Lemelson-MIT Program
Who We Are Awards Outreach News
Invention Dimension Search Site Map Contact Us
Inventor of the Week

Inventor of the Week Archive

Browse for a different Invention or Inventor


WALLACE H. COULTER (1913-1998)

Automated Blood Analysis

Coulter In the basement of his home, Wallace H. Coulter conceived a principle, then invented a device, that revolutionized the analysis of microscopic particles in fluids, most notably blood.

Coulter was born in Little Rock, Arkansas in 1913. His favorite childhood activity was tinkering with electrical devices and crystal radio sets. He studied electrical engineering at the Georgia Institute of Technology, but left before graduating. In the years leading up to and during World War II, Coulter worked in radio and for General Electric and Raytheon.

After the War, Coulter supplanted his day jobs by experimenting, along with his younger brother, Joseph, an electrical engineer, in the basement of their Chicago home. In 1947, Coulter had his first major breakthrough. He devised a theory by which electrical charge could be used to determine the size and number of a given type of microscopic particle in a fluid. By 1949, Coulter had invented a machine that put this theory, the Coulter Principle, into practice.

The Coulter Counter, patented in 1953, works basically as follows. The solution being studied is drawn with a vacuum pump through an electrically charged tube with a tiny hole at one end. As it passes through the hole, each particle within the solution blocks the electrical field for a moment. The force and frequency of the distortions in voltage can be matched to specific types and numbers of particles.

The Coulter Counter transformed hematology. The Model A, first marketed in 1953, automatically and accurately reported white and red blood cell counts in ten minutes. The standard then was for technicians to spend at least half an hour counting the cells of a blood sample through a microscope. Hospitals and biotechnicians around the world were understandably eager to obtain the Coulter Counter.

The brothers began production immediately, and later incorporated as Coulter Electronics, Inc. (1958). They moved their headquarters to Hialeah, Florida in 1961. Joseph directed the business, while Wallace refined his invention. He soon expanded the types of particles and solutions the device could analyze; and over time he improved the speed and versatility with which results were printed out.

As the company expanded, becoming Coulter Corporation, its mainstay continued to be devices for the Complete Blood Count (CBC) analysis, familiar from hospital-centered television shows. Still, Coulter Counters are routinely used to determine the contents of various fluids, including paint, glass, ceramics, and even foods like chocolate. Even after his basic patents expired in the early 1970s, Coulter's continuing innovations kept his company at the forefront of the industry that he had created. For example, he pioneered research in diagnosing cancer by analyzing monoclonal antibodies, and in "flow cytometry," the identification of cells by their passage through a laser.

In the mid-1990s, Coulter Corp. --- still a family-owned business --- had annual sales of about $750 million, to about 30,000 customers world-wide. Today, perhaps 90% of the automated blood counters in use are genuine or knock-off Coulter Counters. Notwithstanding the deaths of Joseph (1995) and Wallace (1998), and the company's acquisition in 1997 by Beckman Instruments, Inc., Coulter products continue the brothers' tradition of "Science Serving Humanity" with great commercial success.

[Aug. 2000]

Invention Dimension
Inventor of the Week Inventor of the Week
Inventor's Handbook Inventor's Handbook
Games & Trivia Games & Trivia
Links & Resources Links & Resources