N18.31 is the authoritative medical code for Chronic kidney disease, stage 3a. This classification is used in medical billing and clinical recording to specify the clinical criteria for chronic kidney disease, stage 3a (ICD-10-CM N18.31), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Chronic kidney disease, stage 3a is a billable ICD-10-CM diagnosis code N18.31. Excludes2 (not included here): congenital renal failure P96.0; drug- and heavy-metal-induced tubulo-interstitial and tubular conditions N14.-; extrarenal uremia R39.2; hemolytic-uremic syndrome D59.3-; hepatorenal syndrome K76.7; postpartum hepatorenal syndrome O90.41; posttraumatic renal failure T79.5; prerenal uremia R39.2; renal failure complicating abortion or ectopic or molar pregnancy (O00-O07, O08.4); renal failure following labor and delivery O90.41; renal failure postprocedural N99.0. Code first: any associated:; diabetic chronic kidney disease (E08.22, E09.22, E10.22, E11.22, E13.22); hypertensive chronic kidney disease (I12.-, I13.-). Use additional code: code, if applicable, to identify:; associated cachexia E88.A; kidney transplant status Z94.0.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for N18.31 in the official ICD-10-CM tabular list.
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- congenital renal failure P96.0
- drug- and heavy-metal-induced tubulo-interstitial and tubular conditions N14.-
- extrarenal uremia R39.2
- hemolytic-uremic syndrome D59.3-
- hepatorenal syndrome K76.7
- postpartum hepatorenal syndrome O90.41
- posttraumatic renal failure T79.5
- prerenal uremia R39.2
- renal failure complicating abortion or ectopic or molar pregnancy (O00-O07, O08.4)
- renal failure following labor and delivery O90.41
- renal failure postprocedural N99.0
Code First
Underlying conditions that must be sequenced before this code.
- any associated:
- diabetic chronic kidney disease (E08.22, E09.22, E10.22, E11.22, E13.22)
- hypertensive chronic kidney disease (I12.-, I13.-)
Use Additional Code
Supplementary codes the tabular list directs you to add.
- code, if applicable, to identify:
- associated cachexia E88.A
- kidney transplant status Z94.0
Frequently Asked Questions (FAQ) & Clinical Guidance
Can N18.31 be reported alongside related conditions?
Per Excludes2 instructions, N18.31 and the following may both be reported when both are present: congenital renal failure (P96.0); drug- and heavy-metal-induced tubulo-interstitial and tubular conditions (N14.-); extrarenal uremia (R39.2); hemolytic-uremic syndrome (D59.3-).
Does N18.31 need to be sequenced after another code?
Yes. Code first: any associated:; diabetic chronic kidney disease (E08.22, E09.22, E10.22, E11.22, E13.22); hypertensive chronic kidney disease (I12.-, I13.-).
Is an additional code needed with N18.31?
Use additional code(s) to specify: code, if applicable, to identify:; associated cachexia (E88.A); kidney transplant status (Z94.0).
Codes in This Family (10)
Official ICD-10-CM classifications in the same code family as N18.31, with their registry titles.
- N18 — Chronic kidney disease (CKD)
- N18.1 — Chronic kidney disease, stage 1
- N18.2 — Chronic kidney disease, stage 2 (mild)
- N18.3 — Chronic kidney disease, stage 3 (moderate)
- N18.30 — Chronic kidney disease, stage 3 unspecified
- N18.32 — Chronic kidney disease, stage 3b
- N18.4 — Chronic kidney disease, stage 4 (severe)
- N18.5 — Chronic kidney disease, stage 5
- N18.6 — End stage renal disease
- N18.9 — Chronic kidney disease, unspecified
Indexed Clinical Terms (1)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Disease, diseased, kidney (functional) (pelvis), chronic, stage 3a
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures: