron should be given to patients whose parameters are at these threshold levels, particularly when:
- Hemoglobin/hematocrit remains <33% 1
- Erythropoietin (Epoetin) doses are higher than anticipated 1
- The goal is to optimize erythropoiesis, not simply achieve specific lab values 1
Clinical Algorithm for Your Situation
If you are on hemodialysis:
- Continue maintenance IV iron at 25-125 mg weekly to maintain TSAT >20% and ferritin >100 ng/mL 1
- Your TSAT of 21% provides minimal buffer above the 20% threshold 1
- Monitor iron parameters every 3 months 1
If your hemoglobin is suboptimal (<11 g/dL) or you require high Epoetin doses:
- Consider a trial of 1.0 g IV iron over 8-10 weeks to assess response 1
- Observe for increased hemoglobin or decreased Epoetin requirement 1
- This approach is reasonable even with your current parameters 1
If your hemoglobin is at target (11-12 g/dL) and stable:
- Continue reduced maintenance iron dosing rather than stopping completely 1
- The goal is preventing decline, as most hemodialysis patients cannot maintain adequate iron status without ongoing supplementation 1
Important Caveats
The TSAT is More Critical Than Ferritin
Recent evidence suggests that TSAT <20% (hypoferremia) is the most reliable marker of true iron deficiency and predicts response to iron therapy 2. Your TSAT of 21% is only marginally above this threshold, leaving little margin for error.
Ferritin Can Be Misleading
- Ferritin is an acute-phase reactant that increases with inflammation 1, 3
- In inflammatory conditions (common in CKD), ferritin may be elevated despite true iron deficiency 3, 4
- A ferritin of 120 ng/mL does not guarantee adequate iron availability for erythropoiesis 1, 3
Risk of Stopping Prematurely
If you stop iron now, you risk:
- TSAT falling below 20% due to ongoing blood losses (especially in hemodialysis) 1
- Development of functional iron deficiency despite adequate ferritin 1
- Increased Epoetin requirements or declining hemoglobin 1
When to Actually Stop or Hold Iron
Only consider stopping iron if:
- TSAT rises to ≥50% OR ferritin rises to ≥800 ng/mL 1
- In this case, withhold IV iron for up to 3 months, then recheck parameters 1
- Resume at reduced dose (one-third to one-half previous dose) when levels normalize 1
Practical Recommendation
Continue iron supplementation at a maintenance dose appropriate for your clinical setting (hemodialysis vs. peritoneal dialysis vs. non-dialysis CKD) 1. Your current parameters are at the minimum acceptable threshold, not at a level that indicates iron repletion sufficient to discontinue therapy. The evidence consistently shows that most CKD patients, particularly those on hemodialysis, require ongoing iron supplementation to maintain adequate iron status and optimal hemoglobin levels 1.