Is ICD-10-CM code A04 billable?

No, A04 (Other bacterial intestinal infections) 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 A04 belong to?

A04 belongs to Chapter 1 of the ICD-10-CM tabular list: A00–B99 (Certain Infectious and Parasitic Diseases).

A04Not billable, use a more specific code below

Other bacterial intestinal infections

In Intestinal infectious diseases (A00-A09), chapter 1: Certain Infectious and Parasitic Diseases

11 billable codes under A04: all are a CC; none map to an HCC.A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment.

Instructional notes

Excludes1: not coded here, use a different code

bacterial foodborne intoxications, NEC (A05.-)
tuberculous enteritis (A18.32)

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.

Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.

Human Immunodeficiency Virus (HIV) Infections (page 19)
Infectious agents as the cause of diseases classified to other chapters (page 22)
Infections resistant to antibiotics (page 22)
Sepsis, Severe Sepsis, and Septic Shock (page 23)
Methicillin Resistant Staphylococcus aureus (MRSA) Conditions (page 27)
Zika virus infections (page 28)
Coronavirus infections (page 28)

Read Section I.C.1 (page 19)

All codes under A04

A04 can't be used on a claim. Pick a billable code below; grey headings group them.

A04 MS-DRGs

As the principal diagnosis, all 11 billable codes under A04 group to MS-DRG 371, 372, or 373 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to A04

Notes on these codes point to A04.

M49 Code First: enterobacterial infections (A01-A04)

About the condition

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

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

Gastroenteritis

Gastroenteritis is an inflammation of the lining of the stomach and intestines. The main symptoms include vomiting and diarrhea. It is usually not serious in healthy people, but it can sometimes lead to dehydration or cause severe symptoms.

Code history

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