Final answer:
Insurance companies may deny prescriptions if there's a wrong NDC number, an invalid patient's ID, or if it's a compounded drug with a legend drug. However, expired prescription coverage does not result in a denial but rather indicates that the patient no longer has active coverage.
Step-by-step explanation:
When it comes to understanding why a prescription may be denied by an insurance company, there are several reasons that this can occur, and not all involve insurance policy details.
An insurance company will deny a prescription for the following reasons: if it contains a compounded drug with at least one ingredient being a legend drug, if there is a wrong NDC number associated with the prescription, or if the patient's ID number is invalid.
However, if the prescription coverage has expired, this would not typically result in a denial, but rather a lack of coverage altogether; thus, the patient would need to resolve their insurance status.
It's important for both the pharmacist and the patient to ensure all details are correct to prevent any issues with prescription fulfillment.