There are 70,000 ways to get sick, hurt or mortally injured, and the U.S. is making them official.

On Thursday, U.S. hospitals, doctors and other care providers have to start using internationally developed standards called ICD-10 codes to bill government programs and private insurers in the nation’s $2.9 trillion-a-year health-care system. The codes cover everything from parrot bites to getting sucked into a jet engine.

Doctors have already begun mocking the diagnostic list, picking out the most absurd and arcane, such as Z63.1, “Problems in relationship with in-laws,” or V91.07XA, “Burn due to water skis on fire.” Yet for health-care providers who have payments at stake, the complex change is no joke.

Health insurers and government programs stopped accepting the old set of codes, called ICD-9, in the early morning hours Thursday, completing the switch. In a study released last month, the Government Accountability Office, the investigative arm of Congress, said “little is known” about how much it will cost the health-care system to make the transition. HCA Holdings Inc., the Nashville, Tennessee-based hospital chain, said 2015 costs for the transition to the new codes will be about $30 million.

Insurers began preparing for ICD-10 in 2010 and have been ready since the government first delayed implementation in 2012, said Clare Krusing, a spokeswoman for America’s Health Insurance Plans, a Washington-based industry group. “Every deadline that has come up, we were ready.”

‘Smooth Transition’

Concerns about the changeover grew as the possibility loomed that Congress might not pass a spending bill and cause a shutdown of the federal government. The administration, which mandated adoption of the new codes, has said it’s ready, despite any political or technical challenges.

“We will pay claims and we’ll continue to implement the rollout,” said Patrick Conway, chief medical officer for the U.S. Centers for Medicare & Medicaid Services. “Our goal is to have a smooth transition.” Conway spoke during a conference call last week during which Obama administration health officials acknowledged industry anxiety about the changes.

Administration officials, who have already delayed the codes’ debut twice, say the system will help identify efficient ways to manage all kinds of conditions, from heart disease to roller-skating injuries. 

More Paperwork?

To doctors, it looks like more paperwork and, for at least a while, the possibility of slower payments.

“I think there could be a lot of delays in payments and a cash-flow crunch across medicine,” said Peter Masucci, a pediatrician in private practice in Everett, Massachusetts, just outside Boston. “That’s the biggest concern.”

Since having severe problems with reimbursement delays in the early 2000s, Masucci has worked to get payment times down to about three weeks. A new group of billing codes, almost five times as long as the existing one, might mean a return to long waits for payments from insurers, he said.

“Are the payers as ready as we are?” he said. “That’s what worries me. My staff have a bad habit of wanting to get paid every Thursday.”