Then he said to call a doctor.
A quick Internet search told Gibb the abnormal levels of hormones in his blood were most often found in pregnant women, steroid users and men with testicular cancer. A biopsy soon confirmed what he had already concluded. The doping ban was subsequently lifted, but Gibb was expected to miss the Olympics anyway while recovering.
"The Olympics were out," he said in a video posted to his website in the days leading up to the London Games. "It was a tough dream to let go of. The toughest part was telling people and letting them know. Because once it came out of my mouth, it felt real."
But surgery got the cancer — all of it, meaning Gibb didn't need chemotherapy. He got back on tour with partner Sean Rosenthal and earned enough points to qualify for the London Games in the very last event of the year.
Now, Gibb is a two-time Olympian.
And a two-time cancer survivor.
"The pinnacle of our sport is the Olympic games. For me to go and put USA on my chest, it means the world to me. It's something so special," said Gibb, who has a scar on his left shoulder from a 2004 skin cancer. "It almost wasn't a reality to me. I was scared. I didn't know anything about it, didn't know how to react."
Gibb and Rosenthal, who finished fifth in Beijing, won their first match in the 2012 Games but lost their second on Monday night against Poland. Asked in London about all that has transpired since the 2008 Olympics, Gibb politely referred a reporter to his website and declined to discuss it.
"It's too emotional," he said, his voice cracking. "The facts are out there and you can find what you need. But if I start talking to you, I'm going to start breaking down."
Rosenthal also said he didn't want to revisit the details.
"It was tough at first, but he's such a strong guy," he said. "He was working as hard as anybody."
According to spokesman Hans Stolfus, whose agency represents Gibb and helped produce the video at jakegibb.com, Gibb was told by USADA in December 2010 that he had abnormal levels of alpha fetoprotein and beta-hCG in his blood and he would be suspended for doping. (Beta-hCG, or human chorionic gonadotropin, is often taken by steroid users to combat testicular shrinkage that is a side effect of the performance-enhancing drugs.)
Before the tester hung up, he told Gibb to go see a doctor immediately — but he would not say why, Stolfus said. Gibb's Internet search found a lot of references to AFP and beta-hCG for pregnant women but only one explanation in men: testicular cancer.
"USADA actually saved his life," Stolfus told The Associated Press.
Surgery was scheduled.
Then, the day before he was to have his testicle removed he learned that his wife, Jane, was pregnant.
"Going through cancer and having my wife pregnant and giving birth while I was on tour, pursuing this Olympic dream, it felt like a heavy load on my shoulders. It was a very tough year," Gibb said in the video. "I realized what matters most to me, and that's health and family."
It wasn't just Gibb's Olympics at risk: It may have been too late for Rosenthal to find a quality partner and accumulate enough points to make it to London.
In a statement provided by Stolfus, Rosenthal stressed the most important thing was Gibb's health but added it was a relief to have his old partner back in time for an Olympic run — even though Gibb had to take it slow for about a month to avoid tearing open his scar.
"We really got to put volleyball in perspective after something like that. Volleyball is just a game," Rosenthal said. "Jake is one of my best friends. He's like a brother, and I wouldn't be here without him. To get through something like that and turn around and play like he has is crazy. But I'm glad I'm on his team, 'cause as far I'm concerned, he can beat anything."
Ten days after the surgery, tests showed Gibb was healthy enough to avoid chemotherapy. His wife, Jane, gave birth to their son Crosby about 11 months ago.
"I don't know how you go through something like this without someone right there with you," he said as the video showed images of him and his wife in their kitchen.
"The birth of my son, it was a game-changer. It was more impactful than I would have thought. I don't know what I would have thought before, but it's amazing what he has become in my world: everything. He's an amazing little boy. He's learning to crawl and learning to walk. I love him to pieces."
He and Rosenthal went back onto the international tour, where points for the Olympic rankings are accumulated, and slowly moved up the rankings before passing Nick Lucena and Matt Fuerbringer on the final weekend of qualifying for the second and final spot available to the Americans.
"Finding out that I didn't have to go through chemotherapy was the biggest relief and joy of my life to that point. It opened up my world," Gibb said. "It opened up the Olympics again, it opened up a career — just to keep competing. I feel like I'm the luckiest guy in the world to have my family and friends around me and to play the game I love."
AP Sports Writer Anne Peterson contributed to this story.