A facility presents an ABN to a patient in the emergency room who is considered critical after a medical screening exam. The service performed may be noncovered by Medicare based on the diagnosis. The patient signs the ABN. The patient is stabilized and is placed in observation care for 48 hours and then sent home. Medicare denies the service based on frequency limits. Which of the following is most correct?
a. Facility may not bill the patient because two witnesses did not sign the ABN.
b. Facility may not bill the patient because the ABN is defective.
c. Facility may bill the patient for the services because the patient has had the service more frequently than Medicare considers necessary.
d. Facility may bill the patient for the services because the ABN was signed.