Private Carbohydrate Deficient Transferrin (CDT) (Venous) Test in the City of London

Iron is an essential mineral that the body needs to produce haemoglobin, the protein in red blood cells that carries oxygen throughout the body. Without adequate iron, the body cannot produce enough healthy red blood cells, which can lead to iron deficiency anaemia.

Iron deficiency is one of the most common nutritional deficiencies worldwide. In the UK, it is particularly prevalent among women of reproductive age, pregnant women, vegetarians, and individuals with chronic health conditions.

What the Carbohydrate Deficient Transferrin (CDT) (Venous) Measures

• Serum iron — the amount of iron circulating in the blood
• Ferritin — a protein that stores iron; low ferritin indicates depleted iron reserves
• Transferrin / TIBC — proteins that transport iron; elevated levels may indicate iron deficiency
• Transferrin saturation — the percentage of transferrin bound to iron

When This Test May Be Helpful

• Persistent fatigue, weakness, or low energy
• Pale skin, brittle nails, or hair thinning
• Shortness of breath during normal activities
• Heavy menstrual periods
• A vegetarian or vegan diet
• Monitoring iron supplementation
• Unexplained dizziness or headaches

Understanding Your Results

Results are typically available within 3 days" and are delivered securely.

Your results will show whether your iron levels and stores are within the expected range. Low ferritin is often the earliest indicator of iron depletion, even before anaemia develops.

Both low and high iron levels can be clinically significant. If your results are outside the normal range, we recommend sharing them with your GP, who can provide advice on diet, supplementation, or further investigation as needed.