What is Bone Marrow Test? Purpose, Levels/Procedure & Results

A bone marrow test is a medical procedure that examines the soft, spongy tissue inside your bones where blood cells are made. Your doctor takes a small sample of this tissue to check how well your body produces blood cells and to look for signs of blood disorders, infections, or certain cancers.

Think of bone marrow as your body's blood cell factory. When doctors need to understand why your blood counts are abnormal or suspect a blood-related condition, they examine this factory directly. The test provides crucial information that blood tests alone cannot reveal.

What is bone marrow?

Bone marrow is the soft, jelly-like tissue found inside the hollow spaces of your larger bones, especially in your hip bones, breastbone, and spine. This remarkable tissue serves as your body's primary blood cell production center, constantly creating red blood cells, white blood cells, and platelets.

Your bone marrow contains two main types of tissue. Red marrow actively produces blood cells, while yellow marrow stores fat and can convert to red marrow when your body needs more blood cells. As you age, more of your red marrow naturally converts to yellow marrow.

The process of making blood cells in your bone marrow is called hematopoiesis. Special cells called stem cells divide and mature into different types of blood cells before entering your bloodstream. This process happens continuously throughout your life, replacing old and damaged blood cells.

Why is bone marrow test done?

Doctors recommend bone marrow tests when they need to investigate unexplained changes in your blood cell counts or suspect certain blood disorders. The test helps diagnose conditions that affect blood cell production and provides detailed information about your bone marrow's health and function.

Your doctor might suggest this test if you have persistent fatigue, unexplained infections, or unusual bleeding that could indicate blood cell problems. The test can also help monitor how well treatments for blood disorders are working.

Here are the main reasons doctors order bone marrow tests:

• Diagnosing blood cancers like leukemia, lymphoma, or multiple myeloma
• Investigating unexplained low or high blood cell counts
• Checking for genetic disorders that affect blood cell production
• Monitoring treatment response in blood disorders
• Diagnosing certain infections that affect bone marrow
• Evaluating unexplained anemia or bleeding disorders
• Assessing bone marrow function before stem cell transplant

The test provides information that routine blood tests cannot offer, giving your medical team a complete picture of your blood cell production system.

What is the procedure for bone marrow test?

A bone marrow test actually involves two related procedures: bone marrow aspiration and bone marrow biopsy. During aspiration, your doctor draws out liquid bone marrow, while the biopsy removes a small piece of solid bone marrow tissue for examination.

The procedure typically takes place in a hospital or outpatient clinic and usually lasts about 30 minutes. Most patients receive local anesthesia to numb the area, and some may also get mild sedation to help them relax during the procedure.

Here's what happens during the bone marrow test:

1. You'll lie on your side or stomach, depending on the sample site
2. Your doctor cleans and numbs the skin over your hip bone or breastbone
3. A thin needle is inserted through the skin into the bone
4. Liquid bone marrow is drawn out with a syringe (aspiration)
5. A slightly larger needle removes a small piece of bone with marrow (biopsy)
6. The sample sites are bandaged and you're monitored briefly

You might feel pressure and a brief, sharp pain when the marrow is withdrawn, but the discomfort is usually short-lived. Most people describe it as similar to getting a shot, though slightly more intense.

How to prepare for your bone marrow test?

Preparing for a bone marrow test involves both physical and mental preparation to ensure the procedure goes smoothly. Your doctor will provide specific instructions, but most preparation is straightforward and doesn't require major lifestyle changes.

Let your doctor know about all medications you're taking, especially blood thinners like aspirin or warfarin. You may need to stop certain medications several days before the test to reduce bleeding risk.

Here's how to prepare for your bone marrow test:

• Arrange for someone to drive you home after the procedure
• Eat a light meal before the test unless told otherwise
• Wear comfortable, loose-fitting clothing
• Take any prescribed pre-medication as directed
• Bring a list of all your current medications
• Plan to rest for the remainder of the day after the test

It's completely normal to feel anxious about the procedure. Talk to your healthcare team about any concerns you have, and don't hesitate to ask questions about what to expect.

How to read your bone marrow test results?

Bone marrow test results provide detailed information about your blood cell production and bone marrow health. A pathologist examines your samples under a microscope and may perform additional tests to check for genetic changes or specific markers that indicate disease.

Normal results show healthy bone marrow with appropriate numbers of developing blood cells at different stages of maturity. The cells should appear normal in size, shape, and structure, with no signs of cancer or other abnormalities.

Your results typically include information about:

• Cell counts and percentages of different blood cell types
• Cell appearance and maturity levels
• Presence of abnormal or cancerous cells
• Genetic markers or chromosome changes
• Signs of infection or other disorders
• Overall bone marrow cellularity (how active it is)

Your doctor will explain what your specific results mean for your health and discuss any necessary follow-up care or treatment options. Results can take several days to a week to come back completely.

What are normal bone marrow findings?

Normal bone marrow shows active, healthy blood cell production with cells at various stages of development. The marrow should contain appropriate proportions of red blood cell precursors, white blood cell precursors, and platelet-forming cells called megakaryocytes.

In healthy bone marrow, you'll see immature cells gradually maturing into fully functional blood cells. The cells should have normal shapes, sizes, and internal structures without signs of genetic abnormalities or malignant changes.

Typical normal findings include:

• Balanced production of all blood cell types
• Normal cell appearance and maturation patterns
• Appropriate bone marrow cellularity for your age
• No excess of immature or abnormal cells
• Normal genetic markers and chromosome structure
• Absence of cancer cells or infectious organisms

Normal results don't necessarily mean you're completely healthy, but they do indicate that your bone marrow is functioning properly and producing blood cells normally.

What are abnormal bone marrow findings?

Abnormal bone marrow findings can indicate various conditions affecting blood cell production, from benign disorders to serious cancers. The specific abnormalities help your doctor determine the underlying cause and appropriate treatment approach.

Common abnormal findings include too many or too few cells of certain types, cells that look unusual under the microscope, or the presence of cells that shouldn't normally be in bone marrow. These changes can indicate different types of blood disorders.

Abnormal findings may include:

• Excess immature white blood cells (possible leukemia)
• Reduced overall cell production (bone marrow failure)
• Abnormal cell shapes or sizes (dysplasia)
• Presence of cancer cells from other organs
• Genetic abnormalities in blood cells
• Signs of infection or inflammatory conditions
• Increased iron storage or other metabolic changes

Your doctor will correlate these findings with your symptoms, medical history, and other test results to make an accurate diagnosis and recommend appropriate treatment.

What are the risk factors for abnormal bone marrow?

Several factors can increase your risk of developing bone marrow problems, though many people with risk factors never develop serious conditions. Understanding these factors can help you and your doctor monitor your health more closely.

Age is one of the most significant risk factors, as bone marrow disorders become more common as you get older. Your bone marrow naturally becomes less active with age, and genetic changes accumulate over time.

Here are the main risk factors for bone marrow disorders:

• Advanced age (most blood cancers occur after age 60)
• Previous cancer treatment with chemotherapy or radiation
• Family history of blood disorders or certain genetic conditions
• Exposure to certain chemicals like benzene or pesticides
• Smoking and excessive alcohol consumption
• Certain genetic disorders like Down syndrome
• Immune system disorders or chronic infections
• Previous blood disorders or bone marrow conditions

Having risk factors doesn't mean you'll definitely develop bone marrow problems, but it's important to discuss them with your doctor for appropriate monitoring and preventive care.

What are the possible complications of bone marrow test?

Bone marrow tests are generally safe procedures with low complication rates. Most people experience only mild discomfort and heal completely within a few days. Serious complications are rare but can occur, especially in people with bleeding disorders or compromised immune systems.

The most common issue after a bone marrow test is temporary soreness at the biopsy site, which usually resolves within a few days with over-the-counter pain relievers. Some people may also experience minor bruising around the area.

Possible complications include:

• Bleeding at the biopsy site (usually minor)
• Infection at the needle insertion site
• Prolonged pain or discomfort
• Bruising or swelling around the area
• Rarely, damage to nearby structures
• Allergic reaction to anesthesia (very rare)

Contact your healthcare provider if you experience severe pain, signs of infection like fever or redness, or bleeding that doesn't stop with gentle pressure. Most complications are minor and easily treatable.

When should I see a doctor for bone marrow concerns?

You should see a doctor if you experience persistent symptoms that could indicate blood or bone marrow problems. Many bone marrow disorders develop gradually, so early symptoms might seem mild or unrelated to serious conditions.

Pay attention to symptoms that persist for more than a few weeks or get progressively worse. While these symptoms can have many causes, they sometimes indicate bone marrow problems that need medical evaluation.

See your doctor if you experience:

• Persistent fatigue that doesn't improve with rest
• Frequent infections or slow healing
• Unexplained bruising or bleeding
• Shortness of breath during normal activities
• Bone pain, especially in your back or chest
• Swollen lymph nodes that don't go away
• Unexplained weight loss or night sweats
• Pale skin or feeling weak

Early detection and treatment of bone marrow disorders can significantly improve outcomes, so don't hesitate to discuss concerning symptoms with your healthcare provider.