What causes hairy cell leukemia?

Hairy cell leukemia is caused by a specific mutation in the BRAF gene, particularly the BRAF V600E mutation, which is found in nearly all patients with this condition. This genetic change causes B-lymphocytes to grow abnormally and develop characteristic hair-like projections on their surface. While the exact trigger for this mutation is unknown, the BRAF mutation disrupts normal cell growth signals, leading to the accumulation of cancerous white blood cells in the bone marrow and spleen.

What is the best test for hairy cell leukemia?

The BRAF Mutation Analysis is the most important test for hairy cell leukemia because it detects the BRAF V600E genetic mutation present in almost all cases of this rare blood cancer. This specialized blood test identifies the specific genetic change in B-lymphocytes that confirms the diagnosis and distinguishes hairy cell leukemia from other blood disorders. The test also provides valuable information for treatment planning, as targeted therapies are available for BRAF-positive cancers. Your healthcare provider may also order a complete blood count, blood cell analysis, and bone marrow examination to assess the extent of the disease.

When should I get tested for hairy cell leukemia?

You should get tested if you experience unexplained fatigue, frequent infections, easy bruising or bleeding, or notice an enlarged spleen or abdominal fullness. Testing is also important if routine blood work shows abnormal white blood cell counts, low red blood cell counts (anemia), or low platelet counts without another clear cause. Because hairy cell leukemia is slow-growing, symptoms may develop gradually over months or years, making early detection through blood testing crucial for timely treatment.

What are the symptoms of hairy cell leukemia?

Symptoms of hairy cell leukemia include persistent fatigue and weakness, frequent infections due to low white blood cell counts, easy bruising or bleeding from low platelet levels, and pain or fullness in the upper left abdomen from an enlarged spleen. Many people also experience unexplained weight loss, night sweats, and swollen lymph nodes. Some individuals may have no symptoms initially and discover the condition through routine blood work that shows abnormal cell counts.

Who is at risk for hairy cell leukemia?

Hairy cell leukemia primarily affects middle-aged and older adults, with most cases diagnosed in people over 50 years old. Men are four times more likely to develop this condition than women. While the exact cause is unknown, exposure to certain chemicals or radiation may increase risk, though most people with hairy cell leukemia have no identifiable risk factors. This rare cancer accounts for only about 2% of all leukemia cases.

What happens if hairy cell leukemia is left untreated?

If left untreated, hairy cell leukemia can lead to severe complications including life-threatening infections due to very low white blood cell counts, serious bleeding problems from critically low platelet levels, and severe anemia causing extreme fatigue and organ damage. The cancerous cells continue to accumulate in the bone marrow and spleen, which can become dangerously enlarged and cause abdominal pain or rupture. Early diagnosis through BRAF mutation testing and appropriate treatment can prevent these complications and achieve long-term remission in most patients.

Can hairy cell leukemia be diagnosed with a blood test?

Yes, hairy cell leukemia can be diagnosed with blood tests, particularly the BRAF Mutation Analysis that detects the characteristic genetic mutation present in nearly all cases. A complete blood count typically shows abnormal cell levels, and microscopic examination of blood cells reveals the distinctive hair-like projections on affected lymphocytes. While bone marrow examination provides additional confirmation, the BRAF mutation test through blood work is a powerful diagnostic tool that is less invasive and highly specific for this condition.

How is hairy cell leukemia treated?

Hairy cell leukemia is treated with chemotherapy drugs like cladribine or pentostatin, which can achieve long-term remission in the majority of patients, often after just one course of treatment. For patients with the BRAF mutation, targeted therapy with BRAF inhibitors like vemurafenib offers another treatment option. Some people with mild disease may not need immediate treatment and can be monitored with regular blood tests. Splenectomy (surgical removal of the spleen) may be recommended in certain cases, and newer immunotherapy approaches are being studied for resistant or relapsed disease.

How can I prevent hairy cell leukemia?

There is no known way to prevent hairy cell leukemia because the exact cause of the BRAF gene mutation is not understood. Unlike some cancers, hairy cell leukemia is not linked to lifestyle factors like smoking, diet, or exercise that can be modified. The best approach is awareness of symptoms and getting regular health checkups, especially if you are in a higher-risk age group. Early detection through blood testing can lead to prompt treatment and better outcomes.

What can I do at home for hairy cell leukemia?

While hairy cell leukemia requires medical treatment, you can support your health at home by preventing infections through good hand hygiene, avoiding sick contacts, and staying up to date on vaccinations as recommended by your doctor. Eating a nutritious diet rich in fruits, vegetables, and lean protein helps maintain strength and supports your immune system. Getting adequate rest, managing stress, and staying physically active within your energy limits can improve quality of life. Always inform your healthcare team about any new symptoms, and attend all scheduled appointments to monitor your blood counts and treatment response.

Getting your blood test with us is easy, private & backed by the power of science.Long story short: In the test options, use the filters or search box to narrow your choices and find the test you want. If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test. Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout. If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want. When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system. Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy! If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

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Hairy Cell Leukemia Blood Test

What is Hairy Cell Leukemia?

Hairy cell leukemia is a rare, slow-growing blood cancer that affects B-lymphocytes, a type of white blood cell. It is caused by a BRAF V600E gene mutation that triggers abnormal growth of B-lymphocytes with distinctive hair-like projections. The BRAF Mutation Analysis is the most important test for diagnosis because this genetic mutation is present in nearly all hairy cell leukemia cases.

Written by Private MD Labs Medical Team

Last updated: December 30, 2025

Getting your blood test with us is easy, private & backed by the power of science.

Long story short:

In the test options, use the filters or search box to narrow your choices and find the test you want.
If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test.
Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout.
If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want.
When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system.
Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way.
You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!

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