How Blood Work is Used to Diagnose and Monitor Lymphoma

Understanding Lymphoma

Lymphoma is a type of blood cancer involving the lymphatic system. Lymphoma occurs when white blood cells called lymphocytes grow abnormally and accumulate in lymph nodes or lymphatic tissues.

The two main categories are Hodgkin lymphoma and non-Hodgkin lymphoma. Lymphoma can develop in lymph nodes anywhere in the body including the neck, armpits, groin, chest, and abdomen.

Some common symptoms include swollen lymph nodes, fatigue, unexplained weight loss, fever and night sweats. However, many symptoms overlap with other less serious illnesses, so diagnostic testing is required.

Medical Exams for Lymphoma

If lymphoma is suspected based on risk factors and symptoms, a physician will first perform a physical exam checking all lymph node areas for swelling, and assessing overall symptoms. They will also take a detailed medical history.

From there, doctors can order a variety of tests to help diagnose lymphoma and determine the specific type and stage.

Blood Tests

A complete blood count (CBC) is usually one of the first tests ordered when lymphoma is suspected. This checks levels of different blood cells including:

• - Red blood cells (low in anemia)
• - White blood cells (high or low in cancers)
• - Platelets (low in cancers)

The CBC provides an overview, but many times cannot conclusively diagnose lymphoma from blood work alone if white blood cell counts are normal. Further testing is required.

Biopsy

A lymph node biopsy is the most definitive way to diagnose lymphoma. A sample is taken either by a needle biopsy or full surgical biopsy. The lymph node tissue is examined under a microscope for cancerous cell characteristics.

Immunohistochemistry and other special stains help identify specific proteins on the lymphocytes to categorize them as Hodgkin or various non-Hodgkin lymphoma subtypes.

Bone Marrow Biopsy

Lymphoma often spreads to the bone marrow. A bone marrow biopsy and aspiration sample may be done to see if the marrow is involved. This also helps determine the lymphoma stage.

The sample is viewed under a microscope and analyzed using flow cytometry and cytogenetics. These techniques identify specific lymphoma cell features and DNA characteristics.

Imaging Tests

Imaging tests allow doctors to see areas affected by lymphoma in the body:

• - CT scan - detailed cross-sectional x-ray images.
• - PET scan - visualizes metabolic activity and lymphoma spread.
• - Ultrasound - uses sound waves to image soft tissues and lymph nodes.
• - MRI scan - radio waves and magnets provide whole body 3D imaging.

These tests identify areas of enlarged lymph nodes or organ involvement both in diagnosing lymphoma and tracking response to treatment.

Other Tests

Chest x-rays and other radiographs help view swollen lymph nodes and organ involvement. Endoscopies use cameras on tubes inserted in the body to directly visualize lymphoma in areas like the gastrointestinal tract.

Blood Work to Monitor Lymphoma

While a standard complete blood count cannot definitively diagnose lymphoma in most cases, blood tests are important for monitoring patients undergoing lymphoma treatment.

Doctors frequently order blood work during chemotherapy, radiation, immunotherapy, or other treatments to evaluate their effect and watch for side effects.

Complete Blood Count

Complete blood counts are closely tracked to monitor effects of lymphoma treatments on different cells:

• - White blood cells - Chemotherapy kills both cancer and healthy immune cells, so the count is followed to watch for lows that increase infection risk.
• - Red blood cells - Counts may drop, causing chemotherapy-induced anemia.
• - Platelets - Platelet counts can decrease, leading to clotting issues.

Lymphoma Markers

Certain proteins called tumor markers are sometimes elevated in lymphoma patients. Doctors may follow levels of markers like LDH, beta-2 microglobulin, and others during treatment to assess response.

Kidney and Liver Function

Chemotherapy agents are processed through the kidneys and liver. Blood tests monitoring function of these organs helps adjust dosing to prevent toxicity side effects.

Electrolyte Levels

Chemotherapy can deplete important electrolytes like potassium, magnesium, and sodium. Blood tests identify any electrolyte imbalances so they can be corrected.

Can Blood Tests Provide False Negatives?

Blood tests like complete blood counts are not always reliable for conclusively diagnosing lymphoma. Sometimes lymphoma will not cause abnormalities in the results.

Reasons lymphoma may not show up include:

• - Early stage disease - Blood counts can still be normal.
• - Hodgkin lymphoma - Often does not impact blood cell levels.
• - Normal WBC count - Even if clonal lymphocytes are present.

Even when blood work is normal, doctors will investigate other symptoms and use imaging and tissue biopsies to confirm or rule out lymphoma.

Takeaway Points

Key points to understand regarding lymphoma diagnosis and blood work:

• - Blood tests alone usually cannot definitively diagnose lymphoma but are done first.
• - Lymph node biopsies are required to confirm the diagnosis and type of lymphoma.
• - Once diagnosed, blood work helps monitor patients during lymphoma treatment.
• - Normal blood counts do not rule out a lymphoma diagnosis - further testing is pursued.
• - Discuss all symptoms thoroughly with your doctor and ask about recommended testing.

Blood tests provide pieces of the puzzle, but tissue biopsies, imaging, and a full clinical picture are needed for accurate lymphoma diagnosis and personalized treatment planning.

Frequently Asked Questions

What blood tests indicate lymphoma?

There is no one specific blood test that definitively diagnoses lymphoma. Doctors look for combinations of abnormalities in complete blood counts, tumor markers, kidney and liver function that may indicate lymphoma along with other testing.

Can a PET scan miss lymphoma?

PET scans are very helpful but can miss areas of lymphoma in some cases. PET scans may have false negatives if disease is localized in a small area, there is low-volume disease, or non-FDG-avid forms of lymphoma.

Can you have lymphoma with normal blood work?

Yes, it is possible to have lymphoma even with normal complete blood count results. Early stages of lymphoma often do not affect overall blood cell counts. Other testing like biopsies are needed to diagnose lymphoma.

What are the first signs of lymphoma?

Some early signs of lymphoma include swollen lymph nodes in the neck, underarms or groin, unexplained weight loss, drenching night sweats, persistent fatigue, fever, and itching. A painless lump is a very common early symptom.

Can a CBC detect cancer?

A CBC blood test can sometimes provide clues pointing to cancer, but cannot definitively diagnose it in most cases. Cancer can still be present even if a CBC is normal. Further testing with imaging, biopsies, or specialty blood tests is required.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.