Medical Coding for Digestive Disorders in ICD-10-CM

ICD-10 for Digestive DisordersThe ICD-9 medical coding system categorizes individual digestive diseases inadequately due to imprecision and non-specificity. This leads to frequent misdiagnoses. The codes should clearly specify the epidemiology and impact of digestive diseases. The ICD-10 coding introduced a few changes that provide the highest level of specificity for reporting, to ensure more accurate diagnosis and correct reimbursement. Here are the major ICD-10 coding changes related to digestive disorders.


The ICD-10 categories for ulcers including gastric ulcer, duodenal ulcer, peptic ulcer, site unspecified and gastrojejunal ulcer are very similar to the corresponding categories in the ICD-9 coding system. The codes are classified into acute, chronic, unspecified as acute or chronic (applies only to ulcers without complication), and with and without hemorrhage and/or perforation in both coding systems. The difference is with the use of fifth digit with ulcer codes. If ICD-9 uses an additional fifth digit to specify whether the ulcer occurs with or without obstruction, ICD-10 does not require a fifth digit as this system no longer considers obstruction as an axis of coding for gastrointestinal ulcers. Examples are:

ICD-9 ICD-10
531.00: Acute gastric ulcer with hemorrhage, without mention of obstruction K25.0: Acute gastric ulcer with hemorrhage
531.01: Acute gastric ulcer with hemorrhage, with obstruction K25.0: Acute gastric ulcer with hemorrhage


K56.60: Unspecified intestinal obstruction (This is used as a separate code other than the ulcer code, K25.0)

Gastritis and Duodenitis

If the fifth digit of gastritis and duodenitis codes denote with and without hemorrhage in ICD-9, it specifies with and without bleeding in ICD-10.

ICD-9 ICD-10
535.00: Acute gastritis, without mention of hemorrhage K29.00: Acute gastritis without bleeding
535.01: Acute gastritis, with hemorrhage K29.01: Acute gastritis with bleeding  

In ICD-9, there are subcategories for gastric mucosal hypertrophy and eosinophilic gastritis, and one combined subcategory only for unspecified gastritis and gastro­duodenitis. ICD-9 has no provision for chronic superficial types. However, ICD-10 has provision for chronic superficial types. In the new coding system, gastric mucosal hypertrophy is coded to other gastritis, and eosinophilic gastritis is coded (K52.81, eosinophilic gastritis or gastroenteritis) under the section for non-infective enteritis and colitis. The subcategories for particular types of gastritis and duodenitis in ICD-10 are:

  • K29.0: Acute gastritis
  • K29.2: Alcoholic gastritis
  • K29.3: Chronic superficial gastritis
  • K29.4: Chronic atrophic gastritis
  • K29.5: Unspecified chronic gastritis
  • K29.6: Other gastritis
  • K29.7: Gastritis, unspecified
  • K29.8: Duodenitis
  • K29.9: Gastroduodenitis, unspecified

Ulcerative Colitis

The codes for ulcerative colitis have been greatly expanded in ICD-10. Ulcerative colitis codes are combination codes in ICD-10 that specify the type of colitis along with its associated complication. For example, there was only one code for left sided colitis (556.5) in ICD-9. The ICD-10 codes for this condition are:

  • K51.50: Left sided colitis, without complications
  • K51.51: Left sided colitis with complications
  • K51.511: Left sided colitis with rectal bleeding
  • K51.512: Left sided colitis with intestinal obstruction
  • K51.513: Left sided colitis with fistula
  • K51.514: Left sided colitis with abscess
  • K51.518: Left sided colitis with other complication
  • K51.519: Left sided colitis with unspecified complications

If there are separate subcategories for ulcerative (chronic) enterocolitis (556.0), ulcerative (chronic) ileocolitis (556.1), and universal ulcerative (chronic) colitis in ICD-9, these are specified under a single subcategory (K51.0, ulcerative (chronic) pancolitis) in ICD-10. There is a change in terminology for certain subcategories in ICD-10 as well. Pseudopolyposis of colon (556.4) is specified as inflammatory polyps of colon (K51.4) and ulcerative (chronic) proctosigmoiditis (556.3) is specified as ulcerative (chronic) rectosigmoiditis (K51.3).

Depending on the condition, you should use the codes appropriately and use additional codes, if necessary. If a chemical, medication or drug is listed as the causative agent for esophageal or stomach ulcer, you should sequence the code that specifies the agent before the code that is used to classify the ulcer. When the polyps are categorized as neoplasms, use an exclusion note related to category K51.4. This will direct the medical coder to use D12 (Benign neoplasm of colon, rectum, anus and anal canal).