N91.5 — Oligomenorrhea, unspecified
Is N91.5 billable?
Yes, but N91.5 is an unspecified code. N91.5 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, N91.5 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 N91.5 — the more specific alternatives are listed below.
More specific alternatives
N91.5 at a glance
| Code | N91.5 |
|---|---|
| Description | Oligomenorrhea, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does N91.5 group to?
N91.5 sits in MDC 13 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 742Uterine and Adnexa Procedures for Non-Malignancy with CC/MCCsurgical
- 743Uterine and Adnexa Procedures for Non-Malignancy without CC/MCCsurgical
How is N91.5 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to N91.5. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Oligomenorrhea
Inclusion terms
Alternative wording in documentation that is classified to N91.5.
- Hypomenorrhea NOS
Excludes1 — never code together — inherited from N91
The conditions below can never be reported together with N91.5 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- ovarian dysfunction (E28.-)
Excludes2 — not included here — inherited from Chapter 14
The conditions below are not part of N91.5, but a patient may have both at the same time. When documentation supports it, N91.5 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
How long has N91.5 existed?
N91.5 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.
Which codes are confused with N91.5?
ICD-10-CM declares these codes mutually exclusive with N91.5 — exactly one of each pair can be correct for a given encounter.