Doctors often begin a Hodgkin's lymphoma diagnosis by performing a physical examination of a person's lymph nodes, notes Mayo Clinic. If there is cause for concern, the next steps are to analyze blood tests and obtain images with X-rays, computerized tomography scans and positron emission tomography scans.
According to Mayo Clinic, doctors may also choose to surgically remove all or a portion of a swollen lymph node and send it to a lab for testing. If cancer is found, it may be necessary to perform a bone marrow biopsy to see if the cancer has spread to the bones.
The American Cancer Society explains that diagnosing non-Hodgkin's lymphoma follows much the same process. If a swollen gland is found during a physical examination, a doctor may send a patient home with antibiotics to rule out the possibility of a simple infection. If this does not shrink the lymph node in question, the next step is to perform a biopsy of the area. This can be done through surgery or by inserting a needle into the lymph node to extract cells for lab testing, notes the American Cancer Society.
Similar to Hodgkin's lymphoma, a non-Hodgkin's cancer diagnosis is likely to prompt the need for a bone marrow biopsy, because the disease infects the white blood cells. Rarely, a doctor may also perform a spinal tap to determine whether the cancer has spread to the brain, according to the American Cancer Society.