ICD-10 Code for Bacterial Infection in the Stomach
The ICD-10 code for bacterial infection in the stomach is K29.70 (Gastritis, unspecified, without bleeding) when the specific bacterial etiology is unknown, or A04.9 (Bacterial intestinal infection, unspecified) for acute bacterial gastroenteritis. For Helicobacter pylori infection specifically, use B96.81 (Helicobacter pylori as the cause of diseases classified elsewhere) as a secondary code with K29.70.
Primary Coding Options
- K29.70 - This code represents gastritis without bleeding and is the most appropriate when bacterial infection causes gastric inflammation 1
- A04.9 - Use this for acute bacterial gastroenteritis when the infection involves the stomach with diarrheal symptoms 1
- K65.0 - For acute peritonitis secondary to gastric perforation with bacterial infection 1
Specific Bacterial Etiology Codes
When the causative organism is identified, add a secondary code:
- B96.81 - Helicobacter pylori (the most common bacterial stomach infection) 2, 3
- A02.0 - Salmonella gastroenteritis 1
- A04.5 - Campylobacter enteritis 1
- A03.9 - Shigella infection, unspecified 1
Clinical Context Matters
For complicated intra-abdominal infections involving the stomach, use K65.0 (acute peritonitis) as the primary code 1. The guidelines specify that infections from stomach and proximal jejunum perforations require specific coding based on whether source control was achieved within 24 hours 1.
- If gastric perforation with bacterial peritonitis: K65.0 (primary) + specific organism code (secondary) 1
- If gastric malignancy with infection: C16.9 (primary) + K29.70 (secondary) + organism code 1
- If healthcare-associated gastric infection: Add Y95 (nosocomial condition) 1
Important Coding Considerations
The ICD-10 system contains over 141,000 codes with significant complexity 4. For gastric bacterial infections, the key is distinguishing between:
- Uncomplicated gastritis (K29.70) - inflammation without perforation or abscess 1
- Complicated infection (K65.0) - perforation, abscess, or peritonitis requiring source control 1
- Specific pathogen identification - always add organism-specific B96.xx or A0x.x codes when known 1, 5
Common Pitfalls to Avoid
- Do not use K29.70 alone if the bacterial organism is identified - always add the secondary organism code 5
- Avoid using A04.9 for H. pylori gastritis - this organism has its own specific code (B96.81) and causes chronic rather than acute infection 2, 3
- Do not code gastric perforation as simple gastritis - perforations require K65.0 for peritonitis 1
- Remember timing matters - acute stomach perforations with source control within 24 hours may be coded differently than delayed presentations 1
The ICD-10-CM algorithm for bacterial infections has approximately 80% positive predictive value when properly applied in clinical databases 5.