View results

When do people with hemophilia develop inhibitors?

Inhibitors can only develop after replacement factor has been used. They do not exist at birth. Most inhibitors develop in the first 9 to 50 injections. Inhibitors may appear after years of treatment, but this is rare.


Signs that there is an inhibitor

When treating a bleed, watch for these signs:

•Treatment is taking longer to stop a bleed
•Treatment is not working
•You need higher doses or more treatments

There may not be any symptoms of inhibitors. They may be found through routine blood tests conducted by your HTC.

What tests are used?

A blood test called the Bethesda inhibitor assay is used to detect inhibitors. The test uses Bethesda units (BUs) to measure the amount of inhibitors. This strength is called a Bethesda titer. Stronger inhibitors mean higher titers (high BU). You always want titers to be low.