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ICD-10-CM 2027

ICD-10 code for Colibacillosis

A49.8

Other bacterial infections of unspecified site

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Colibacillosis”. Page updated September 29, 2026.

About coding Colibacillosis

The ICD-10-CM code for Colibacillosis is A49.8 (Other bacterial infections of unspecified site). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A49.8.

Within A49, choose A49.8 (Other bacterial infections of unspecified site) only when documentation doesn't support a more specific option: staphylococcal infection, unspecified site (A49.0), streptococcal infection, unspecified site (A49.1), hemophilus influenzae infection, unspecified site (A49.2), mycoplasma infection, unspecified site (A49.3) and bacterial infection, unspecified (A49.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 867 (Other Infectious and Parasitic Diseases Diagnoses with MCC, relative weight 2.1859), DRG 868 (Other Infectious and Parasitic Diseases Diagnoses with CC, relative weight 1.0235) and DRG 869 (Other Infectious and Parasitic Diseases Diagnoses without CC/MCC, relative weight 0.6787), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

More specific Colibacillosis codes (official index)

  • as the cause of other disease B96.20 — Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewhere
  • generalized A41.51 — Sepsis due to Escherichia coli [E. coli]

Common questions about Colibacillosis ICD-10 codes

What is the ICD-10 code for Colibacillosis?

A49.8 — Other bacterial infections of unspecified site. More specific codes apply when the documentation supports them: B96.20, A41.51.

What is the ICD-10 code for generalized colibacillosis?

A41.51 — Sepsis due to Escherichia coli [E. coli].

Is A49.8 billable?

Yes. A49.8 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can A49.8 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict A49.8 as a principal diagnosis.

Is A49.8 a CC or MCC?

No. A49.8 is neither a CC nor an MCC under MS-DRG v44.0.