Diarrhea and Gastroenteritis ICD-10-CM codes

Diarrhea documented as a symptom with no cause is R19.7. When the provider diagnoses gastroenteritis, enteritis, or colitis without stating that it is infectious, the code is K52.9 (noninfective gastroenteritis and colitis, unspecified), which includes colitis NOS and gastroenteritis NOS. K52.9 carries an Excludes1 note for R19.7, so do not report the symptom code with it.

Infectious gastroenteritis is coded in chapter 1: A09 for infectious gastroenteritis and colitis NOS, A08.4 for viral intestinal infection NOS (stomach flu), and organism-specific codes such as A04.72 for Clostridium difficile. When a stool study identifies the organism, use the specific A code rather than K52.9.

The specific K52 codes include K52.1 toxic gastroenteritis and colitis (which covers drug-induced diarrhea; code first a T51 to T65 toxic agent or add an adverse effect code), K52.21 food protein-induced enterocolitis syndrome, K52.3 indeterminate colitis, K52.831 collagenous colitis, K52.832 lymphocytic colitis, and K52.89 other specified noninfective colitis. Functional diarrhea is K59.1 and IBS with diarrhea is K58.0.

Dehydration (E86.0) is coded in addition when documented, and when a patient is admitted for dehydration due to gastroenteritis the reason for admission determines sequencing. Do not assign K52.9 for a positive stool culture that the provider has not linked to a diagnosis.