DENVER - Porter Adventist Hospital is now expanding the date range that may have put surgery patients at risk for HIV and Hepatitis B and C.

The Colorado Department of Public Health and Environment said Friday patients who underwent orthopedic or spine surgery from July 21, 2016, until April 5 of this year should get a blood test to rule out infection.

Officials originally had said only patients who'd undergone surgery from July 2016 to February 20, 2018, should get tested. They updated that information Friday.

The hospital started sending letters out to those patients. 9NEWS spoke to one who said he just doesn't understand how this could happen.

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"I got this letter this afternoon in the mail," explained William Buckley. "As a long time attorney, I don't know if they're just trying to cover their tracks now in terms of liability."

Buckley served as Denver's Chief Deputy District Attorney for decades and said he knows a thing or two about paperwork. He underwent hip surgery at Porter Adventist last December.

"It just came as a total shock to me and I immediately started worrying," he said.

The hospital said surgical instruments weren't cleaned adequately - specifically a gap in the pre-cleaning process, prior to manual washing, machine washing, and sterilization.

"It doesn't make sense that it took them that long to discover the problem," Buckley said.

A problem the hospital said is low risk for patients. But for Bill that isn't enough.

"It sure is a compelling reason to get testing and further testing later on," he said. "I think they need to be honest with the public and let them know and to clean up their act."

In the letter, the hospital lists locations patients can get a free blood test.

Porter Adventist has stopped all surgeries and the Colorado Department of Public Health and Environment said disease control investigation is ongoing.

EDITOR’S NOTE: Previous reporting on this stated patients who had surgery from Feb. 20, 2016 to April 5, 2018, should get a blood test. The correct timeframe is July 21, 2016, to April 5, 2018.