Z16.21
Resistance to vancomycin
This code does not map to a risk-adjusting HCC in the loaded models.
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
Methicillin resistant Staphylococcus aureus infection (A49.02) Methicillin resistant Staphylococcus aureus pneumonia (J15.212) Sepsis due to Methicillin resistant Staphylococcus aureus (A41.02)
the infection
The codes in this category are provided for use as additional codes to identify the resistance and non-responsiveness of a condition to antimicrobial drugs.
Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways: (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury. (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.
Official Guidelines for Z16.21
FY 2026 ›Sections that reference Z16.21
- I.C.1.cInfections resistant to antibioticsChapter 1
… Assign a code from category Z16, Resistance to antimicrobial drugs, following the infection code only if the infection code does not identify drug resistance.
- I.C.1.e.1)(a)Combination codes for MRSA infectionChapter 1
… Do not assign a code from subcategory Z16.11, Resistance to penicillins, as an additional diagnosis. …
- I.C.1.e.1)(b)Other codes for MRSA infectionChapter 1
… Do not assign a code from subcategory Z16.11, Resistance to penicillins.
- I.C.21.c.3)Status
… code, followed by a code from category Z15. Additional codes should be assigned for any applicable family or personal history. Z16 Resistance to antimicrobial drugs This category indicates that a patient has a condition that is resistant to antimicrobial …
- I.B.3Code or codes from A00.0 through T88.9, Z00-Z99.8, U00-U85Conventions & general rules
The appropriate code or codes from A00.0 through T88.9, Z00-Z99.8, and U00-U85 must be used to identify diagnoses, symptoms, conditions, problems, complaints or other reason(s) for the …
- I.C.20.a.1)Used with any code in the range of A00.0-T88.9, Z00-Z99Chapter 20
An external cause code may be used with any code in the range of A00.0-T88.9, Z00-Z99, classification that represents a health condition due to an external cause. …
Showing 6 of 8. Search the guidelines for Z16. Sections whose FY 2026 text names Z16.21, its Z16 category, or a range containing it — the chapter guidance above is the authoritative source.
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