Once the medical team has a suspicion of Hodgkin's Disease, if the lymph nodes don't feel normal when examined by a doctor, the doctor may need to extract a small piece of tissue and look at it under the microscope to see if there are any cancer cells. This is called a biopsy. The cells they look for are Reed-Sternberg cells, a cell specific to Hodgkin's Disease.

Hodgkin's is medically diagnosed by taking a tissue sample (biopsy) and searching for the presence of Reed-Sternberg cells, a cell specific to Hodgkin's Disease. A needle biopsy is sometimes used but a surgical biopsy, removal of a whole node, is preferred in getting enough tissue for a definite diagnosis.