Excludes1 pair

R89.5 vs Z22-

R89.5 and Z22 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on R89.5
colonization status (Z22.-)
R89.5

Abnormal microbiological findings in specimens from other organs, systems and tissues

Billable
Chapter 18
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section
R83-R89
Use when the record says
  • Positive culture findings in specimens from other organs, systems and tissues
Indexed under
  • Positive › culture › nipple discharge
  • Positive › culture › synovial fluid
  • Positive › culture › wound secretions
  • Abnormal, abnormality, abnormalities › specimen › specified organ, system and tissue NOS › microbiology
Z22

Carrier of infectious disease

Not billable
Chapter 21
Factors influencing health status and contact with health services
Section
Z20-Z29
Use when the record says
  • colonization status
  • suspected carrier

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027