What do the following lab results indicate: Hemoglobin (Hgb) 129 g/l, Hematocrit (Hct) 0.40, Mean Corpuscular Volume (MCV) 92 fl, Iron serum level 27, Iron saturation level 0.54 umol/L, Ferritin level 41 ug/l, and Transferrin level 2.00 g/l?

Laboratory Interpretation: Borderline Iron Deficiency

These laboratory results indicate borderline iron deficiency without anemia, requiring iron supplementation and investigation for underlying causes, particularly gastrointestinal blood loss.

Hemoglobin and Anemia Assessment

• Hemoglobin 129 g/L is at the lower limit of normal for males (WHO threshold <130 g/L) but within normal range for non-pregnant females (WHO threshold <120 g/L), meaning this patient is technically not anemic if female, but borderline if male 1
• Hematocrit 0.40 (40%) is normal and consistent with the hemoglobin level 1
• MCV 92 fL is normocytic, indicating red blood cells are normal size, which can occur in early iron deficiency before microcytosis develops 1

Iron Status Interpretation

• Ferritin 41 μg/L indicates depleted iron stores 1, 2

  • This level falls between the <35 μg/L threshold for iron deficiency in athletes 1 and the <45 μg/L threshold that provides 92% specificity for iron deficiency in general populations 2
  • While not severely depleted, this ferritin level warrants treatment and investigation 1

• Transferrin 2.00 g/L is at the upper limit of normal (normal range typically 2.0-3.6 g/L), which is consistent with iron deficiency as transferrin increases when iron stores are depleted 2

• Iron saturation 0.54 μmol/L appears to be reported in unusual units; if this represents transferrin saturation as a percentage, it would be extremely low and confirm iron deficiency (normal >20%) 1, 2

Clinical Significance

This patient has iron deficiency without overt anemia, representing an early stage where iron stores are depleted but hemoglobin production is still maintained 1:

• Even without anemia, iron deficiency can cause lethargy, reduced performance, and impaired oxidative metabolism 1
• The normocytic MCV does not exclude iron deficiency, as microcytosis is a late finding that only develops after prolonged iron depletion 1, 3
• Normal hemoglobin and hematocrit can be misleading and do not rule out clinically significant iron deficiency 3

Recommended Actions

Immediate steps:

• Initiate iron supplementation with oral iron preparations, as ferritin <45 μg/L warrants treatment 1, 2
• Co-administer vitamin C with iron to enhance absorption 1
• Avoid tea and coffee around meal times as they impair iron absorption 1

Investigation for underlying cause:

• In males or postmenopausal females, iron deficiency at any level requires gastrointestinal investigation to exclude bleeding lesions, as approximately 62% have identifiable GI pathology 2
• Test for celiac disease with tissue transglutaminase antibodies, as this is a common cause of iron deficiency 2
• Test for H. pylori infection before proceeding to endoscopy 2
• Consider bidirectional endoscopy (upper and lower) for men and postmenopausal women 2

Monitoring:

• Recheck iron parameters (ferritin, transferrin saturation) and hemoglobin 4-8 weeks after starting supplementation 2
• Hemoglobin should increase by 1-2 g/dL within 4-8 weeks if treatment is effective 2
• A hemoglobin rise ≥10 g/L within 2 weeks strongly confirms iron deficiency even if initial iron studies were equivocal 1

Critical Pitfalls to Avoid

• Do not dismiss this as normal based on hemoglobin alone—iron deficiency exists before anemia develops and requires treatment 1, 3
• Do not assume dietary insufficiency without investigation—in men and postmenopausal women, GI bleeding is the most common cause 2
• Do not rely on MCV to exclude iron deficiency—microcytosis is a late finding and normal MCV does not rule out iron depletion 1, 3
• If inflammation or chronic disease is present, ferritin may be falsely elevated, so consider using a higher threshold (<100 μg/L) in those contexts 1, 2