The use of flow cytometry in the clinical laboratory has grown substantially in the past decade. This is attributable in part to the development of smaller, user-friendly, less-expensive instruments, and a continuous increase in the number of clinical applications. Flow cytometry measures multiple characteristics of individual particles flowing in a single file in a stream of fluid. Light scattering at different angles can distinguish differences in size and internal complexity, whereas light emitted from fluorescently labeled antibodies can identify a wide array of cell surface and cytoplasmic antigens. This approach makes flow cytometry a powerful tool for detailed analysis of complex populations in a short period of time. This report reviews the general principles in flow cytometry and selected applications of flow cytometry in the clinical hematology laboratory.
Flow cytometry provides rapid analysis of multiple characteristics of single cells. The information obtained is both qualitative and quantitative. Whereas in the past flow cytometers were found only in larger academic centers, advances in technology now make it possible for community hospitals to use this methodology. Contemporary flow cytometers are much smaller, less expensive, more user-friendly, and well suited for high-volume operations. Flow cytometry is used for immunophenotyping of a variety of specimens, including whole blood, bone marrow, serous cavity fluids, cerebrospinal fluid, urine, and solid tissues. Characteristics that can be measured include cell size, cytoplasmic complexity, DNA or RNA content, and a wide range of membrane-bound and intracellular proteins. This review will describe the basic principles of flow cytometry and provide an overview of some applications to hematology.
In Mindray BC 6800, SF Cube is a path-breaking technology for reliable blood cell analysis, including WBC differential, reticulocytes, and NRBC with efficient flagging. The 3-D scattergram builds the power to better identify and differentiate blood cell populations, especially to reveal abnormal cell population undetected by other techniques.
Except the routine 5-part WBC differential results, BC-6800 can also give the results for atypical lymphocyte and blast, immature cells. Additionally, flags for band, NRBC, lyse-resistant red cell, turbidity, PLT clump, etc., are also available.
IMG (#,%) provides information about the presence of immature granulocytes, if any, including promyelocytes, myelocytes, metamyelocytes, immature eoisnophils, and immature basophils. BC 6800 has four dedicated counting channels for WBC measurement to prevent interference caused by the presence of lipid particles, lyse-resistant RBCs, PLT clumps, and NRBCs. This increases the reliability of WBC data. Basophils are counted in a dedicated channel that detects information about the cell volume and cellular complexity. This provides more accurate and reliable basophil results.
Additional to this, RBC analysis with SF Cube technology helps differentiation of reticulocytes from mature red cells by their reaction with fluorescent stain. Besides the conventional parameters such as RET# and RET%, BC 6800 also provides additional data concerning immature reticulocytes (IRF), which assist in early diagnosis of anemia and monitoring the bone marrow response to therapy.
So smaller, less expensive instruments and an increasing number of clinically useful parameters are creating more opportunities for routine clinical laboratories to use flow cytometry/cytometers in the diagnosis and management of diseases.