What tests and assessments are required before initiating iron chelation therapy?

Protocol and Tests Before Starting Iron Chelation Therapy

Before initiating iron chelation therapy, comprehensive baseline assessments of iron overload status, organ function, and potential contraindications must be performed to ensure safe and effective treatment.

Initial Assessment of Iron Overload

• Serum ferritin measurement: Must be consistently >1,000 ng/mL 1, 2
• Transfusion history documentation:
  • Verify receipt of approximately 20 units of packed red blood cells 2
  • Confirm transfusion dependency (≥2 units/month for >1 year) 1, 2
• Iron store assessment: Should be performed at diagnosis and regularly thereafter 1

Required Baseline Laboratory Tests

• Renal function assessment 3:

  • Serum creatinine in duplicate
  • Estimated glomerular filtration rate (eGFR)
  • Urinalysis and serum electrolytes to evaluate tubular function
  • Contraindicated in adults with eGFR <40 mL/minute/1.73 m²

• Hepatic function evaluation 3:

  • Serum transaminases
  • Bilirubin
  • Assessment of hepatic impairment (Child-Pugh score)

• Hematologic parameters:

  • Complete blood count with differential
  • Platelet count (especially important due to risk of GI hemorrhage) 3

Organ Function Assessment

• Cardiac evaluation:

  • Cardiac MRI with T2* measurement when available 1, 2
  • Baseline ECG and echocardiogram
  • Significant cardiac abnormalities have been demonstrated with transfusions exceeding 100 units 1

• Hepatic iron assessment:

  • Liver MRI for iron quantification 1, 2
  • Consider SQUID (superconducting quantum interference device) if available 1
  • Liver biopsy is gold standard but invasive and generally not required if MRI is available 4

• Baseline sensory function:

  • Auditory examination 3
  • Ophthalmic examination 3

Additional Considerations

• Rule out other causes of elevated ferritin 2:

  • Inflammatory conditions
  • Chronic alcohol consumption
  • Malignancies (particularly lymphomas)
  • Non-alcoholic fatty liver disease
  • Metabolic syndrome

• Genetic testing:

  • Consider HFE mutation testing to rule out hereditary hemochromatosis in appropriate patients 2

Monitoring Protocol During Therapy

• Serum ferritin: Every 3 months (monthly if possible) 1
• Renal function: At least monthly; weekly for first month in high-risk patients 3
• Hepatic function: Every 2 weeks during first month, then monthly 3
• Complete blood count: Regular monitoring, especially with deferiprone due to risk of agranulocytosis 5

Pitfalls to Avoid

• Initiating therapy without confirming true iron overload (vs. inflammatory causes of hyperferritinemia) 2
• Starting chelation during ongoing immunosuppressive therapy due to overlapping renal toxicity 1
• Using excessive dosages that may result in growth retardation, sensorineural ototoxicity, ocular toxicity, or bone deformities 6
• Failing to adjust dosage based on the degree of iron overload 6
• Overlooking the need for more frequent monitoring in pediatric patients with acute illnesses causing volume depletion 3

Iron chelation therapy should be tailored based on the results of these assessments, with careful consideration of the patient's specific condition, transfusion requirements, and risk factors for adverse effects.