Endometriosis ICD-10-CM codes

Category N80 was rebuilt in FY2022 to code endometriosis by anatomic site, depth and side. The 4th character is the organ: 0 uterus (N80.03 for adenomyosis), 1 ovary, 2 fallopian tube, 3 pelvic peritoneum, 4 rectovaginal septum and vagina, 5 intestine, 6 cutaneous scar, 8 other, 9 unspecified, plus letters A (bladder and ureters), B (cardiothoracic space), C (abdomen) and D (pelvic nerves). Most sites take a 5th character for depth (superficial versus deep) and a 6th for laterality. An endometrioma of the right ovary of unspecified depth is N80.101; deep endometriosis of the left ovary is N80.122.

Endometriosis usually involves more than one site, and each documented site gets its own code. There is no combination code for multiple sites; N80.9 (endometriosis, unspecified) is reserved for a documented diagnosis with no site stated, which is common before laparoscopic confirmation. Superficial versus deep should be taken from the operative report or imaging; when neither is documented, use the unspecified depth code for that site rather than N80.9.

Related diagnoses are reported in addition: N94.5 secondary dysmenorrhea or N94.6 dysmenorrhea unspecified when documented as a separate problem, and N97.1 or N97.9 for infertility attributed to endometriosis. Chronic pelvic pain attributed entirely to endometriosis is not coded separately. Adenomyosis (N80.03) is an N80 code even though it is sometimes described as a uterine rather than endometriotic condition.