The ICD-10-CM classifies CKD based on severity. The severity of CKD is designated by stages 1-5. Stage 2, code N18.2, equates to mild CKD; stage 3, codes N18.30-N18.32, equate to moderate CKD; and stage 4, code N18.4, equates to severe CKD. Code N18.6, End stage renal disease (ESRD), is assigned when the provider has documented end- stage renal disease (ESRD). If both a stage of CKD and ESRD are documented, assign code N18.6 only.
N91.2
BookmarkAmenorrhea, unspecified
Billable FY2027 2026-10-01 → 2027-09-30
This is the unspecified option. 5 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
How to use this page
Everything the published sources say about one code, on one page.
- Read the Excludes1 block first — it is the one that stops you coding this at all alongside another code.
- Excludes2, Code first, Use additional and Includes follow. A note inherited from a parent category is labelled with the category it came from, so you can see why it applies.
- Official Guidelines sit below. "Guidelines naming this code" cite the code or a range containing it; "Chapter guidance" is the general guidance for its chapter and is the weaker signal.
- Guideline text is quoted verbatim with its section number and page, so you can check it against the published document.
- Risk-model chips show which published CMS models map this code.
What this page does not do
- Guidance is quoted, never paraphrased — a paraphrase of a coding rule is a different rule.
- Medication candidates, where shown, are matched by condition *name* and are offered as candidates for you to judge. They are not "the drugs for this code".
Exclusions9never code together
N00-N99chapter
Excludes2
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes
No further instructional notes apply.
Official Guidelines3
ICD-10-CM Official Guidelines for Coding and Reporting, quoted in full. Published by CMS and NCHS; in the public domain.
Patients who have undergone kidney transplant may still have some form of chronic kidney disease (CKD) because the kidney transplant may not fully restore kidney function. Therefore, the presence of CKD alone does not constitute a transplant complication. Assign the appropriate N18 code for the patient’s stage of CKD and code Z94.0, Kidney transplant status. If a transplant complication such as failure or rejection or other transplant complication is documented, see section I.C.19.g for information on coding complications of a kidney transplant. If the documentation is unclear as to whether the patient has a complication of the transplant, query the provider.
Patients with CKD may also suffer from other serious conditions, most commonly diabetes mellitus and hypertension. The sequencing of the CKD code in relationship to codes for other contributing conditions is based on the conventions in the Tabular List. See I.C.9. Hypertensive chronic kidney disease. See I.C.19. Chronic kidney disease and kidney transplant complications.
Index entries leading here1
- Amenorrhea N91.2
Alongside this code5same parent — N91
Medications1
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.