Z16.11 — Resistance to penicillins
Is Z16.11 billable?
Yes — Z16.11 is billable for FY2027. Z16.11 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. Z16.11 may be submitted for encounters from October 1, 2026 through September 30, 2027.
Z16.11 at a glance
| Code | Z16.11 |
|---|---|
| Description | Resistance to penicillins |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to Z16.11?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name Z16.11 directly.
CMS will reject this code as the principal diagnosis on an inpatient claim. It describes something other than the condition chiefly responsible for the admission.
Which MS-DRGs does Z16.11 group to?
Z16.11 sits in MDC 18 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 867Other Infectious and Parasitic Diseases Diagnoses with MCCmedical
- 868Other Infectious and Parasitic Diseases Diagnoses with CCmedical
- 869Other Infectious and Parasitic Diseases Diagnoses without CC/MCCmedical
As a secondary diagnosis, Z16.11 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is Z16.11 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Z16.11. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Resistance, resistant › organism › to › drug › amoxicillin (to)
- Resistance, resistant › organism › to › drug › ampicillin (to)
- Resistance, resistant › organism › to › drug › penicillins (to)
Inclusion terms
Alternative wording in documentation that is classified to Z16.11.
- Resistance to amoxicillin
- Resistance to ampicillin
Excludes1 — never code together — inherited from Z16
The conditions below can never be reported together with Z16.11 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Code first — inherited from Z16
The underlying condition below must be sequenced before Z16.11. Z16.11 describes a manifestation and cannot be the principal or first-listed diagnosis.
- the infection
How long has Z16.11 existed?
Z16.11 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.