Transferrin

What it is

Transferrin is a protein made in your liver. Its main job is to carry iron around your body in your bloodstream. Iron is a vital mineral that your body needs for many functions, including making red blood cells, which carry oxygen to all your tissues. Transferrin binds to iron and delivers it to where it's needed, such as your bone marrow for making new red blood cells, or to your liver for storage.

Think of transferrin as a delivery truck for iron. It picks up iron from the places where it's absorbed (mainly in your gut) or released from old red blood cells, and transports it to the cells that need it.

Why it matters

The level of transferrin in your blood can give doctors clues about how your body is handling iron. If your iron levels are low, your body might make more transferrin to try and capture as much iron as possible from your diet. Conversely, if you have too much iron, your body might produce less transferrin.

Measuring transferrin, often alongside other iron-related tests like ferritin and iron levels, helps paint a picture of your iron status. This can be important for understanding conditions related to too little iron (like iron deficiency anaemia) or too much iron (like haemochromatosis).

The typical reference range for transferrin in the UK is generally between 2 and 3.8 grams per litre (g/l). However, it's important to remember that laboratory reference ranges can vary slightly, and what's considered normal can depend on factors like your age and sex.

What can cause it to be high or low

Higher than normal transferrin levels can be associated with:

• Iron deficiency: This is the most common reason for high transferrin. When your body doesn't have enough iron, your liver produces more transferrin to try and maximise iron absorption and transport.
• Pregnancy: Transferrin levels naturally rise during pregnancy to meet the increased iron demands of both the mother and the developing baby.
• Liver disease: In some types of liver disease, the liver may produce more transferrin.
• Anaemia not caused by iron deficiency: Certain other types of anaemia, where red blood cells are not being produced effectively, can sometimes lead to higher transferrin levels.

Lower than normal transferrin levels can be associated with:

• Iron overload: Conditions where the body absorbs or stores too much iron, such as hereditary haemochromatosis, can lead to lower transferrin levels as the body tries to reduce iron uptake.
• Liver disease: Severe liver damage can impair the liver's ability to produce transferrin.
• Malnutrition or protein deficiency: Since transferrin is a protein, a lack of protein in the diet can lead to lower levels.
• Inflammation or infection: During periods of significant inflammation or infection, transferrin levels can sometimes decrease. This is because the body may divert resources away from producing transferrin and towards other immune functions.

Lifestyle factors that may help

While your transferrin level is primarily influenced by your body's iron status and overall health, certain lifestyle choices can support healthy iron metabolism. Discussing these with your GP is a good idea.

• Dietary iron intake: Ensuring a balanced diet that includes good sources of iron, such as lean red meat, poultry, fish, beans, lentils, and fortified cereals, is fundamental. For those who don't eat meat, including plenty of plant-based iron sources alongside vitamin C-rich foods (which help iron absorption) can be beneficial.
• Alcohol consumption: Excessive alcohol intake can affect liver function, and the liver is responsible for producing transferrin. Moderating alcohol consumption may be helpful for liver health.
• Balanced diet: A generally healthy and balanced diet supports overall bodily functions, including the production of proteins like transferrin.

Questions to discuss with your GP

If your transferrin results are outside the normal range, or if you have concerns about your iron levels, it's always best to have a conversation with your GP. Here are some questions you might consider discussing:

• What do my transferrin results mean in the context of my overall health and any other test results?
• Could my transferrin level indicate an iron deficiency or iron overload?
• Are there any further tests you would recommend to investigate my iron status?
• What dietary changes might be most beneficial for me, given my results?
• Are there any lifestyle factors I should be particularly mindful of?
• How often should my iron status be monitored?