The principle of hematology analyzer

All hematology analyzers are using Coulter Principle, let's take a look at what it is.

The Coulter Principle General Description

It is invented by Wallace Coulter, One of the giant corporate players in the field of medical technology grew from a fundamental invention Wallace Coulter made in his basement in 1948. The Coulter Principle provided a methodology for counting, measuring and evaluating microscopic particles suspended in fluid. His invention led to major breakthroughs in science, medicine and industry. This principle was the origin of Coulter's numerous inventions, which revolutionized healthcare and standardized quality control in industry. Medicine's most prescribed test, the Complete Bood Count, became routine, affordable, accurate and fast.

Wallace Coulter founded the Coulter Corporation with his brother Joseph, where they made significant advances in hematology, immunology, cytometry, cancer and infectious disease diagnostics and fine particles analysis.

Coulter Counter of Coulter Electronics Ltd. The Coulter Principle relies on the fact that particles moving in an electric field cause measurable disturbances in that field. The magnitudes of these disturbances are proportional to the size of the particles in the field. Coulter identified several requirements necessary for practical application of this phenomenon. First, the particles should be suspended in a conducting liquid. Second, the electrical field should be physically constricted so that the movement of particles in the field causes detectable changes in the current. Finally, the particles should be dilute enough so that only one at a time passes through the physical constriction, preventing an artifact known as coincidence.

Major applications
Hematology
The most successful and important application of the Coulter Principle is in the characterization of human blood cells. The technique has been used to diagnose a variety of diseases, and is the standard method for obtaining red blood cell counts (RBCs) and white blood cell counts (WBCs) as well as several other common parameters. When combined with other technologies such as fluorescence tagging and light scattering, the Coulter Principle can help produce a detailed profile of patients’ blood cells.

Cell count and size
In addition to clinical blood cells (~6-10 micrometres, typically), the Coulter principle has established itself as the most reliable laboratory method for counting a wide variety of cells, ranging from bacteria (< 1 micrometre in size), fat cells (~400 micrometre), plant cell aggregates (~>1200 micrometre), and stem cell embryoid bodies (~900 micrometre). The technique has become so standardized that ASTM International (formerly American Society for Testing and Materials) has published a procedure on the topic: ASTMF2149-01(2007) Standard Test Method for Automated Analyses of Cells-the Electrical Sensing Zone Method of Enumerating and Sizing Single Cell Suspensions.