Z91.0120 — Allergy to eggs, unspecified
Is Z91.0120 billable?
Yes, but Z91.0120 is an unspecified code. Z91.0120 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, Z91.0120 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting Z91.0120 — the more specific alternatives are listed below.
More specific alternatives
Z91.0120 at a glance
| Code | Z91.0120 |
|---|---|
| Description | Allergy to eggs, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to Z91.0120?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name Z91.0120 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 Z91.0120 group to?
Z91.0120 sits in MDC 23 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 951Other Factors Influencing Health Statusmedical
How is Z91.0120 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Z91.0120. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Allergy, allergic › foodNEC › status › eggs (reaction) (to)
- History › personal › allergy › food › eggs
Excludes2 — not included here — inherited from Z91
The conditions below are not part of Z91.0120, but a patient may have both at the same time. When documentation supports it, Z91.0120 and the excluded code may both be reported.
Excludes2 — not included here — inherited from Z91.0
The conditions below are not part of Z91.0120, but a patient may have both at the same time. When documentation supports it, Z91.0120 and the excluded code may both be reported.
- Allergy status to drugs, medicaments, and biological substances (Z88.-)
Excludes2 — not included here — inherited from Z91.01
The conditions below are not part of Z91.0120, but a patient may have both at the same time. When documentation supports it, Z91.0120 and the excluded code may both be reported.
- food additives allergy status (Z91.02)
Code also — inherited from Z77-Z99
Two codes may be needed to describe the condition fully. Whether Z91.0120 is sequenced first depends on the reason for the encounter.
- any follow-up examination (Z08-Z09)
How long has Z91.0120 existed?
Z91.0120 first appears in FY2026.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.