Thalassaemia Test: Everything You Need To Know

What is thalassaemia and what causes it?

Thalassaemia is a genetic blood disorder that affects the body’s ability to produce haemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body. So, if you have thalassaemia, your body produces fewer healthy haemoglobin proteins, and your bone marrow produces fewer healthy red blood cells. Not having enough healthy red blood cells can deprive your body's cells of the oxygen and cause anaemia.

The condition is caused by mutations in the genes that control haemoglobin production. Haemoglobin consists of four protein chains, two alpha-globin protein chains and two beta-globin protein chains. Each chain contains genetic information, or genes, passed down from your parents. If any of these genes are defective or missing, it causes thalassaemia. 

People with a family history of thalassaemia or those from a Mediterranean, Middle Eastern, South Asian, or African background are at higher risk for thalassaemia, as these populations have a higher prevalence of the gene mutations responsible for the disorder.

What are the different types of thalassaemia?

Thalassaemia is usually classified as either alpha or beta thalassaemia, depending on whether the alpha-globin or beta-globin gene is affected. When beta-globin is involved, the condition can be further categorised as a trait, minor, intermedia, or major, depending on how severe the symptoms are.

Alpha thalassaemia

In specific cases, a special DNA test can test for this condition. Alpha thalassaemia happens when one or more of the four genes needed to make a part of haemoglobin called alpha-globin don't work properly. If only one gene is affected, you are considered a "silent carrier" and usually experience no symptoms. If you have two affected genes, you might experience mild anaemia without noticing any problems. 

You may require frequent blood transfusions and suffer from moderate to severe anaemia if three genes are impacted. If all four genes are missing or not functioning properly, the condition is usually life-threatening before or shortly after birth.

Beta thalassaemia

This occurs when you inherit two beta-globin genes, one from each parent. The severity of your anaemia symptoms depends on the number of defective genes and the specific part of the beta globin protein chain that contains the defect.

• Thalassaemia trait or thalassaemia minor:

  • This means that you might either experience mild symptoms of anaemia or have no symptoms at all. Hence, you may not need treatment.

• Thalassaemia intermedia:

  • This is a form of beta-thalassaemia where individuals experience a less severe form of anaemia than beta-thalassaemia major, but not severe enough to require regular transfusions.

• Thalassaemia major:

  • This is the most severe form of anaemia, which usually requires regular treatment.

  • Having thalassaemia major means that an individual has inherited two thalassaemia genes, one from each parent.

  • A baby with this condition may appear normal at birth. However, they may suffer from severe anaemia within the first one to two years of life, which can lead to poor growth and development, as well as a shorter life expectancy.

What are the symptoms of thalassaemia?

Symptoms vary depending on the type and severity of thalassaemia. Common symptoms include:

• Fatigue and weakness
• Shortness of breath
• Pale skin or yellowing of skin and eyes (jaundice)
• Slow growth and delayed puberty in children
• Enlarged spleen or liver
• Bone issues such as osteoporosis or bone deformities, particularly in the face and skull
• Dark urine
• Poor appetite

While people with thalassaemia minor may have few or no symptoms, those with thalassaemia major experience more severe and persistent health issues.

If these symptoms are affecting your daily life, don't hesitate to request an appointment with Thomson Medical. Our specialists can help you with further examination and may perform thalassaemia tests to confirm your diagnosis.

When should I get tested for thalassaemia?

You may consider getting tested for thalassaemia under several circumstances:

• Have a family history of thalassaemia:

  • People with close relatives who have thalassaemia or who are carriers should be screened, as the condition is inherited.

• Planning to start a family:

  • It’s recommended that both partners are screened before conception or during early pregnancy, particularly if you’re from an ethnic group with a higher prevalence of thalassaemia. The test helps assess the risk of passing the condition on to the infant. 

  • This is because children born with thalassaemia major can experience severe anaemia throughout their lives, requiring regular blood transfusions. 

• During pregnancy:

  • Thalassaemia screening is often recommended as part of routine antenatal care, particularly for couples at risk, to identify carrier status early and provide appropriate counselling.

• If you have symptoms of unexplained anaemia:

  • People presenting with microcytic anaemia (small red blood cells) that is not due to iron deficiency should be evaluated for thalassaemia, as it is a common cause of this type of anaemia.

• If you belong to a high-risk population:

  • Individuals from Mediterranean, Middle Eastern, South Asian, or Southeast Asian backgrounds have a higher risk of being carriers and should consider screening, even without a family history.

• If you are advised by your doctor:

  • Sometimes, routine blood tests may reveal abnormal red blood cell indices, such as low mean corpuscular volume (MCV) or mean corpuscular haemoglobin (MCH), prompting your doctor to recommend further testing for thalassaemia.

Early detection through screening is crucial for making informed reproductive choices, as well as for the timely management of any health implications related to thalassaemia.

How do I test for thalassaemia?

Testing for thalassaemia typically involves the following blood tests:

• Complete blood count:

  • Measures haemoglobin levels and identifies abnormalities in red blood cells.

• Haemoglobin electrophoresis:

  • This blood test separates and identifies the different types of haemoglobin in the blood to determine the presence and type of thalassaemia.

• Genetic testing:

  • Analyses DNA to identify mutations associated with thalassaemia. This test can determine if an individual is a carrier or if has the condition.

People with a family history of thalassaemia or those planning a family should consider testing, which is widely available at polyclinics and hospitals.

What happens if I'm pregnant and have thalassaemia?

If you are pregnant and have thalassaemia, it is important to consult your doctor early. You may be referred for an antenatal screening to find out whether your unborn child has thalassaemia or genetic counselling to assess the risk of passing the condition on to your baby. 

Antenatal screening, such as chorionic villus sampling (CVS) or amniocentesis, can determine if your baby has inherited thalassaemia. Pregnant women with thalassaemia may require additional monitoring and, in some cases, blood transfusions to manage anaemia and prevent complications.

How do I prepare for the test?

Generally, a thalassaemia blood test doesn't require any special preparation. However, you should inform your healthcare provider of any medications you are taking or if you have had any recent blood transfusion, as it can affect your test results. It is best to consult your doctor and follow any specific instructions provided by your clinic.

What can I expect during the test?

A thalassaemia blood test usually involves a simple blood draw from your arm. The procedure is quick and may cause minor discomfort or bruising at the puncture site. The sample is then sent to a laboratory for analysis, and results are typically available within a few days.

How do I interpret the results?

Your doctor will take a look at the analysis sent by the laboratory and review your test results with you. Some key indicators include:

• Haemoglobin levels:

  • Low levels may indicate anaemia

• Red blood cell indices (e.g., MCV):

  • Help differentiate thalassaemia from other causes of anaemia

If you are found to be a carrier (thalassaemia trait), you may have mild anaemia but generally do not require treatment. If you have thalassaemia major, your doctor will discuss management options, which may include regular transfusions and iron chelation therapy.

How much does a thalassaemia test cost?

The cost of a thalassaemia test in Singapore typically ranges from $18 to $200 depending on the type of test you get and your healthcare provider. More detailed genetic testing will incur additional costs. 

However, subsidies may be available at public healthcare institutions. For the best guide, check with both your healthcare provider and insurance provider on the cost of the type of test you need and whether you are eligible for any subsidies.

FAQ

What is the test for thalassaemia?

The main tests for thalassaemia are a full blood count (FBC), haemoglobin electrophoresis, and genetic testing. These help diagnose the condition and determine its type and severity.

What is MCV in a blood test?

MCV stands for Mean Corpuscular Volume. It measures the average size of your red blood cells and helps doctors classify different types of anaemia. Thalassaemia and iron deficiency often cause low MCV or microcytic anaemia.

How to confirm beta thalassaemia?

Beta thalassaemia is diagnosed using a mix of blood tests (FBC and haemoglobin electrophoresis) and genetic tests to find changes in the beta globin genes.

Do people with thalassaemia need more sleep?

Some studies have found that people with thalassaemia, especially children with beta thalassaemia, may experience excessive daytime sleepiness, possibly due to chronic anaemia and disrupted sleep patterns.

What does thalassaemia do to a person?

Thalassaemia can cause chronic anaemia, fatigue, delayed growth, bone deformities, and increased risk of infections. Severe forms may require regular blood transfusions and can lead to complications such as iron overload, affecting the heart, liver, and endocrine system.

Can thalassaemia patients live a normal life?

Many people with thalassaemia minor live normal, healthy lives without symptoms. Those with thalassaemia major require ongoing medical care, but advances in treatment have improved life expectancy and quality of life significantly.

What is the cause of thalassaemia?

Thalassaemia is caused by inherited mutations in the genes responsible for haemoglobin production. It is not caused by lifestyle or environmental factors.

Is thalassaemia curable?

Currently, the only potential cure for thalassaemia major is a bone marrow or stem cell transplant, which is not suitable for all patients. Most people manage the condition with regular transfusions and medication to control iron levels.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.