If you or a loved one has been diagnosed with inhibitors, you may have questions or worries about what this means.

It's important to know that you are not alone. Help is available.1

The Good News and the Bad News

The good news is that an inhibitor does not cause more frequent bleeding episodes than those had by people with hemophilia and no inhibitors.3

But, inhibitors are a challenge for people living with hemophilia and inhibitors. They are also a challenge for the doctors, nurses, and hemophilia care teams treating someone with an inhibitor.3

What It Means

When someone with hemophilia has inhibitors, it means that bleeds may be more difficult to control. It does not mean that someone will have bleeds more often.3,4

Living with inhibitors can be easier with knowledge, planning, a few trade-offs, and the right support.1

Suspicion of Inhibitors

Some people with hemophilia form inhibitors when their body doesn't recognize the clotting factor medication taken to help their blood make clots. As a result, the inhibitors stop the factor VIII or factor IX from working.1,13

When factor replacement therapy does not work as well or as quickly as it once did, then your doctor or hemophilia care team might wonder if you have inhibitors — and ask you to take a blood test to see if their suspicions are correct.4,6

Confirming the Diagnosis and Screening

To confirm that someone has inhibitors, a blood test is used. This blood test is called the Nijmegen-modified Bethesda inhibitor assay.4,6

The Nijmegen-modified Bethesda inhibitor test measures the amount of inhibitors in a person's blood. It uses Bethesda units (BU) to measure the level, or titers, of inhibitors in the blood.6

Diagnosis and Treatment

Inhibitors treatment is based on the type of inhibitor a person is diagnosed with.4,6

Inhibitors are diagnosed as low responding or high responding. This diagnosis depends on how strongly a person's immune system acts against factor medication.4,6

Treating High and Low Inhibitor Levels

When someone has a low level of inhibitors (low titer or <5 BU), they might be able to continue using factor replacement. But, the doctor may have to increase the dosage.4,6

When someone has a high level of inhibitors (high titer or ≥5 BU), then it is not likely that factor replacement will be able to work. So, a doctor will recommend other treatment options.4,6

Screening for Inhibitors

After exposure to factor replacement therapy, children should be screened for inhibitors once every 5 days for the first 20 days, then once every 10 days for the next 21 to 50 days, and at least twice annually until 150 exposure days.4

Regardless of a person's age, inhibitors should always be screened:

  • During a yearly visit with a hemophilia care team1,6
  • When treatment is not working as quickly or effectively to stop bleeding1,4
  • Before any surgery or tooth extraction1,4

Look for the Signs

Only a doctor can diagnose and test for inhibitors. But you can help your doctor by looking for these signs when getting treatment6,18:

  • Your usual dose of factor does not control a bleed
  • You experience frequent bleeds while on a regular treatment schedule (breakthrough bleeds) seems to be less effective

If you notice these symptoms, immediately ask your doctor about getting screened.6

Learn about Inhibitor Therapies >>