In simple words: Modifier CA is used when a patient receives an emergency procedure in a hospital but passes away before they can be officially admitted.

HCPCS modifier CA is used to indicate that a procedure, designated as "inpatient-only" under the Outpatient Prospective Payment System (OPPS), was performed emergently on an outpatient who expired prior to being formally admitted as an inpatient. This modifier facilitates appropriate payment for services rendered in such circumstances.

Example 1: An outpatient presents to the emergency department with a life-threatening condition requiring an "inpatient-only" procedure. The procedure is performed, but the patient expires before being admitted. Modifier CA is appended to the procedure code., An individual arrives at the hospital in cardiac arrest. An emergency coronary artery bypass graft (CABG), an "inpatient-only" procedure, is attempted, but the patient dies before being admitted to the hospital. Modifier CA is applied., A patient with severe trauma requiring emergency surgery is brought to the hospital. The procedure is initiated, but the patient expires during the operation. Due to the patient's outpatient status and pre-admission expiration, modifier CA is appended.

Documentation should clearly support the medical necessity of the "inpatient-only" procedure performed on an emergency basis. The patient's outpatient status at the time of the procedure and the time of death prior to inpatient admission should be explicitly documented.The medical record must demonstrate that the death occurred before the patient could be formally admitted.

** Modifier CA triggers a specific outpatient payment through APC 5881 (previously APC 0375). Only one procedure per claim can carry this modifier.