The IHC BCL6 test is an immunohistochemistry (IHC) stain used in pathology to detect the presence of the BCL6 protein in tissue samples, most commonly lymph node or bone marrow biopsies.

BCL6 (B-cell lymphoma 6) is a nuclear transcription factor that plays an important role in the development and regulation of germinal center B-cells. It is normally expressed in germinal center cells but can also be involved in certain lymphomas.