The Office of the National Coordinator for Health IT has received 299 complaints of information blocking since it banned the practice in April.
The ONC prohibited information blocking, which occurs when healthcare organizations fail to share patients' information, because it hinders providers' ability to provide effective and prompt care.
The ONC's breakdown, posted Feb. 28, showed most complaints (211) were filed against healthcare providers, followed by health IT developers (46).
"ONC acknowledges each portal submission we receive and informs the claimant when we’ve shared their claim with OIG," the office said in a statement. "We also provide feedback, where applicable, to let people know if the information in their claim, on its face and as presented, appears to have no potential to involve conduct implicating the regulatory definition of information blocking."