Historic Update to ICD-10 Endometriosis Diagnosis Codes

With ever-increasing medical knowledge, the classification of diseases is important to provide a common language for reporting and monitoring. This is where the International Classification of Diseases (ICD) comes in. The World Health Organization (WHO) and 10 international centers create, maintain, and revise the ICD. The latest version, ICD-10, contains important updates regarding endometriosis.

How have ICD codes evolved over time?

Coding for medical conditions has existed since the 19th century. The International Statistical Institute adopted the first “International List of Causes of Death” in 1893. The sixth edition of this list was published in 1948. The WHO adopted this in the form of ICD coding.

The WHO released ICD-7 in 1957, ICD-8 in 1968, and ICD-9 in 1979. The U.S. modified ICD-9 into its own version and created ICD-9-CM (clinical modification). The introduction of ICD-9-CM was revolutionary because it enhanced the scope and utility of these codes by incorporating additional information such as surgical procedures. ICM-9-CM was available in three volumes: the first two volumes contained diagnosis codes while the third included inpatient procedures.

However, with the fast pace of medical advancements, ICD-9-CM soon started becoming inadequate. The WHO started working on ICD-10 even before ICD-9 was complete. ICD-10 was published in 1990 with more than 155,000 codes.

Based on input from the National Center for Health Statistics (NCHS), the U.S. created ICD-10-CM. This includes the creation of diagnosis-symptom combinations to reduce the number of codes, information about managed care, and ambulatory encounters, and greater specificity. NCHS updates ICD-10-CM each year.

In the U.S., ICD-10 is in two forms. ICD-10-CM for all healthcare settings and ICD-10-PCS (procedure coding system) for inpatient settings only.

The latest ICD revision is ICD-11. The 72nd World Health Assembly adopted this in 2019, which came into effect on January 1, 2022.

What is the use of ICD coding?

ICD codes are important in collecting mortality data and enabling clinicians, healthcare providers, and financial providers to make evidence-based decisions. Coding helps compare health statistics across WHO member countries in a standardized manner. All WHO member countries must use the most current ICD version for reporting disease and death statistics.

As mandated by the U.S. Department of Health and Human Services (HHS), all Health Insurance Portability and Accountability Act (HIPAA)-covered entities must follow the most up to date ICD codes.

What were the traditional endometriosis codes in ICD-10-CM?

Despite affecting up to 1 in 10 women of reproductive age, doctors still don’t understand endometriosis well. They therefore often misdiagnose the disease as symptoms overlap with those of other diseases of the abdomen and pelvic region. Moreover, noninvasive diagnoses are often not conclusive.

There were no ICD codes for endometriosis for over 40 years. Since the 1970s, all endometriosis diagnoses were under the ICD-10 code N80.9 – “Endometriosis, unspecified”. Similarly, all endometriosis surgery appeared under the Current Procedural Terminology (CPT) code 58662 – “laparoscopy, surgical; with fulguration or excision of lesions of the ovary, pelvic viscera, or peritoneal surface by any method“. We currently know there are many stages and manifestations of this disease that include bladder, bowel, and thoracic endometriosis, among others. These codes put severe limits on the manner in which various manifestations of the disease are detailed and treated. It ultimately created disparities in diagnosis and posed challenges in providing appropriate health coverage.

More importantly, the previous ICD-10 endometriosis coding did not validate the myriad of debilitating endometriosis symptoms that patients experience and the work that clinicians and researchers have dedicated their time to.

Who was behind the initiative to update ICD-10-CM endometriosis codes?

Dr. Ted T. M. Lee is currently the Director of Minimally Invasive Gynecologic Surgery at the University of Pittsburgh Medical Center at Magee Women’s Hospital and President of the American Association of Gynecologic Laparoscopists (AAGL). In 2016, the AAGL commissioned him to liaison with the American College of Obstetricians and Gynecologists (ACOG) Coding Committee to understand and improve the coding problem for endometriosis.

Dr. Lee made a presentation to the Centers for Disease Control and Prevention (CDC) in 2020. Here, he detailed various aspects of endometriosis and the need to revise the ICD-10-CM coding for the disease. He and his colleagues went on to develop 100 new codes for endometriosis. These codes serve to represent the various multi-organ manifestations of the disease. They also lay the foundation for future procedure code changes.

What is the new ICD-10-CM update for endometriosis?

The new ICD-10-CM coding continues to group endometriosis under N80. However, this now includes codes from N80.0 to N80.5 that cover endometriosis of the uterus (N80.0), ovaries (N80.1), fallopian tubes (N80.2), pelvic peritoneum (N80.3), rectovaginal septum and vagina (N80.4), and intestines (N80.5).

The new ICD-10-CM update also provides codes for various pelvic and extra-pelvic endometriosis forms. These include bladder and ureters (N80.A), cardiothoracic space (N80.B), abdomen (N80.C), pelvic nerves (N80.D), and endometriosis at other sites (N80.8). A unique case study of isthmocele endometriosis, which Dr. Tamer Seckin recently presented also gets a mention under N85.A.

Each section offers many sub-section codes that further detail the diagnosis. For example, N80.3 denotes endometriosis of the pelvic peritoneum. Under this, the N80.31 sub-section indicates endometriosis of the anterior cul-de-sac.

N80.31 further includes:

• N80.311: superficial endometriosis of the anterior cul-de-sac
• N80.312: deep endometriosis of the anterior cul-de-sac
• N80.319: endometriosis of the anterior cul-de-sac, unspecified depth, endometriosis of the anterior cul-de-sac NOS

Responses to these new changes to ICD-10-CM have been overwhelmingly positive.

Dr. Tamer Seckin said,

“We’re thrilled about this long overdue but monumental step forward to legitimize the complex, multi-organ nature of endometriosis surgery. This will open doors for the patient community, improving patient treatment and providing critical data for research advancements. A great thank you to Dr. Lee and everyone else who worked on this”.

The inclusion of 100 new endometriosis codes into ICD-10-CM is a historical step that lays the foundation for further changes in endometriosis CPT surgical codes and corresponding billing systems, thus giving proper validation and legitimacy to both patients and healthcare providers.

 Please do not hesitate to share your thought about this historic event below our post on Facebook or Instagram.