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ICD-10-CM tabular list

A00-A09Intestinal infectious diseases

ICD-10-CM codes A00-A09 cover intestinal infectious diseases, within certain infectious and parasitic diseases. The block holds 94 codes across 10 categories, of which 79 are billable and 15 are header codes that cannot be submitted on a claim.

Risk adjustment in A00-A09

0 codes in this block map to a CMS-HCC, which means the diagnosis carries a risk-adjustment payment when it is documented and coded. Under-coding here is money left on the table; over-coding here is what audits are for.

  • HCC 92 Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
  • HCC 2 Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock
  • HCC 6 Opportunistic Infections
  • HCC 283 Empyema, Lung Abscess

What else to watch in A00-A09

  • 71 codes are named in Medicare coverage policies. An LCD or NCD lists them as supporting medical necessity, or explicitly as not supporting it. Which applies depends on the MAC for your state.

Categories in A00-A09

ICD-10-CMFY2026-Apr· effective April 1, 2026