CPT® code 92537 describes a bithermal caloric vestibular test, which requires a total of four irrigations (one warm and one cool in each of the two ears). The scenario specifies that only three irrigations were performed. Because the service described by the code was not fully completed, it is considered a reduced service. Modifier -52 (Reduced Services) is appended to indicate this reduction. The code descriptor for 92537 already includes the term "bilateral," making the use of modifier -50 (Bilateral Procedure) redundant and incorrect.

B. 92537-50-52: This is incorrect because CPT® 92537 is inherently a bilateral procedure, as stated in its description. Appending modifier -50 is inappropriate.

C. 92538-50: This is incorrect as 92538 represents a monothermal test (two irrigations), not the three performed. Modifier -50 is also inappropriate for this bilateral code.

D. 92537-50: This is incorrect because it implies the full service of four irrigations was completed, which contradicts the scenario. Modifier -50 is also incorrectly applied.

1. American Medical Association. (2023). CPT® 2024 Professional Edition.

Code 92537 Description: "Caloric vestibular test with recording

bilateral; bithermal (ie

one warm and one cool irrigation in each ear)." This description confirms the procedure is bilateral and requires four irrigations.

Appendix A

Modifier -52: "Reduced Services: Under certain circumstances a service or procedure is partially reduced or eliminated at the physician's or other qualified health care professional's discretion. Under these circumstances the service provided can be identified by its usual procedure number and the addition of the modifier 52

signifying that the service is reduced." This guideline directly applies to the scenario where only three of the four required irrigations were performed.

Appendix A

Modifier -50: "Bilateral Procedure: ... Note: This modifier should not be appended to a CPT code that has a bilateral description..." This note explicitly prohibits the use of modifier -50 with codes like 92537.

2. AAPC. (2023). 2024 CPC Exam Study Guide. Chapter 11: Medicine.

The section on Vestibular Function Tests explains that 92537 represents the complete bithermal test (four irrigations). It further clarifies that if a procedure is not performed in its entirety as described by the CPT® code

modifier -52 should be used to report the reduced service.