Federal officials are taking steps to clarify new requirements surrounding Medicaid coverage of autism treatments.

Over the summer, the Centers for Medicare and Medicaid Services issued a bulletin to states indicating that Medicaid programs across the country must provide “medically necessary diagnostic and treatment services” to beneficiaries with autism under age 21.

Now, the agency is providing new details about the mandate.

In a frequently asked questions document released this week, CMS emphasized that the directive does not specifically require state Medicaid programs to cover applied behavior analysis. Rather, that is one of several offerings that states can choose to provide in order to fulfill their obligations to those on the spectrum.

“CMS is not endorsing or requiring any particular treatment modality for ASD. State Medicaid agencies are responsible for determining what services are medically necessary for eligible individuals,” federal officials indicated.

Already at least one state has acted in response to this summer’s bulletin. California officials said earlier this month that they would begin covering ABA and other services for young people on the spectrum.

Medicaid officials indicated it could take time, however, for all states to review their current offerings and institute any necessary changes. At this point, CMS said there is “no specific time frame” to review compliance with the new directive.

“CMS believes states should complete this work expeditiously and should not delay or deny provision of medically necessary services,” the agency said.