CPT 73221 covers Magnetic Resonance Imaging (MRI) of any joint in the upper extremity (shoulder, elbow, or wrist) without contrast.
Laterality Modifiers (RT and LT)
Because humans have two shoulders, two elbows, and two wrists, Medicare requires you to specify which side was scanned. You MUST append Modifier RT (Right) or LT (Left) to 73221. Missing this modifier is a guaranteed denial.
Joint vs Non-Joint Codes
Ensure you are using the correct code. 73221 is for joints. If you are scanning the long bones (e.g., the humerus or forearm) rather than the joint itself, you must use the non-joint MRI code (73218).
NCCI Edits
If billing for both the right and left shoulders on the same day, you must bill it on two lines (e.g., 73221-RT and 73221-LT) or use Modifier 50 depending on your MAC's specific formatting preference.