US No Surprises Act (42 USC 300gg-111 to 300gg-139) and 45 CFR Part 149 300gg-115(a)(3),(b): Answer network-status enquiries within 1 business day in writing, keep the answer 2 years, and honour in-network cost sharing where the enrollee relied on wrong directory information

When an enrollee asks by telephone, electronically or online whether a provider or facility is in network, the plan or issuer must respond as soon as practicable and within 1 business day by written electronic or print communication as the enrollee chooses, and keep that communication in the enrollee's file for at least 2 years. Where an enrollee received an item or service from a nonparticipating provider or facility after being told by the directory or the response protocol that it was participating, the plan must apply no more than in-network cost sharing and must count it toward the in-network deductible and out-of-pocket maximum.