Since hemophilia runs in families and is more frequent in males, diagnosis is usually made early in life. After birth, those with family members with hemophilia typically ask for a test to ensure that their baby boys do not have the disease.
The diagnosis starts by performing a few blood tests to evaluate the clotting function. If clotting tests are not normal, they proceed to use more specific tests to assess the disorder’s cause. They are clotting factor tests and help doctors to locate which clotting factor is absent or abnormal, thus diagnosing the type of hemophilia.
The workup should include the following tests:
- Complete blood count: In this test, it is essential to measure hemoglobin levels, the number of red blood cells, and their size. In most cases, CBC is normal, but sometimes it may show anemia, especially after uncontrolled bleeding episodes.
- Activated Partial Thromboplastin Time Test: This test evaluates the clotting ability of several factors in the blood (FVIII, FIX, FXI, and FXII). Having a deficient level of these clotting factors is the first step to diagnosing hemophilia A or hemophilia B. Since this test does not differentiate FVIII from FIX abnormalities, other tests must make the distinction.
- Prothrombin Time Test: This test evaluates the clotting ability of several factors in the blood (FI, FII, FV, FVII, FX). These tests are usually normal in patients with hemophilia, but the test should be taken to rule out other diseases.
- Fibrinogen Test: This test evaluates the clotting factor I by itself and helps doctors evaluate the patient if he has an abnormal result in any of the tests above.
- Clotting factor tests: In patients with an abnormal result in clotting tests, a clotting factor test is then performed to precisely determine which clotting factor is causing their bleeding disorder. This test is important to differentiate hemophilia A from hemophilia B. It is also an accurate measure of the severity of the condition. When FVIII and FIX are 50-100%, the individual is normal. We can diagnose mild hemophilia when results are lower than 50%. Moderate hemophilia is diagnosed when FVIII or FIX levels are shorter than 5%. And severe hemophilia is diagnosed with clotting factor levels lower than 1%.
- Testing for inhibitors: This exam is usually performed in moderate and severe hemophilia cases and patients who do not have an appropriate response to treatment. It is commonly measured using the Bethesda method, with a positive result whenever we have 0.6 Bethesda Units (BU) or more. 5 BU or more is associated with more severe disease.
- Radiography: In patients with hemophilia, one of the most common manifestations is associated with joint health. Thus, radiography is important to evaluate the joints. Acute hemarthrosis is difficult to consider, but we can assess chronic degenerative joint disease with radiographs. It is essential to assess cartilage damage, bone cyst formation, synovial hypertrophy, and other joint problems commonly found in hemophilia.