56-year-old female is postmenopausal with abnormal vaginal bleeding.

1. Procedure and CPT® Code Selection:

The procedure performed was a hysteroscopy to examine the uterine cavity due to abnormal vaginal bleeding. This is a diagnostic hysteroscopy.

CPT® Code 58555 is specifically for a diagnostic hysteroscopy to examine the uterine cavity, which aligns with the procedure performed in this case.

2. Rationale for Excluding Other Options:

Code 58558 is for a hysteroscopy with a surgical procedure, such as biopsy or removal of a lesion or polyp, which was not performed in this case.

Code 58579 is an unlisted procedure code for the female genital system and is unnecessary here because there is a specific code (58555) for diagnostic hysteroscopy.

Code 58578 is also an unlisted hysteroscopic procedure code and is not appropriate when a specific diagnostic code exists.

3. AAPC and CPT® Coding Guidelines:

AAPC guidelines indicate that 58555 should be used for diagnostic hysteroscopy procedures without any surgical intervention.

Therefore, the correct answer, following CPT® guidelines, is C. 58555.