How is non-Hodgkin lymphoma diagnosed, and are blood tests sufficient for diagnosis?

A blood test alone is not sufficient to diagnose non-Hodgkin lymphoma. Although blood tests play a complementary role in assessing a patient's general health and understanding the extent to which the disease affects body functions, they cannot definitively confirm the presence of cancerous lymphoma cells or precisely determine their type [1].

Why are blood tests not enough?

The process of diagnosing non-Hodgkin lymphoma requires precise procedures to identify and classify the affected cells, which blood tests alone cannot provide. Diagnosing this type of cancer relies primarily on examining tissue from the lymphatic system directly under a microscope [2]. Doctors use blood tests (such as a complete blood count or tumor marker tests) to gather information about immune system activity, assess liver and kidney function, or detect signs of inflammation or changes in protein levels; however, this information is insufficient to provide a final cancer diagnosis [1].

Approved diagnostic procedures

A comprehensive medical diagnosis for non-Hodgkin lymphoma involves a series of integrated steps that specialists follow to achieve high accuracy, including:

• Clinical examination: A thorough physical examination to look for abnormal swelling in the lymph nodes in the neck, armpits, or groin area [1].
• Biopsy: A biopsy is considered the decisive and essential step for diagnosing lymphoma. It involves taking a sample of the affected tissue or an entire lymph node for laboratory examination. This allows doctors to determine if the cells are cancerous and precisely identify their subtype, which is vital for choosing the appropriate treatment protocol [1].
• Medical imaging: A doctor may order a chest X-ray or other imaging scans to assess the extent of the spread of abnormal cells in the body [1].
• Additional tests: In some cases, bone marrow tests may be needed to assess the extent to which it has been affected by the disease [1].

Understanding the type and classification of the lymphoma helps determine whether the condition is "indolent" (slow-growing) or "aggressive" (fast-growing), which entirely changes the treatment plan [2]. You can read more about the nature of this condition in our article on Lymphoma: Types, Symptoms, and Latest Available Treatments (Arabic).

When should you consult a doctor?

If you notice persistent, painless swelling in the lymph nodes, or if you suffer from systemic symptoms such as severe night sweats, unexplained fever, or sudden weight loss for no apparent reason, you should see a doctor immediately to perform the necessary examinations [1]. Avoid delaying diagnosis or relying on self-diagnosis, as early medical intervention significantly contributes to improving treatment outcomes. Remember that some cases may not require immediate treatment and may undergo what is called "watchful waiting," based on an assessment of the case by specialists [1].

Medical references

• Lymphoma
• Non-Hodgkin Lymphoma Treatment (PDQ®)–Patient Version