Understanding Hemophilia: What Age is Hemophilia Usually Diagnosed?

October 1, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), the median age for diagnosing severe hemophilia is 1 month, while for mild hemophilia, it is 36 months. Understanding what age is hemophilia usually diagnosed is key, as the timing often depends on the condition's severity and whether a family history exists.

Quick Summary

The age of hemophilia diagnosis depends on the condition's severity, with severe cases often identified in infancy due to spontaneous bleeding. Milder forms may not be noticed until childhood or even adulthood following a surgery, injury, or dental procedure. A family history can prompt earlier testing, and the diagnosis is confirmed with blood tests measuring clotting factor levels. Early recognition of signs like unusual bleeding or bruising is critical for prompt treatment.

Key Points

Severity Determines Timing: The age of hemophilia diagnosis is primarily dictated by the condition's severity, with severe cases identified in infancy and mild cases often not until later in life.
Family History Matters: A known family history of hemophilia can lead to prenatal or immediate newborn testing, resulting in earlier diagnosis.
Bleeding Events Trigger Diagnosis: Unexpected or excessive bleeding following events like circumcision, minor injuries, surgery, or dental work often leads to diagnosis.
Toddlerhood Reveals Moderate Cases: The increased mobility and activity of toddlers and young children often brings about noticeable signs like persistent bruising, prompting a diagnosis for moderate hemophilia.
Diagnosis Confirmed by Blood Tests: Regardless of age, a hemophilia diagnosis is confirmed through specific blood tests, such as factor assays, that measure the level of clotting factors VIII or IX.
Early Diagnosis Prevents Complications: Prompt diagnosis allows for effective management and prophylactic treatment, which is crucial for preventing long-term complications like joint damage.
Mild Hemophilia Can Appear in Adulthood: Individuals with mild hemophilia may go undiagnosed for many years, with their condition only becoming apparent during a major hemostatic challenge in adulthood.

The Spectrum of Hemophilia: How Severity Influences Diagnosis Age

Hemophilia is a rare inherited bleeding disorder in which the blood doesn't clot properly. This condition is categorized into three levels of severity: mild, moderate, and severe, based on the percentage of clotting factor in a person's blood. The age at which an individual is diagnosed is directly linked to the severity of their condition. Individuals with severe hemophilia experience frequent spontaneous bleeding, making diagnosis very early in life common, while those with milder forms may not be diagnosed until much later after an unusual bleeding event.

Diagnosis Age by Severity

The most significant determinant of when hemophilia is diagnosed is the severity level. Severe cases present with more obvious and frequent bleeding episodes, leading to earlier medical attention. In contrast, mild hemophilia may only cause problems during significant hemostatic challenges, such as surgery or a major injury.

Severe Hemophilia: Diagnosed earliest, often within the first month of life. The median age of diagnosis for severe hemophilia is just 1 month, according to the CDC. Symptoms like excessive bleeding after circumcision, intracranial bleeds, or unusual bruising are often the initial indicators.
Moderate Hemophilia: Typically diagnosed in early childhood, often by age five. Spontaneous bleeding is less frequent than in severe cases but can still occur after minor injuries. A toddler who begins to crawl or walk may exhibit persistent, large bruises that prompt a medical evaluation.
Mild Hemophilia: Diagnosis often occurs much later, sometimes not until adulthood. Individuals with mild hemophilia may not be aware of their condition until a major injury, surgery, or dental procedure results in unexpectedly prolonged bleeding. Excessive bleeding during childbirth or heavy menstrual periods can also lead to a later diagnosis in females.

Factors Influencing the Timing of Diagnosis

Beyond severity, several factors contribute to when a person receives a hemophilia diagnosis.

Family History: A known family history of hemophilia is one of the strongest drivers for early diagnosis. If a mother is a known carrier, doctors can perform prenatal testing or cord blood testing at birth to determine the child's status immediately.
Circumcision: Excessive or prolonged bleeding following a circumcision is a common early sign of severe hemophilia in newborn males, often leading to a prompt diagnosis.
Developmental Milestones: As infants and toddlers begin to become more mobile, their activity level increases the likelihood of minor bumps and falls. For those with moderate hemophilia, this is often when signs like extensive bruising and joint bleeds become apparent, usually between 12 and 18 months of age.
Surgical Procedures: For individuals with mild hemophilia, a routine surgery or tooth extraction can reveal the bleeding disorder, as the body struggles to form a proper clot.

The Diagnostic Process

Diagnosis involves a combination of medical history review, physical examination, and specific blood tests.

Common diagnostic tests include:

Activated Partial Thromboplastin Time (APTT): This test measures how long it takes for a blood sample to clot. An abnormally long APTT is often an indicator of hemophilia.
Clotting Factor Tests (Factor Assays): After an abnormal APTT result, specific factor assays are performed to measure the activity levels of factors VIII and IX, confirming the type and severity of hemophilia.
Genetic Testing: This can confirm the genetic mutation responsible for the condition and is especially useful for families with a known history of the disorder.

Comparison of Hemophilia Severity and Diagnosis Age


Severity	Factor Level	Common Symptoms	Median Age at Diagnosis	Diagnostic Trigger
Severe	<1% of normal	Frequent spontaneous bleeding into joints and muscles, prolonged bleeding from injuries or circumcision, intracranial bleeds	1 month	Spontaneous bleeding or bleeding post-circumcision
Moderate	1%–5% of normal	Occasional spontaneous bleeding, prolonged bleeding after minor injuries or surgery, easy bruising	8 months	Increased activity causing visible bruising or bleeding into joints
Mild	6%–49% of normal	Rarely spontaneous bleeding, prolonged bleeding only after major injury, surgery, or dental work	36 months or later in life	Major surgical or dental procedure

Conclusion: The Importance of Timely Diagnosis

While the age of diagnosis for hemophilia varies significantly depending on severity and individual circumstances, early and accurate detection is crucial for effective management and long-term health. Severe hemophilia often reveals itself in infancy, allowing for immediate treatment and preventive care to minimize the risk of joint damage and other life-threatening complications. For moderate and mild cases, being aware of a family history and watching for unusual bleeding can prevent delays in diagnosis. Comprehensive care, including genetic counseling and regular monitoring, empowers individuals and families to proactively manage the condition and lead full, active lives. The CDC offers extensive resources for those affected by bleeding disorders; for more information, visit the Centers for Disease Control and Prevention website.

Early Intervention and Management

Upon diagnosis, a patient's care team, typically including a hematologist, will create a comprehensive treatment plan. This plan is tailored to the individual's specific severity level and is vital for preventing complications. Severe hemophilia requires regular preventative treatment, known as prophylaxis, where missing clotting factors are infused to prevent bleeding episodes from occurring. For moderate cases, treatment might be needed only around surgical procedures or after an injury, while those with mild hemophilia may only require on-demand treatment in special situations. Education for both patients and caregivers is a critical component of management, focusing on recognizing bleeds, understanding medication protocols, and safe physical activity. Advances in gene therapy are also offering new possibilities for long-term management and potential cures for hemophilia.

Frequently Asked Questions

According to the CDC, the median age for diagnosing severe hemophilia is 1 month. This is often triggered by significant bleeding events early in life, such as excessive bleeding after circumcision or spontaneous bleeds.

Yes, mild hemophilia can often go unnoticed until adulthood. Diagnosis often occurs after an individual experiences unusually prolonged bleeding during a major surgery, a dental procedure, or following a significant injury.

A known family history of hemophilia is a strong predictor of early diagnosis. If a mother is a carrier, prenatal or immediate newborn testing can be performed to determine the baby's status and prepare for appropriate care.

For infants, early signs can include excessive bleeding after circumcision, large and unexplained bruises, bleeding in the brain (intracranial hemorrhage), or joint bleeds.

As toddlers with moderate hemophilia become more active and start crawling or walking, increased bumps and falls can cause noticeable, large bruises or joint swelling. These visible symptoms often prompt parents to seek a medical evaluation, leading to diagnosis.

The diagnosis involves blood tests, including an Activated Partial Thromboplastin Time (APTT) test to measure clotting time, and specific factor assays to determine the activity levels of factors VIII or IX. Genetic testing can also be used to identify the specific mutation.

Yes, while hemophilia is more common in males, females can also have low clotting factor levels and experience bleeding symptoms. Some females are diagnosed later in life, sometimes due to heavy menstrual bleeding, while others may be identified during testing for a family history.