Flow cytometry is a powerful technique which allows us to look at the properties of individual cells and is most commonly used for evaluating peripheral blood, bone marrow, and other body fluids, often detecting tens of thousands of cells per minute. There are three major components to a flow cytometer; the fluidics which transports the sample to the flow cell, the optics which provides the excitation source and collect light signals and the electronics which converts optical signals into electrical signals then into digitized data.
Cells within patient samples are stained with antibodies against ‘CD markers’ on the surface, or inside the cell. These antibodies are conjugated to fluorescent tags which are detected by the flow cytometer. The pattern of CD markers is well documented for both normal cells and malignant populations.
Our test repertoire includes over 80 antibodies, covering around 50 CD markers. We have a range of panels designed to assist in the diagnosis of lymphoproliferative disorders, acute leukaemias, plasma cell dyscrasia, chronic myelomonocytic leukaemia, T cell disorders and a screening tube mainly used in myelodysplastic syndrome investigation. These panels are designed and validated in house by our team of scientists, in accordance with national and international guidance.
At NEHODS we review any liquid or tissue sample that may contain a haematological malignancy. Cytological assessment involves reviewing liquid samples such as blood, bone marrow aspirate material, cerebrospinal fluid, ascitic fluid and pleural fluid. After processing and staining, reviewing the liquid using a microscope allows the team to look at the cells that are present and note any morphological abnormalities or abnormal infiltration. Histological assessment involves reviewing solid tissue samples – mainly lymph node and bone marrow trephine but can include review of a sample from any part of the body that may be infiltrated by haematological malignancy such as skin, bowel, spleen and lung. After processing and staining, reviewing the thin sections using a microscope allows the team to look at the structure of the material as well as the cellular content. Morphological examination of liquid and solid material is supplemented special stains and by techniques such as flow cytometry and immunohistochemistry which allows us to determine if an abnormal population of cells is present and the pattern of antigen expression. Bone marrow trephines are reviewed and reported by haematologists and lymph node biopsies are reported by histopathologists.