ICD-10-CM Use Additional Code Notes · Chapter 1 · FY 2027 A00-B99

Use Additional Code Notes in Chapter 1: Certain infectious and parasitic diseases ICD-10-CM

A Use Additional Code note means a second code should be added, after this one, to fully describe the condition. In Chapter 1 (A00-B99), notes printed in the chapter name other codes 31 times, and Use Additional Code Notes anywhere in the Tabular List name the chapter’s codes 111 times, covering 23 distinct codes, categories and ranges. Switch views to read the list either way.

✓ From the official FY 2027 ICD-10-CM Tabular ListDefinitions follow the Official Guidelines, Section I.A
31
References in Its Notes
111
References to Its Codes
23
Chapter Codes Named
A00-B99
Chapter 1
Chapter 1

Use Additional Code Notes by the code that carries the note

7 of 7 shown
  • Chapter note Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
    • code to identify resistance to antimicrobial drugs (Z16.-)
  • Block note Block A15-A19 Tuberculosis applies to 51 codes
    • code, if applicable, for associated cachexia (E88.A)
  • A48.3 Toxic shock syndrome
    • code to identify the organism (B95, B96)
  • A81 Atypical virus infections of central nervous system applies to 10 codes
  • B18 Chronic viral hepatitis applies to 5 codes
    • code, if applicable, for ascites (R18.8)
  • B33.4 Hantavirus (cardio)-pulmonary syndrome [HPS] [HCPS]
    • code to identify any associated acute kidney failure (N17.9)
  • B39 Histoplasmosis applies to 7 codes
    • endocarditis (I39)
    • meningitis (G02)
    • pericarditis (I32)
    • retinitis (H32)

The first view lists notes printed in this chapter (a note on a category or block applies to every code beneath it). The second lists codes of this chapter named by Use Additional Code Notes anywhere in the Tabular List, including notes in other chapters.

Questions About Use Additional Code Notes

What does a Use Additional Code note mean?

A Use Additional Code note tells you to add a second code, reported after the code that carries the note, to describe the condition completely. In an etiology/manifestation pair it sits at the etiology code and points to the manifestation (Section I.A.13). The FY 2027 Tabular List has 1,491 of them; 1,174 name other codes, with 1,438 references to 389 distinct codes, categories and ranges.

Where does the additional code go?

After the code carrying the note. For etiology/manifestation pairs the Guidelines are explicit: the etiology is sequenced first, followed by the manifestation code.

Related References

ICD-10-CM Official GuidelinesICD-10-CM Code LookupICD-10-CM Codes ListCode Lists by Tag

Source: FY 2027 ICD-10-CM Tabular List (CMS and NCHS) and the ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.A. ICD List is not affiliated with CMS or NCHS.