The ICD-10-CM Manual contains official guidelines for coding and reporting, including coding conventions, general coding guidelines, and chapter-specific guidelines. These conventions and guidelines are rules and instructions that must be followed to classify and assign the most appropriate code. Understanding these conventions and guidelines are key to reaching the most appropriate code assignment.

• Conventions: A set of rules for use of the classification independent of the general or chapter-specific guidelines. Coding conventions and instructions of the classification take precedence over guidelines. (e.g., Code First).
• General guidelines: A set of rules and sequencing instructions for using the Tabular List and Alphabetic Index. These guidelines provide rules such as how to locate a code and obtain level of detail.
• Chapter-specific guidelines: A set of rules for specific diagnoses and conditions in a particular classification.

As with ICD-9, adherence to these guidelines is required under the Health Insurance Portability and Accountability Act (HIPAA).

Coding convention ? Code First

Some conditions have an underlying etiology and a manifestation due to the underlying etiology. In such cases, ICD-10 coding convention requires the underlying or causal condition be sequenced first, if applicable, followed by the manifested condition. This is referred to as the "Code First" coding convention. When this combination exists, there is a ?use additional code? note at the etiology code and a ?code first? note at the manifestation code. These instructional notes dictate the proper sequencing of the code: etiology followed by manifestation.

Guideline update: Please note the Official Guidelines for Coding and Reporting for fiscal year 2017 released an update to the Code First convention to include ?if applicable.?

Coding scenarios

Code the following scenarios per the ICD-10 Code First convention. Identify the etiology code and the manifestation code.

Susan is excited about her pregnancy. She is not concerned about overeating and jokingly says ?I?m eating for two.? At her regular OB visit during her second trimester, Susan complained of various symptoms. The OB noted in her records that Susan was severely obese and having pregnancy complications due to overeating. Susan?s OB suggested she cut back on calories and eat a healthier diet.

John presents to the office for his regular follow-up appointment since he?s been diagnosed with Pachydermoperiostosis (primary hypertropic osteoarthropathy). During his physical examination, John expressed concerns with some changes in his fingers and nails. He described recently noticing fingernail abnormalities and drumstick like clubbing of both hands. The doctor explained to John that nail abnormalities and digital clubbing is a common manifestation of Pachydermoperiostosis.

Jane went to the emergency room after experiencing days of severe abdominal pain, nausea, vomiting, and diarrhea. Numerous tests were done, and it was determined that Jane should be admitted to the hospital and treated for toxic gastroenteritis due to high levels of mercury. The origin of the mercury is documented as unknown. However, Jane suspects it came from dental fillings replaced several years ago.

Stay tuned

Throughout 2017, we will continue to communicate ICD-10-specific information through this article series to review some of the ICD-10 diagnosis code changes. We encourage you to keep up with the latest news and information by visiting the ICD-10 section of our website.