Intestinal infectious diseases
ICD-10 Codes (90)
A01A01.0A01.00A01.01A01.02A01.03A01.04A01.05A01.09A01.1A01.2A01.3A01.4A02A02.0A02.1A02.2A02.20A02.21A02.22A02.23A02.24A02.25A02.29A02.8A02.9A03A03.0A03.1A03.2A03.3A03.8A03.9A04A04.0A04.1A04.2A04.3A04.4A04.5A04.6A04.7A04.71A04.72A04.8A04.9A05A05.0A05.1A05.2A05.3A05.4A05.5A05.8A05.9A06A06.0A06.1A06.2A06.3A06.4A06.5A06.6A06.7A06.8A06.81A06.82A06.89A06.9A07A07.0A07.1A07.2A07.3A07.4A07.8A07.9A08A08.0A08.1A08.11A08.19A08.2A08.3A08.31A08.32A08.39A08.4A08.8A09Updates & Changes
FY 2026 Updates
New Codes (2)
Revised Codes (2)
Deleted Codes
No codes deleted in this range for FY 2026
Historical Changes
- •FY 2025: Updated terminology from "Clostridium difficile" to "Clostridioides difficile"
- •FY 2024: Added specificity codes for viral gastroenteritis types
- •FY 2023: Enhanced documentation requirements for foodborne illness reporting
Upcoming Changes
- •Proposed addition of codes for emerging enteric pathogens in FY 2027
- •Under consideration: New codes for antibiotic-associated diarrhea not due to C. difficile
Implementation Guidance
- •Review all FY 2026 updates for A00-A09 codes before implementation
- •Always verify the most current codes in the ICD-10-CM manual
- •Ensure clinical documentation supports the selected diagnosis codes
- +3 more guidance items...
Range Overview
The A00-A09 code range encompasses intestinal infectious diseases that are classified within the ICD-10 system. This range is primarily used when documenting specific conditions that fall into this category and require precise medical coding for billing, statistics, and clinical documentation purposes. These codes cover various gastrointestinal infections caused by bacteria, viruses, parasites, and other microorganisms that affect the digestive system.
Key Usage Points:
- •Use when specific intestinal infectious diseases within A00-A09 range are diagnosed
- •Requires thorough clinical documentation of symptoms and causative organism
- •Common in gastroenterology, infectious disease, and primary care specialties
- •May require additional specificity codes for organism identification
- •Important for accurate billing and epidemiological statistics
Coding Guidelines
When to Use:
- ✓Patient presents with confirmed intestinal infectious disease
- ✓Diagnostic workup identifies specific causative organism
- ✓Clinical documentation supports gastrointestinal infection diagnosis
- ✓Symptoms include diarrhea, vomiting, abdominal pain with infectious etiology
When NOT to Use:
- ✗Non-infectious gastrointestinal disorders (use K00-K95 range)
- ✗Food poisoning without confirmed infectious agent (use T61-T62)
- ✗Symptoms only without confirmed infectious diagnosis
- ✗Chronic gastrointestinal conditions of non-infectious origin
Code Exclusions
Always verify that the patient's condition doesn't fall under these more specific categories before using codes from this range.
Documentation Requirements
Proper documentation for intestinal infectious diseases requires detailed clinical information to support accurate code selection and justify medical necessity for treatment and diagnostic procedures.
Clinical Information:
- •Specific infectious organism identification (when known)
- •Clinical presentation and symptom onset
- •Severity of illness and complications
- •Diagnostic test results and laboratory findings
- •Treatment response and clinical course
- •Source of infection (when identifiable)
Supporting Evidence:
- •Laboratory culture results and sensitivity testing
- •Stool analysis and microscopy findings
- •Blood work including CBC with differential
- •Imaging studies if complications suspected
- •Contact tracing and epidemiological factors
- •Travel history and exposure documentation
Good Documentation Example:
Patient presents with acute onset watery diarrhea, fever 101.5°F, and abdominal cramping for 48 hours. Stool culture positive for Salmonella enteritidis. Recent travel to Mexico 5 days prior to symptom onset. CBC shows mild leukocytosis. Patient responding well to supportive care and ciprofloxacin therapy.
Poor Documentation Example:
Patient has diarrhea and stomach ache. Stool positive for bacteria. Given antibiotics.
Common Documentation Errors:
- ⚠Failure to specify the causative organism when laboratory results are available
- ⚠Insufficient documentation of symptom severity and clinical impact
- ⚠Missing travel history or exposure information
- ⚠Inadequate documentation of diagnostic workup performed
- ⚠Lack of treatment response documentation
- ⚠Failure to document complications or associated conditions
Range Statistics
Coding Complexity
Specialty Focus
These codes are predominantly used across multiple medical specialties, with varying documentation requirements and clinical contexts.
Primary Specialties:
Clinical Scenarios:
- • Acute gastroenteritis with confirmed bacterial pathogen
- • Food-borne illness outbreak investigation
- • Travel-related diarrheal illness
- • Healthcare-associated intestinal infections
- • Chronic diarrhea workup with infectious etiology
Resources & References
Essential resources and references for accurate coding and clinical management of intestinal infectious diseases, including official guidelines and educational materials.
Official Guidelines:
Clinical References:
Frequently Asked Questions
How do I code intestinal infections when the specific organism is unknown?
When the specific organism is not identified, use the most specific code available based on clinical presentation. For example, use A09 (Diarrhoea and gastroenteritis of presumed infectious origin) for infectious gastroenteritis when no specific pathogen is identified. Always document the clinical reasoning and any diagnostic attempts made.
What's the difference between food poisoning and foodborne illness codes?
Food poisoning codes (A05) are used when there's a specific toxic effect from contaminated food, often with rapid onset. Foodborne illness codes may include various infectious agents transmitted through food. The key is identifying the specific organism and mechanism (infectious vs. toxic) when possible.
Should I code traveler's diarrhea with a specific organism code?
Yes, if the specific organism is identified (e.g., E. coli, Shigella), use the specific organism code. If no organism is identified but the clinical presentation and travel history suggest infectious gastroenteritis, use A09. Consider adding Z87.891 (Personal history of nicotine dependence) if relevant to the clinical picture.
How do I handle antibiotic-associated diarrhea vs. C. diff colitis?
Antibiotic-associated diarrhea without confirmed C. diff should be coded as K59.1 (Diarrhea, unspecified). If C. difficile is confirmed, use A04.7X codes for specific C. diff infections. The distinction is important for infection control and treatment decisions.
When should I use additional codes with intestinal infections?
Consider additional codes for: dehydration (E86.-), electrolyte imbalances (E87.-), complications like sepsis (A41.-), healthcare-associated conditions (Y95), or personal history codes (Z87.-) when relevant. These provide a more complete clinical picture.
What documentation is required for outbreak-related cases?
For outbreak cases, document: the outbreak connection, public health investigation involvement, common source exposure, attack rates if known, and any public health measures taken. This supports appropriate resource allocation and public health coding.
How do I code recurrent intestinal infections?
Code each episode based on the specific organism identified. For recurrent infections with the same organism, document whether it's a relapse, reinfection, or treatment failure. Consider underlying conditions that may predispose to recurrent infections and code them as additional diagnoses.
Are there special considerations for pediatric intestinal infections?
Pediatric cases may require additional attention to: hydration status, nutritional impact, growth effects, and family/daycare exposures. Document age-appropriate symptoms and use age-specific reference ranges for laboratory values. Consider codes for failure to thrive (R62.51) if applicable.