Your child support Order will provide a percentage that the other party is obligated to pay for your child's uncovered medical expenses after exceeding the $357 per child per year (2013 Child Support Formula Supplement).  Under MCL 552.511a you only have 28 days from the time insurance denies coverage or you are billed for uncovered medical expenses to submit request for payment to the other party for their share.  You have six months to ask the Friend of the Court to enforce or 1 year from the date of service where there was insurance coverage.