Inventor of the Week Archive

Browse for a different Invention or Inventor

ROSALYN S. YALOW
Radioimmunoassay (RIA)

In 1959, Rosalyn Sussman Yalow co-invented what is still one of the most significant methods of chemical analysis used in medicine: "radioimmunoassay" of human blood and tissue.

Yalow was born in 1921 in New York City. She began reading before she entered kindergarten, and her first favorite subject was mathematics. A high school teacher taught her love of chemistry; and at Hunter College, two professors and guest lecturer Enrico Fermi convinced her to major in physics, in which she earned a BS in 1941.

That same year, Yalow was rescued from a future as a mere secretary to scientists by the University of Chicago, which offered her a graduate student position and teaching assistantship. She was the only woman out of 400 members of the College of Engineering faculty, and encountered the usual chauvinism: she was told by her first Chemisty professor, for example, that her A- grade "confirms that women do not do well at laboratory work." But Yalow persevered, even while World War II increased the teaching load and the students' stress level, completing her dissertation in 1945.

Yalow returned to New York, where she taught physics to WWII veterans at Hunter College. In time, she also secured a research position at the Bronx Veterans Administration Hospital (1947). Yalow's graduate work had been in the development and use of apparatus for measuring radioactive substances; now, she helped equip and run the VA Hospital's Radioisotope Service --- one of the first such in the country --- often inventing equipment for the new discipline as she went along.

After committing to the VA full-time in 1950, Yalow began a 22-year partnership with Dr. Solomon A. Berson. Their first joint efforts were in the use of radioisotopes to analyze blood for evidence of thyroid and other diseases, and to observe the distribution of globin and serum proteins. They later expanded their methods to include the observation of hormones, especially insulin.

Over the years, Yalow and Berson developed a system by which they would tag a known sample of a hormone with a radio-isotope, then mix a blood sample of unknown content with a complex of that tagged hormone and its antibody. Because the antibodies regularly abandon the tagged hormones for any "naturally occuring" hormones of the same sort, the amount of "stranded" radioactive hormones in the final mixture reflects precisely the amount of the same hormones occurring in the sample being tested.

This was radioimmunoassay (RIA), a revolutionary diagnostic process that was largely ignored when Yalow and Berson published it in 1959. Their primary use then for the process was to study diabetes. But over time, their expanded applications and their promotion of the method resulted in the scientific community's rush to embrace RIA. Today, there are myriad applications of RIA in use.

For example, pediatricians can use a single drop of a baby's blood, in a process that costs less than $1, to detect and cure one type of mental retardation; pediatricians also use the process to detect and counter growth hormone disorders. Blood banks use RIA to screen blood efficiently. Researchers use RIA to study diseases as varied as high blood pressure and infertility, and to test nutritional regimens. Clinics use RIA to detect illicit drug use. In short, when Yalow accepted the Nobel Prize in Medicine for inventing RIA (1977), on behalf of herself and Berson, who had died five years earlier, the Committee called RIA the most valuable advance made in basic clinical research in the previous two decades.

Yalow and Berson could almost certainly have patented the RIA process. If they had, the patent would inevitably have made them millionaires. Instead, to their credit, they made extraordinary efforts to get RIA into common use, because they put its potential value to humankind ahead of its potential value to themselves.

Rosalyn Yalow has been honored many times for this ethos of service, as well as her scientific talents: for example, she was the first woman to win the Lasker Award for Basic Medical Research (1976); and recently, Yalow was inducted into the Women in Technology International Hall of Fame (1997). She has continued to conduct and supervise research in the same VA lab (now named for Berson), and to teach, as Berson Distinguished Service Professor, at the Mount Sinai School of Medicine, now an affiliate of the Bronx VA hospital.