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The History of PSA

PSA was first identified in human seminal fluid in 1970 by American researcher Richard Ablin, who recognized the protein's potential forensic value for identifying semen in criminal investigations, long before anyone imagined it would eventually become one of medicine's most widely used and controversial cancer screening tests. American biochemist T. Ming Chu and his colleagues later purified PSA directly from prostate tissue in 1979 and subsequently developed the first reliable blood test capable of measuring it, paving the way for PSA's widespread adoption as a prostate cancer screening tool throughout the 1980s and 1990s. In a genuinely notable historical twist, Ablin himself later became one of PSA screening's most outspoken public critics, arguing for decades that the test's poor ability to distinguish aggressive cancer from harmless, slow-growing disease had led to considerable unnecessary treatment for men across the country and beyond.

What PSA Actually Is

PSA, or prostate-specific antigen, is a protein produced almost exclusively by cells within the prostate gland, normally functioning to liquefy semen after ejaculation, helping sperm move more freely and effectively toward their intended destination. Small amounts of PSA normally leak into the bloodstream from healthy prostate tissue, but this amount can rise considerably higher whenever the prostate becomes enlarged, inflamed, or affected by cancer, since all three conditions can disrupt the normal architecture that otherwise keeps PSA largely confined within the gland itself. Because benign prostate enlargement and prostatitis can elevate PSA just as easily as cancer can, an elevated result alone never definitively confirms cancer, requiring further, considerably more specific testing to properly distinguish between these very different possible underlying causes at play.

How PSA Is Measured

PSA is measured from a standard blood sample using automated immunoassay platforms, in which antibodies bind specifically to PSA molecules, generating a measurable signal directly proportional to its actual concentration present in the sample tested that day. Because recent ejaculation, vigorous exercise, prostate examination, and certain medical procedures can all temporarily elevate PSA, doctors generally recommend avoiding these specific activities for at least twenty-four to forty-eight hours before a scheduled blood draw. When PSA results fall into an ambiguous, borderline range, doctors may also order a free PSA test, which measures what percentage of total PSA circulates unbound, since a lower free percentage more strongly suggests cancer over benign disease.

Scientists Behind the Science

Richard Ablin's original 1970 discovery of PSA gave medicine its first genuine glimpse of this now-famous protein, though he himself could never have anticipated the test's eventual explosive growth or the intense controversy that would later surround its widespread clinical use. T. Ming Chu's subsequent development of a practical, reliable blood test throughout the late 1970s transformed Ablin's basic scientific discovery into the single most widely ordered cancer screening test for men worldwide, fundamentally reshaping prostate cancer detection for decades afterward. Together, their combined contributions, and Ablin's later outspoken criticism of his own discovery's clinical application, illustrate the genuinely complicated, evolving relationship between scientific discovery and real-world medical practice.