Question: A recent report from our radiologist noted that she had performed a limited obstetrical ultrasound, using a transvaginal approach. Should this be coded with 76815 or 76830? Illinois Subscriber Answer: The correct answer depends on whether the transvaginal ultrasound (76830, Ultrasound, transvaginal) is performed in addition to a transabdominal study (76815, Ultrasound, pregnant uterus, B-scan and/or real time with image documentation; limited [fetal size, heart beat, placental location, fetal position, or emergency in delivery room]) or as an independent examination. If both are performed, both codes are reported. The fact that the examination was performed to monitor the pregnancy will be conveyed with the appropriate ICD-9 codes (e.g., V22.x, Normal pregnancy). 76815, on the other hand, more accurately describes the exam's limited scope, but it typically is reported only for a transabdominal approach. Therefore, based on the codes' most common uses and the accurate definitions CPT contains, you should use 76830.
Technically speaking, either one of these codes could be considered correct for the limited exam you describe, if performed alone. However, 76830 does a better job of describing the actual service (transvaginal approach). Because this code description does not differentiate between a limited and complete exam, it is not necessary to append modifier -52 (Reduced services) to the code.