An 18-year-old man's pregnancy test came back positive. The result saved his life.

In 2014, then 18-year-old Byron Geldard was suffering from a persistent pain in his side that doctors initially dismissed as a gym injury. But when scans revealed a tumor that had spread to his lungs, he was diagnosed with cancer. The problem? Doctors weren't sure what type it was, per The Telegraph.

It was then that specialists at the Teenage Cancer Trust unit in Cambridge, UK, made a bizarre suggestion: he should take a home pregnancy test, per The Daily Mail.

“I could have had four or five different types,” Geldard recalled. Though confused, he gave it a shot. The result was shocking. “There I was with a positive pregnancy test and something growing inside of me,” he remarked. “I thought I was going to end up in a documentary.”

Hands hold a positive pregnancy testCanva

The Science Explained

The strange request was based on sound medical science. Home pregnancy tests work by detecting a hormone called beta-human chorionic gonadotropin (hCG), which is produced by the placenta during pregnancy. As it turns out, some testicular tumors also produce hCG.

Doctors look over scansCanva

“The pregnancy hormone (HCG) is often (but not always) produced by testicular tumors,” explained Dr. Danish Mazhar, a consultant at Cambridge University Hospitals, per KPRC. He noted that the hormone level can be used for both diagnosis and for monitoring the cancer's spread.

The positive test gave doctors their answer: Geldard had stage 4 testicular cancer. The diagnosis allowed them to begin targeted chemotherapy immediately. The strange parallels didn't stop there. “Throughout my cycles of chemo, the hospital would monitor the ‘pregnancy hormone’ through blood tests,” the teenager said. “When I was about to go into surgery, I had to have an epidural like a pregnant woman; it was all very weird.”

Surgeons with a patient on the operating tableCanva

From Patient to Advocate

After months of rigorous treatment, Geldard was declared cancer-free. He went on to become an ambassador for The Teenage Cancer Trust, using his incredible story to raise awareness.

While the diagnostic trick is not new—a spokesperson noted it had been used for years—it remains relatively unknown to the public. Geldard’s story serves as a powerful and unforgettable example of the surprising ways medicine can work. “It took me a while to realize what was happening to me,” he said of the whirlwind experience. But that one strange test made all the difference.

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This article originally appeared earlier this year.