Hospitals that have published their previously confidential prices to comply with a new federal rule have also blocked that information from web searches with special coding embedded on their websites, according to a Wall Street Journal examination.

The information must be disclosed under a federal rule aimed at making the $1 trillion sector more consumer friendly. But hundreds of hospitals embedded code in their websites that prevented Alphabet Inc.’s Google and other search engines from displaying pages with the price lists, according to the Journal examination of more than 3,100 sites.

The code keeps pages from appearing in searches, such as those related to a hospital’s name and prices, computer-science experts said. The prices are often accessible other ways, such as through links that can require clicking through multiple layers of pages.

“It’s technically there, but good luck finding it,” said Chirag Shah, an associate professor at the University of Washington who studies human interactions with computers. “It’s one thing not to optimize your site for searchability, it’s another thing to tag it so it can’t be searched. It’s a clear indication of intentionality.”

Among websites where the Journal found the blocking code were those for some of the biggest U.S. healthcare systems and some of the largest hospitals in cities including New York and Philadelphia. They include hospitals owned by HCA Healthcare Inc., Universal Health Services Inc., the University of Pennsylvania Health System and NYU Langone Health. Some regional systems also had such code on their websites, including Michigan’s Beaumont Health and Novant Health in Winston-Salem, N.C.