Transferrin Blood Test: Normal Ranges, Causes & What Your Results Mean

What Is Transferrin?

Transferrin is a glycoprotein produced by the liver that serves as the primary iron transport vehicle in the blood. Each transferrin molecule can bind two iron atoms, carrying iron from the gut (after dietary absorption), from storage sites (liver, spleen), and from recycled red blood cells to the bone marrow for new haemoglobin synthesis.

Transferrin levels are regulated inversely to iron status: when iron stores are low, the liver produces more transferrin to scavenge available iron more efficiently. When iron is plentiful, transferrin production decreases. This makes transferrin a useful indirect marker of iron status, complementing ferritin, serum iron, and TIBC.

Why Is Transferrin Tested?

• Iron deficiency assessment — elevated transferrin confirms the body is trying to capture more iron
• Differentiating types of anaemia — iron-deficiency anaemia (high transferrin) vs anaemia of chronic disease (low transferrin)
• Iron overload investigation — low transferrin with high iron and transferrin saturation suggests haemochromatosis
• Nutritional status — transferrin is a negative acute-phase reactant and marker of protein nutrition
• Calculating transferrin saturation — TSAT% = (serum iron ÷ TIBC or transferrin-derived capacity) × 100

Normal Ranges

What Do High Transferrin Levels Mean?

• Iron deficiency — the liver upregulates transferrin to maximise iron capture
• Pregnancy — increased iron demands stimulate transferrin production
• Oral contraceptives — oestrogen stimulates hepatic protein synthesis

What Do Low Transferrin Levels Mean?

• Inflammation/chronic disease — transferrin is a negative acute-phase reactant; it falls during infection, inflammation, and malignancy
• Iron overload — haemochromatosis reduces transferrin production
• Liver disease — impaired hepatic synthesis
• Nephrotic syndrome — urinary protein loss includes transferrin
• Malnutrition — severe protein-calorie malnutrition reduces all liver proteins

How to Interpret Your Results

• High transferrin + low iron + low ferritin = iron deficiency
• Low transferrin + low iron + normal/high ferritin = anaemia of chronic disease
• Low transferrin + high iron + high ferritin + high TSAT = iron overload
• Always interpret as part of the full iron panel — no single marker gives the complete picture

When Should You Get Tested?

• As part of a comprehensive iron panel for anaemia investigation
• Monitoring iron supplementation therapy
• Suspected iron overload or haemochromatosis
• Persistent fatigue with borderline iron results

Which Lola Health Tests Include Transferrin?

Transferrin is included in the iron panel alongside serum iron, ferritin, and TIBC in Vital Check and Peak Insights. Available as an add-on with any blood test.