Finding out you have a rare disease like amyloidosis can be confusing and scary, especially if you’ve never heard of it. And many people haven’t. It’s not well known, which is why it’s often diagnosed late or missed altogether.

Amyloid light-chain (AL) amyloidosis is the most common type, affecting about 4,500 people in the United States each year. Blood tests can help doctors spot signs of the disease and decide what to do next, but a biopsy is needed to confirm it. In a biopsy, a small sample of tissue is removed from your body so doctors can check it under a microscope for amyloid protein deposits. They usually look in places like fat, bone marrow, or organs.

Several types of blood tests may be used to help diagnose amyloidosis. If you’re living with the disease, these tests also help your doctors track your overall health and monitor how well your treatment is working.

What Is Amyloidosis?

Proteins normally fold into precise shapes that help them do specific jobs in the body. In amyloidosis, some abnormal proteins misfold and stick together, forming amyloid deposits. These deposits build up in organs and tissues, much like debris clogging a pipe. Over time, this makes it harder for those organs to work properly.

The body doesn't normally make amyloid. It forms when certain proteins change shape and build up because of a genetic abnormality or other health conditions. Amyloid deposits or buildup can affect the liver, spleen, nervous system, and gastrointestinal tract. The most commonly affected organs are the kidneys and the heart.

Amyloidosis isn’t just one disease. It refers to a group of conditions caused by different types of amyloid proteins. Each type can lead to a different form of amyloidosis, including:

• AL amyloidosis — Develops when abnormal proteins called light chains build up in the body’s tissues and organs
• AA amyloidosis — Also called secondary amyloidosis, it can happen when long-term inflammation causes the liver to make abnormal serum amyloid A protein
• Hereditary ATTR amyloidosis — Is passed down through families and is caused by a mutation (change) in a gene that makes the transthyretin (TTR) protein
• Wild-type ATTR amyloidosis — Develops from the TTR protein, but doesn’t involve mutations in the TTR gene

Once your healthcare team has diagnosed the type of amyloidosis you have, they can choose the right treatment options to target the specific amyloid proteins.

Blood Tests for Diagnosing Amyloidosis

Doctors use different blood tests to help diagnose amyloidosis. While no single blood test can confirm it, the results can tell your doctor more about the condition.

Along with blood tests and a biopsy, your doctors may order other tests. These can include urine tests to check your kidneys, echocardiograms to look at your heart, and nerve tests to see if your nerves are damaged.

Complete Blood Count

A complete blood count (CBC) is a standard blood test used to determine the levels of different types of blood cells in the body, including red blood cells, white blood cells, and platelets. Although CBC numbers can’t diagnose amyloidosis, they can help rule out other causes of a person’s signs and symptoms.

Some amyloidosis treatments can affect how many blood cells your bone marrow makes or how well they work. Doctors may order regular CBCs to check your blood cells during treatment and adjust your medications if needed.

Serum Protein Electrophoresis

Immunoglobulins are proteins that act as antibodies in the blood. In amyloidosis, the body makes abnormal immunoglobulins called monoclonal proteins, which can form amyloids. The serum protein electrophoresis (SPEP) test examines your blood for these proteins. Certain types of amyloidosis, particularly AL amyloidosis, can result in high levels of monoclonal proteins, so the results of a SPEP test can help doctors better understand what’s going on in a person’s body.

You might have a similar but more sensitive blood or urine test after your SPEP test, called immunofixation electrophoresis (IFE). This test looks for specific abnormal proteins, called monoclonal proteins — proteins made by a single type of immune cell — that can be a sign of AL amyloidosis.

Still, finding monoclonal proteins isn’t enough to diagnose amyloidosis. Doctors also look at your symptoms and other test results to get the full picture.

Serum-Free Light Chain Assay

A serum-free light chain (SFLC) assay checks for certain proteins in your blood. Immunoglobulin light chains are parts of these proteins that are made up of two parts: light chains and heavy chains. Normally, light chains attach to heavy chains to form complete antibodies. When the light chains don’t bind to their heavy chain partners, it may be a sign of a problem with plasma cells in your bone marrow, which can point to AL amyloidosis.

The SFLC assay looks for excess free light chains in the blood. This test doesn’t just help with diagnosis — it can also help doctors monitor the condition over time. If the numbers remain stable, a person’s amyloidosis isn’t getting worse. If the numbers improve, the person is likely responding well to medication or other treatments. If free light chain levels are elevated, it could mean that the disease is progressing or that your current treatment may need adjustment, such as a higher dose of medication or a new therapeutic approach.

By looking at the results from the SPEP, IFE, and SFLC tests together, your doctor can get a clear and accurate picture. This is important for finding and diagnosing certain types of amyloidosis, especially AL amyloidosis.

Kidney Function Tests

Because amyloidosis often affects the kidneys, doctors may run tests to see if they are working properly. Reduced kidney function doesn’t always mean you have amyloidosis, but it can be an important clue.

If you’ve been diagnosed with amyloidosis, your doctor will check your kidney function regularly. This often includes blood tests to make sure that your kidneys aren’t getting worse. For example, your doctors will look at the levels of creatinine and urea in your blood. Having high levels of these substances can mean that your kidneys may not be working as well as they should.

Liver Function Tests

Your doctor may want to monitor your liver function if you’ve been diagnosed with amyloidosis. Doctors may look for alkaline phosphatase (ALP) in your blood. ALP is an enzyme made in the liver and other parts of the body. High levels of ALP may be a sign that amyloidosis is affecting the liver.

Heart Function Tests

The heart is another organ that’s often affected by amyloidosis, and this can have a serious impact on your health. To check how well your heart is working, your doctor may run blood tests for certain heart-related substances, called cardiac biomarkers. These include troponin T or troponin I, which can show heart muscle damage, and brain natriuretic peptide (BNP) or NT-proBNP (which stands for N-terminal pro-BNP), which go up when the heart is under stress.

Some doctors and labs will measure all of these biomarkers, while others may use one or two to reflect overall heart health. These tests alone can’t diagnose amyloidosis, but they provide helpful information. They also allow your doctor to keep track of your heart function over time.

Genetic Tests

Certain genetic patterns can put you at risk for amyloidosis. If it seems likely that you have amyloidosis, and doctors want to determine what type you have, they may check a sample of your blood for a mutation in the transthyretin (TTR) gene.

Genetic testing is a key part of diagnosing genetic forms of amyloidosis, such as hereditary amyloid transthyretin (hATTR) amyloidosis.

Ask Your Doctor

The right blood tests can give your doctors important information to help diagnose and manage amyloidosis. While no single test can confirm the condition on its own, using several tests together can help paint a clearer picture. These tests also help your care team track your health and see how well treatment is working. If you have questions about your test results, don’t hesitate to ask your doctor.

Find Your Team

On MyAmyloidosisTeam, the social network for people with amyloidosis and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with amyloidosis.

Have you had blood tests for amyloidosis? How have blood tests helped you understand your condition? Share your experience in the comments below, or start a conversation by posting on your Activities page.