Hemophilia is a bleeding disorder usually inherited, meaning it’s passed down through families. If you have a family history of unexplained bleeding or are concerned about potential bleeding issues, understanding the Hemophilia Diagnosis Test is crucial. Early diagnosis is key to managing hemophilia and ensuring a healthy life. This article will explain who should consider getting tested for hemophilia, when testing is recommended, and the types of tests used for diagnosis.
Who Should Get Tested for Hemophilia?
Deciding who should undergo a hemophilia diagnosis test often depends on family history and the presence of bleeding symptoms.
Families with a History of Hemophilia
A significant indicator for a hemophilia diagnosis test is a family history of bleeding disorders. If your family has a history of excessive bleeding after surgery or injury, or unexplained deaths among male relatives like brothers, maternal uncles, grandfathers, or cousins, it’s important to discuss this with a doctor. A healthcare provider will typically take a detailed family history to assess the possibility of a bleeding disorder like hemophilia within your family lineage.
Certain newborns are particularly recommended for a hemophilia diagnosis test soon after birth. These include:
- Babies born into families with a known history of hemophilia.
- Infants whose mothers are confirmed carriers of the hemophilia gene.
- Newborns who exhibit bleeding symptoms at birth.
Umbilical cord blood testing is a common method for newborn screening. However, it’s worth noting that this test is more effective at detecting low levels of factor VIII (associated with hemophilia A) than factor IX (associated with hemophilia B). Factor IX levels naturally develop more slowly and may not reach normal levels until a baby is around 6 months old. Therefore, a mildly low factor IX level at birth might not definitively indicate hemophilia B, and a repeat hemophilia diagnosis test may be necessary as the baby gets older.
Alt text: A gloved hand carefully holds a vial of blood, ready for hemophilia diagnosis testing in a laboratory setting.
Families with No Previous History of Hemophilia
It’s important to know that approximately 1 in 3 babies diagnosed with hemophilia have no prior family history of the condition. This occurs due to spontaneous genetic mutations. A doctor may consider a hemophilia diagnosis test for a newborn even without family history if certain bleeding signs are observed, such as:
- Prolonged bleeding following circumcision.
- Excessive bleeding after routine blood draws or heel sticks (common newborn screening procedures).
- Bleeding within the head (scalp or brain) resulting from a difficult delivery or the use of delivery assistance tools like vacuum extractors or forceps.
- The appearance of unusual, raised bruises or a surprisingly large number of bruises on the infant.
If hemophilia is not diagnosed in the newborn period, parents may notice unusual bruising as the child begins to move around, stand, or crawl.
Individuals with severe hemophilia often experience significant bleeding problems early in life and are frequently diagnosed within the first year. However, those with milder forms of hemophilia might not receive a diagnosis until later in childhood or even adulthood, often when they experience unusual bleeding after an injury or surgery.
When to Get Tested or Screened
For individuals with a family history of hemophilia, or those who suspect they might be carriers, it’s common to request a hemophilia diagnosis test for their baby soon after birth. However, testing can be performed at any age if there are concerns about bleeding symptoms or if an individual wants to determine their carrier status or confirm a diagnosis.
Types of Tests
The hemophilia diagnosis test process involves two main categories of blood tests: screening tests and clotting factor tests.
Screening Tests
Screening tests are initial blood tests used to assess if blood is clotting correctly. These tests can indicate a potential bleeding disorder but do not definitively diagnose hemophilia or its type. Common screening tests include:
Complete Blood Count (CBC)
A CBC measures various components of the blood, including hemoglobin levels, red blood cell size and count, and the number of different types of white blood cells and platelets. In people with hemophilia, the CBC is often normal. However, in cases of significant bleeding, hemoglobin and red blood cell counts may be low, indicating anemia. While not a direct hemophilia diagnosis test, it’s a routine part of initial assessment.
Activated Partial Thromboplastin Time (APTT) Test
The APTT test measures how long it takes for blood to clot. It specifically evaluates the clotting ability of factors VIII, IX, XI, and XII. If any of these factors are deficient, as in hemophilia A (factor VIII deficiency) or hemophilia B (factor IX deficiency), the blood will take longer than normal to clot. An extended clotting time on the APTT test is a strong indicator for further hemophilia diagnosis test.
Prothrombin Time (PT) Test
Similar to the APTT, the PT test also measures blood clotting time. However, it primarily assesses the clotting ability of factors I, II, V, VII, and X. In most individuals with hemophilia A and B, the PT test results are typically normal because these forms of hemophilia primarily affect factors VIII and IX, which are more sensitively detected by the APTT test. Therefore, the PT test is less directly relevant as a hemophilia diagnosis test for hemophilia A and B but is used to rule out other clotting disorders.
Fibrinogen Test
This test measures the level of fibrinogen (clotting factor I) in the blood. It’s used to further evaluate a patient’s ability to form blood clots and is often ordered alongside other clotting tests or when APTT or PT results are abnormal. While fibrinogen deficiency is a separate condition, this test can be part of a broader evaluation when investigating potential bleeding disorders.
Clotting Factor Tests
Clotting factor tests, also known as factor assays, are essential for a definitive hemophilia diagnosis test. These tests measure the specific activity levels of clotting factors VIII and IX in the blood. By quantifying the levels of these factors, doctors can:
- Confirm the diagnosis of hemophilia.
- Determine the type of hemophilia (A or B).
- Assess the severity of hemophilia based on the factor level.
Knowing the precise type and severity of hemophilia is crucial for developing an individualized and effective treatment plan.
Hemophilia Severity Classification
The severity of hemophilia is classified based on the baseline clotting factor activity, measured as a percentage of the normal level. Normal factor levels are around 100%, with a typical normal range defined as 50% to 150%. The International Society on Thrombosis and Hemostasis (ISTH) has established the following severity categories:
| Severity | Levels of factor VIII or factor IX in the blood |
|---|---|
| Mild Hemophilia | Greater than 5% but less than 40% |
| Moderate Hemophilia | 1% to 5% |
| Severe Hemophilia | Less than 1% |
It’s important to note that women and girls with an abnormal hemophilia gene can also be categorized based on their factor levels. Those with factor levels ≥40% and bleeding symptoms are termed “symptomatic carriers,” while those with factor levels ≥40% without bleeding symptoms are “asymptomatic carriers.”
Understanding the hemophilia diagnosis test process empowers individuals and families to take proactive steps in managing potential bleeding disorders. If you have concerns about hemophilia, consulting with a healthcare professional is the first step towards appropriate testing and care.
