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One reason for adopting ICD-10-CM that is cited frequently is the increased specificity provided by ICD-10 codes.

This increased specificity provides more precise language and up-to-date terminology, which in turn allows for a more accurate description of a patient’s disease or condition. More accurate diagnoses in turn provide improved morbidity data, making it easier to identify and track existing and new health threats. ICD-10-CM classification of foodborne illnesses provides one example of the more precise language and terminology used to describe diseases and conditions.

Foodborne illnesses commonly are referred to as food poisoning. The term “food poisoning” generally refers to any illness resulting from a foodborne pathogen that causes intestinal symptoms such as nausea, vomiting and diarrhea. The term also groups illnesses by symptoms rather than by the pathogen that causes the illness (such as a toxin, bacterium, virus or parasite). While laypeople still refer to illnesses caused by food as food poisoning, public health departments recognize and classify food poisoning as occurring either due to an infection (bacterium, virus, parasite or other microorganism) or due to a toxin. The terms used are “foodborne infection” and “foodborne intoxication.”

This terminology change can be identified clearly when the alphabetic indexes in ICD-9-CM and ICD-10-CM are compared. If the term “intoxication, food” is referenced in ICD-9-CM, the coder is instructed to see ”poisoning, food.” If the same term is referenced in ICD-10-CM, foodborne toxins are listed. Because food intoxication and food poisoning still are used interchangeably, referencing the term “poisoning, food” in ICD-10-CM still will yield codes for foodborne illnesses caused by both toxins and infections. It is also possible to find the correct code in ICD-10-CM by referencing “enteritis, infectious,” or by searching for “infection” followed by the specific microorganism (such as, infection, Shigella).

Intestinal Infectious Diseases

Intestinal infectious diseases (A00-A09) make up the first block of codes in Chapter 1. Intestinal infectious diseases may be caused by a microorganism itself, or by toxins produced by the microorganism. Generally, enteritis caused by the microorganism itself is classified as a foodborne infection, while enteritis caused by the toxin produced by the microorganism is classified as foodborne intoxication. One aspect that makes classification of intestinal infections difficult is that some enteric pathogens cause both types of enteritis; that is, the bacteria itself may cause enteritis, yet toxins produced by the same bacteria may exacerbate the condition.

Foodborne Infections

Categories A00-A04 report some of the more common foodborne intestinal infections caused by bacteria. Examples include:

  • A02.0 Salmonella enteritis
  • A03.0 Shigellosis due to Shigella dysenteriae
  • A04.0 Enteropathogenic Escherichia coli infection
  • A04.5 Campylobacter enteritis

Another cause of foodborne intestinal infections is parasites. These codes are found in categories A06-A07. Some of the more common intestinal parasitic diseases include:

  • A07.1 Giardiasis (lambliasis)
  • A07.2 Cryptosporidiosis
  • A07.4 Cyclosporiasis

Viral enteritis and gastroenteropathies are classified in category A08, Viral and other specified intestinal infections. Examples include:

  • A08.0 Rotaviral enteritis
  • A08.11 Acute gastroenteropathy due to Norwalk agent
  • A08.2 Adenoviral enteritis

Foodborne Intoxication

As the term “intoxication” suggests, foodborne intoxication is caused by toxins in food. Foodborne intoxications classified in Chapter 1 – Infectious and Parasitic Diseases result from toxins in bacteria or other organisms that are growing on food. Other sources of foodborne intoxication are heavy metals, chemicals or other substances that have become concentrated in food, such as mercury in shellfish. However, toxic effects of these substances are classified in Chapter 19 – Injury, Poisoning and Certain Other Consequences of External Causes. Category A05, Other bacterial foodborne intoxications, not elsewhere classified, contains codes for the more common infectious organisms that produce toxins responsible for the disease processes. Examples of foodborne intoxications include:

  • A05.0 Foodborne staphylococcal intoxication
  • A05.1 Botulism food poisoning
  • A05.2 Foodborne Clostridium perfringens (Clostridium welchii) intoxication


Foodborne illnesses represent just one example of new classifications and new terminology found in ICD-10-CM. Understanding the reasons for the introduction of new and revised classifications of some diseases and disease processes can help coders locate and assign the correct codes.

About the Author

Lauri Gray, RHIT, CPC, has worked in the health information management field for 30 years. She began her career as a health records supervisor in a multi-specialty clinic. Most recently she has worked as a clinical technical editor of coding and reimbursement print and electronic products. She has also taught medical coding at the College of Eastern Utah. Areas of expertise include: ICD-10-CM, ICD-10-PCS, ICD-9-CM diagnosis and procedure coding, physician coding and reimbursement, claims adjudication processes, third-party reimbursement, RBRVS and fee schedule development. She is a member of the American Academy of Professional Coders (AAPC) and the American Health Information Management Association (AHIMA).

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