What is a prealbumin blood test?

A prealbumin blood test measures prealbumin levels in your blood. Prealbumin is a protein that's made in your liver and is found in your blood. Prealbumin is used to make other proteins and helps carry thyroid hormones and vitamin A through your bloodstream. It also helps control how your body uses energy.

If your prealbumin levels are lower than normal, it may be a sign of malnutrition. Malnutrition is a condition where your body doesn't get enough of the nutrients that you need for good health, such as protein, vitamins, and minerals. Children with malnutrition may not grow and develop normally.

Malnutrition can happen if you:

• Don't eat enough food
• Eat enough, but don't eat healthy, nutritious foods
• Have problems absorbing nutrients
• Have an increased need for nutrients because of infection, a serious injury, cancer, recovery after surgery, or other conditions

Other names: thyroxine binding prealbumin, PA, transthyretin test, transthyretin, tryptophan-rich prealbumin

What is it used for?

Until recently, a prealbumin test was used to help:

• Find out if you are getting enough nutrients, especially protein, in your diet
• Check for nutrition problems if you have a risk of malnutrition because you:
  • Are in the hospital with certain diseases
  • Have had surgery
  • Have a serious or chronic (long-lasting) illness
  • Get dialysis treatment for kidney disease and need to avoid eating many types of food
  • Are fed by parenteral nutrition (artificial feeding), which means that you get a nutritional liquid through an intravenous (IV) tube

While some health care professionals still use the prealbumin test for these reasons, many now believe that changes in prealbumin can actually be a sign of inflammation (swelling), infection, or injury. So, they think that this test should not be used to measure your nutrition levels or test for malnutrition anymore. That being said, there are health care professionals who think the test can still be helpful to check for malnutrition in people who are very sick or hospitalized.

Why do I need a prealbumin blood test?

Your health care provider may order a prealbumin test to help diagnose and monitor problems with your nutritional health if they think the test is still helpful for this. You may also need this test before surgery or if you have symptoms of malnutrition, such as:

• Weight loss
• Weakness
• Dizziness
• Dry skin
• Dry, brittle hair and/or hair loss
• Feeling cold
• Aching joints

What happens during a prealbumin blood test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a prealbumin test. Certain medicines may affect the results of your test. Tell your provider about everything you take. But don't stop taking any medicines unless your provider tells you to.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Prealbumin levels that are lower than normal may happen with:

• Malnutrition
• Inflammation
• Trauma, such as a burn injury
• Serious or long-term illness, such as cancer
• Liver disease
• Serious infection
• Hyperthyroidism
• Certain digestive diseases

If you have low prealbumin levels and you are ill, injured, or recovering from surgery, it may be difficult to know exactly what is causing the low levels. Your provider may need to do other tests to find out more about your nutritional health.

Prealbumin levels that are higher than normal may happen with several conditions, including:

• Hodgkin disease
• Kidney failure
• Alcohol use disorder (AUD)
• High-dose corticosteroid therapy

Prealbumin testing is not used to diagnose or monitor these conditions. If you have high prealbumin levels, your provider may order other tests to diagnose your condition.

If your prealbumin levels are not normal, it doesn't always mean you have a condition that needs treatment. Certain medicines and pregnancy can affect your prealbumin levels. If you have questions about your results, talk with your provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a prealbumin blood test?

Remember, some medical experts don't think a prealbumin test is the best way to diagnose or monitor malnutrition. That's because other medical conditions can cause low prealbumin levels.

More research is needed to understand how prealbumin works in the body and what abnormal test results may mean. But many providers still find prealbumin blood tests useful for monitoring nutrition, especially in people who are seriously ill or in the hospital.