PSA stands for prostate specific antigen which are produced by normal and cancerous prostate cells.
"We soon discovered my PSA was a bit higher than we thought it should be. I guess like a lot of old men, I had a few difficulties peeing and getting up in the middle of the night.
"Then one fateful night when I was away in Taupo, I had a little bit too much alcohol and I couldn't pee and I got carted off to hospital."
His prostate had been constricting his urethra but test results came back negative for cancer.
He continued with annual PSA checks with the levels slowly rising every year. The biopsy he had in 2010 came back positive.
In November 2010, he had his prostate removed with robotic prostatectomy, his gleason score came back at seven.
He has suffered from erectile and incontinence problems but is thankful he is alive today.
"If you don't pick it up, it can have disastrous consequences. It's so easy to just have a blood test."
Mr Calver said prostate cancer had the ability to spread very quickly, hence the need for the annual checks.
"We really encourage men just to check the PSA box when they are getting their blood tests. It's simple and then it is done."
Prostate cancer kills 600 men in New Zealand each year.
Graeme Woodside, Prostate Cancer Foundation chief executive, said too many men were dying when a simple test could save lives.
"Enough is enough. In 2016 it's time for Kiwi men to take more responsibility for their prostate health, starting from the time they turn 40, especially if there is family history of this disease.