Is ICD-10-CM code K59 billable?

No, K59 (Other functional intestinal disorders) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code K59 belong to?

K59 belongs to Chapter 11 of the ICD-10-CM tabular list: K00–K95 (Diseases of the Digestive System).

K59Not billable, use a more specific code below

Other functional intestinal disorders

In Other diseases of intestines (K55-K64), chapter 11: Diseases of the Digestive System

14 billable codes under K59: 3 are a CC; 1 map to HCC 78 (Intestinal Obstruction/Perforation).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Excludes1: not coded here, use a different code

change in bowel habit NOS (R19.4)
intestinal malabsorption (K90.-)
psychogenic intestinal disorders (F45.8)

Excludes2: not included here, code separately if applicable

functional disorders of stomach (K31.-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

There are no chapter-specific rules for Chapter 11 yet, so the general rules in Section I.B apply.

Read Section I.C.11 (page 58)

All codes under K59

K59 can't be used on a claim. Pick a billable code below; grey headings group them.

K59 MS-DRGs

As the principal diagnosis, the billable codes under K59 group to MS-DRG 391, 392, 393, 394, or 395 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 391 Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC (12 of 14 codes)
DRG 392 Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC (12 of 14 codes)
DRG 393 Other Digestive System Diagnoses with MCC (2 of 14 codes)
DRG 394 Other Digestive System Diagnoses with CC (2 of 14 codes)
DRG 395 Other Digestive System Diagnoses without CC/MCC (2 of 14 codes)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Digestive Diseases

When you eat, your body breaks food down to a form it can use to build and nourish cells and provide energy. This process is called digestion. Your digestive system is a series of hollow organs joined in a long, twisting tube. It runs from your mouth to your anus and includes your esophagus, stomach, and small and large intestines. Your liver, gallbladder and pancreas are also involved. They produce juices to help digestion.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.