This bill, known as "Heidi's Law," mandates the inclusion of methadone in federal workplace drug testing programs and for transportation employees. The Secretary of Health and Human Services (HHS) is directed to revise the Mandatory Guidelines for Federal Workplace Drug Testing Programs within 90 days of enactment, specifically expanding the opiate category to include methadone. Upon completion, HHS must publish a final notice of this revision in the Federal Register. Following HHS's revision, the Secretary of Transportation (DOT) must issue regulations within 60 days to incorporate methadone testing into drug-testing panels for transportation employees. Furthermore, the bill requires HHS to conduct an annual review of the Mandatory Guidelines to identify and include any other new drugs that should be tested. Consistent with these annual updates, DOT is also mandated to revise its regulations to include testing for these newly established substances in transportation employee drug tests.