Blood analyzers vary in terms of the functions they include. The basic functions are the measurement of erythrocyte sedimentation rates (ESRs) and coagulation tests. They are often referred to as haemotology analyzers.
Electrical Impedance Cell Counters
By passing an electrical current across a small opening when cells in a dilute solution of blood pass through, changes in electrical impedance can be automatically detected by the analyzer. The blood sample is treated with a lytic agent to dissolve the red blood cells, so only white blood cells and platelets are counted. White blood cells create noticeably bigger impedance spikes than the platelets.
Optical Detection Cell Counters
This technology provides additional information on blood cells when used in conjunction with electrical impedance cell counting techniques and is increasingly being incorporated into the modern blood analyser. A laser beam is directed at a narrow flow of blood solution in a capillary tube; as cells pass through the beam, they produce different degrees of transmission, reflectance and scattering of light. Advanced software analyses these patterns and yields a numerical distribution of the different types of cell.
Blood Analyzers with Reticulocyte Counts
This feature drastically cuts the time spent on manual reticulocyte counting. A solution of blood cells is treated with a supravital dye, which differentially stains red blood cells containing reticulin (reticulocytes). Manually viewing the blood analyser slide prepared with the film of stained cells enables fast and simple counting of the reticulocytes.
Blood Analyzers with Coagulometers
These perform automated tests on blood samples to assess clotting ability. Typical tests include prothrombin times, partial thromboplastin times, D dimer assays, factor assays and Lupus anticoagulant screens. Optical technology monitors the process of clotting by recording changes over time to the level of a specific wavelength’s absorption.
Blood Analyzers with Blood Gas Evaluation
This is a new feature that additionally permits the analysis of up to 19 blood gas parameters.