What does a total iron level of 27 indicate and how is it treated?

Total Iron Level of 27: Interpretation and Management

A total serum iron level of 27 µg/dL is markedly low and indicates iron deficiency, requiring immediate evaluation of additional iron parameters (ferritin, transferrin saturation, hemoglobin) to confirm the diagnosis and assess severity, followed by investigation for underlying causes and initiation of iron replacement therapy. 1

Understanding the Result

What This Value Means

• Serum iron of 27 µg/dL is well below the normal range (typically 50-175 µg/dL), indicating depleted circulating iron 1
• This isolated value must be interpreted alongside other iron studies, as serum iron alone has significant limitations:
  • Exhibits substantial diurnal variation (rises in morning, falls at night) 1
  • Increases after meals 1
  • Decreases with infections and inflammation 1
  • Shows greater day-to-day variation than hemoglobin 1

Essential Confirmatory Testing

You must obtain these additional tests to establish the diagnosis: 1

• Serum ferritin (most specific test for iron deficiency):

  • <15 µg/L = highly specific for iron deficiency (99% specificity) 1
  • <30 µg/L = generally indicates low iron stores 1
  • <45 µg/L = optimal cutoff balancing sensitivity/specificity (92% specificity) 1
  • Note: Ferritin is an acute phase reactant and may be falsely normal with inflammation 1

• Transferrin saturation (calculated as serum iron/TIBC × 100):

  • <20% indicates iron deficiency 2
  • Particularly useful when ferritin may be falsely elevated by inflammation 1

• Complete blood count with indices:

  • Hemoglobin: <130 g/L (men), <120 g/L (non-pregnant women), <110 g/L (pregnant women) defines anemia 1
  • Mean cell volume (MCV): microcytosis suggests iron deficiency 1
  • Mean cell hemoglobin (MCH): more reliable than MCV for detecting iron deficiency 1

Investigating the Underlying Cause

Risk Stratification for Investigation

The urgency and extent of investigation depends on patient demographics and severity: 1

• Men and postmenopausal women: Always investigate for gastrointestinal pathology, including malignancy 1, 3
• Premenopausal women: Investigation generally not warranted if menorrhagia or recent pregnancy explains the deficiency, unless GI symptoms present 1
• Fast-track referral indicated if hemoglobin <110 g/L (men) or <100 g/L (non-menstruating women), as colorectal cancer risk is higher 1

Common Causes to Evaluate

• Bleeding sources: 2

  • Menstrual blood loss (most common in premenopausal women)
  • Gastrointestinal bleeding (peptic ulcer, inflammatory bowel disease, malignancy)
  • NSAID use

• Malabsorption: 2

  • Celiac disease
  • Atrophic gastritis
  • Post-bariatric surgery
  • Inflammatory bowel disease (13-90% prevalence of iron deficiency)

• Increased requirements/inadequate intake: 1

  • Pregnancy
  • Dietary insufficiency (vegetarian diets low in heme iron)

• Chronic inflammatory conditions: 2

  • Chronic kidney disease (24-85% prevalence)
  • Heart failure (37-61% prevalence)
  • Cancer (18-82% prevalence)

Treatment Approach

Oral Iron Therapy (First-Line for Most Patients)

Initiate oral iron supplementation while investigating the cause: 1, 2

• Dosing: Ferrous sulfate 325 mg daily or on alternate days 2

  • Alternate-day dosing may improve absorption and reduce side effects 1
  • Typical supplementation range: 100-200 mg elemental iron daily 1

• Administration tips to optimize absorption: 1

  • Take with vitamin C to enhance absorption
  • Avoid tea (tannins), dairy (calcium), and bran (phytates) at same time
  • Gradually increase dose to minimize GI side effects 4
  • Taking with meals reduces side effects but slightly decreases absorption 4

• Duration: Continue for 6 months after hemoglobin normalizes to replenish iron stores 4

• Expected response: Hemoglobin rise ≥10 g/L within 2 weeks strongly confirms iron deficiency 1

Intravenous Iron Therapy (Specific Indications)

Use IV iron in these situations: 1, 2

• Oral iron intolerance (constipation, diarrhea, nausea are common) 1
• Malabsorption conditions (celiac disease, post-bariatric surgery, inflammatory bowel disease) 2
• Chronic inflammatory conditions (CKD, heart failure, IBD, cancer) 1, 2
• Ongoing blood loss 2
• Second and third trimesters of pregnancy 2
• Need for rapid iron repletion (e.g., preoperative patient blood management) 1

IV formulations: 1

• Modern preparations (ferric carboxymaltose, ferumoxytol, isomaltoside) allow single large-dose administration
• Infusion reactions are rare (<1:250,000) but potentially life-threatening 1
• High molecular weight iron dextran carries highest risk 1

Monitoring Response

• Recheck iron studies 8-10 weeks after initiating treatment (not earlier, as ferritin falsely elevated immediately post-IV iron) 1
• Ensure underlying cause is addressed to prevent recurrence 3, 4

Critical Pitfalls to Avoid

• Do not rely on serum iron alone for diagnosis—it is too variable and must be interpreted with ferritin and transferrin saturation 1, 5
• Do not miss inflammatory conditions that falsely normalize ferritin; use transferrin saturation <20% or ferritin cutoff of 45 µg/L in these cases 1
• Do not screen men and postmenopausal women without investigating for GI pathology, as malignancy must be excluded 1, 3
• Do not assume normal CBC excludes iron deficiency—non-anemic iron deficiency is common and symptomatic 1, 5
• Do not continue oral iron indefinitely without reassessment—failure to respond warrants investigation for malabsorption or ongoing blood loss 3