ICD-10 Codes for Diabetes: A Complete Documentation & Billing Guide

If you bill or document diabetes encounters, the codes you choose directly affect how much your practice gets paid, and whether your claims survive an audit.

This guide covers every ICD-10 code for diabetes mellitus from E08 through E13, including all subcodes, complication hierarchies, CPT pairings, denial triggers, documentation error patterns, and MDM complexity scoring. Whether you are a new coder building foundational knowledge or an experienced biller looking for a reliable reference, this is the only diabetes coding resource you need.

We cover:

• The complete ICD-10 diabetes code hierarchy (E08 to E13) with all subcodes and descriptions
• How to code every complication type, kidney, eye, nerve, circulation, skin, and blood sugar
• CPT codes commonly billed alongside diabetes diagnoses
• Claim denial triggers specific to diabetes coding
• Common documentation errors that trigger audits
• MDM complexity scoring by diagnosis type
• Long-term medication codes (metformin, insulin, glipizide, and more)
• Steroid-induced hyperglycemia, a frequently miscoded scenario
• How to use physician queries correctly
• A downloadable cheat sheet at the end

Let’s start at the foundation.

Section 1: Understanding ICD-10-CM: The Basics

ICD-10-CM stands for International Classification of Diseases, 10th Revision, Clinical Modification. It is the standardized diagnostic coding system used across all U.S. healthcare billing, maintained jointly by CMS and the CDC’s National Center for Health Statistics (CDC NCHS, ICD-10-CM). Each code is a compact clinical statement, a short string of characters that communicates the type of disease, its cause, its complications, and its severity to every payer, auditor, and risk adjustment model simultaneously.

How a Code is Built

Every ICD-10-CM code has up to seven characters. Each character adds a layer of clinical detail. Using the code E11.3511 as an example:

• E11 = Type 2 diabetes mellitus
• .35 = with proliferative diabetic retinopathy
• 1 = with macular edema
• 1 = right eye

Five distinct clinical facts in seven characters. That precision is why using vague or unspecified codes when specific ones exist is a compliance risk, payers, auditors, and HCC risk models all notice.

The foundational rule:

Always use the most specific code the documentation supports. If documentation supports a detailed code and you use a general one, that is undercoding, and it costs your practice money.

Section 2: The Five Diabetes Categories in ICD-10

ICD-10-CM does not treat all diabetes as the same disease. There are five main categories, and selecting the wrong one is one of the most common compliance errors.

Code	Type	Key Rule
E08	Diabetes due to underlying condition	Underlying condition coded FIRST
E09	Drug or chemical-induced diabetes	Adverse effect T-code coded FIRST
E10	Type 1 diabetes mellitus	No Z79.4 needed, insulin is implied
E11	Type 2 diabetes mellitus (default)	Add Z79.4 for insulin; Z79.84 for oral agents
E13	Other specified diabetes mellitus	Post-surgical, MODY, neonatal
O24.4	Gestational diabetes	Obstetrics chapter only, not E codes

Note: There is no E12. It was deleted from a prior version of the code set. If it appears on an old superbill, update it immediately.

Choosing the Right Category

Work through this logic before assigning any diabetes code:

• Did another disease cause it? E08 (code that disease first)
• Did a drug cause it? E09 (code the T-code adverse effect first)
• Is it explicitly documented as Type 1? E10
• None of the above? Default to E11

The sequencing rules for E08 and E09 are not optional. The ICD-10-CM Official Guidelines for Coding and Reporting FY2026 (CMS/NCHS) require the causative condition to be sequenced before the diabetes code.

Section 3: Complete ICD-10 Code Lookup Table: E08 Through E13

This is the full hierarchy of diabetes codes organized by category and complication type. Use this as your primary reference when coding any diabetes encounter. All codes are verified against the FY2026 ICD-10-CM code set, effective October 1, 2025 through September 30, 2026. For real-time lookups, use the CDC ICD-10-CM Browser Tool or ICD10Data.com, E08–E13 Diabetes Codes.

E08

Diabetes Mellitus Due to Underlying Condition

Code	Description
E08.00	With hyperosmolarity without nonketotic hyperglycemic-hyperosmolar coma (NKHHC)
E08.01	With hyperosmolarity with coma
E08.10	With ketoacidosis without coma
E08.11	With ketoacidosis with coma
E08.21	With diabetic nephropathy
E08.22	With diabetic chronic kidney disease, stage 1–2
E08.29	With other diabetic kidney complication
E08.311 to E08.359	With diabetic retinopathy (various types and laterality)
E08.40	With diabetic neuropathy, unspecified
E08.41	With diabetic mononeuropathy
E08.42	With diabetic polyneuropathy
E08.43	With diabetic autonomic (poly)neuropathy
E08.44	With diabetic amyotrophy
E08.49	With other diabetic neurological complication
E08.51	With diabetic peripheral angiopathy without gangrene
E08.52	With diabetic peripheral angiopathy with gangrene
E08.610	With diabetic neuropathic arthropathy
E08.620	With diabetic dermatitis
E08.621	With foot ulcer (pair with L97.x)
E08.622	With other skin ulcer (pair with L98.x)
E08.628	With other skin complication
E08.630	With periodontal disease
E08.638	With other oral complication
E08.641	With hypoglycemia with coma
E08.649	With hypoglycemia without coma
E08.65	With hyperglycemia
E08.69	With other specified complication
E08.8	With unspecified complications
E08.9	Without complications

E09

Drug or Chemical Induced Diabetes Mellitus

Code	Description
E09.00	With hyperosmolarity without NKHHC
E09.01	With hyperosmolarity with coma
E09.10	With ketoacidosis without coma
E09.11	With ketoacidosis with coma
E09.21	With diabetic nephropathy
E09.22	With diabetic CKD, stage 1–2
E09.29	With other diabetic kidney complication
E09.311–E09.359	With diabetic retinopathy (various types and laterality)
E09.40	With diabetic neuropathy, unspecified
E09.41	With diabetic mononeuropathy
E09.42	With diabetic polyneuropathy
E09.43	With diabetic autonomic neuropathy
E09.44	With diabetic amyotrophy
E09.49	With other diabetic neurological complication
E09.51	With diabetic peripheral angiopathy without gangrene
E09.52	With diabetic peripheral angiopathy with gangrene
E09.621	With foot ulcer (pair with L97.x)
E09.622	With other skin ulcer (pair with L98.x)
E09.641	With hypoglycemia with coma
E09.649	With hypoglycemia without coma
E09.65	With hyperglycemia
E09.9	Without complications

E10

Type 1 Diabetes Mellitus

Code	Description
E10.10	With ketoacidosis without coma
E10.11	With ketoacidosis with coma
E10.21	With diabetic nephropathy
E10.22	With diabetic CKD, stage 1–2
E10.29	With other diabetic kidney complication
E10.311–E10.359	With diabetic retinopathy (various types and laterality)
E10.40	With diabetic neuropathy, unspecified
E10.41	With diabetic mononeuropathy
E10.42	With diabetic polyneuropathy
E10.43	With diabetic autonomic neuropathy
E10.44	With diabetic amyotrophy
E10.51	With peripheral angiopathy without gangrene
E10.52	With peripheral angiopathy with gangrene
E10.610	With diabetic neuropathic arthropathy (Charcot joint)
E10.620	With diabetic dermatitis
E10.621	With foot ulcer (pair with L97.x)
E10.622	With other skin ulcer (pair with L98.x)
E10.630	With periodontal disease
E10.641	With hypoglycemia with coma
E10.649	With hypoglycemia without coma
E10.65	With hyperglycemia
E10.9	Without complications

E11

Type 2 Diabetes Mellitus (Most Commonly Used)

Code	Description
E11.00	With hyperosmolarity without NKHHC
E11.01	With hyperosmolarity with coma
E11.10	With ketoacidosis without coma
E11.11	With ketoacidosis with coma
E11.21	With diabetic nephropathy
E11.22	With diabetic CKD, stage 1–2
E11.29	With other diabetic kidney complication
E11.311	With mild NPDR, right eye, with macular edema
E11.3111	With mild NPDR, right eye, with macular edema (ICD-10-CM 2024+)
E11.3112	With mild NPDR, right eye, without macular edema
E11.3211	With moderate NPDR, right eye, with macular edema
E11.3212	With moderate NPDR, right eye, without macular edema
E11.3311	With severe NPDR, right eye, with macular edema
E11.3411	With proliferative DR, right eye, with macular edema
E11.3511	With proliferative DR, right eye, with macular edema (stable)
E11.36	With diabetic cataract
E11.39	With other diabetic ophthalmic complication
E11.40	With diabetic neuropathy, unspecified
E11.41	With diabetic mononeuropathy
E11.42	With diabetic polyneuropathy
E11.43	With diabetic autonomic neuropathy
E11.44	With diabetic amyotrophy
E11.49	With other diabetic neurological complication
E11.51	With peripheral angiopathy without gangrene
E11.52	With peripheral angiopathy with gangrene
E11.610	With diabetic neuropathic arthropathy (Charcot joint)
E11.620	With diabetic dermatitis
E11.621	With foot ulcer (pair with L97.x)
E11.622	With other skin ulcer (pair with L98.x)
E11.628	With other skin complication
E11.630	With periodontal disease
E11.638	With other oral complication
E11.641	With hypoglycemia with coma
E11.649	With hypoglycemia without coma
E11.65	With hyperglycemia
E11.69	With other specified complication
E11.8	With unspecified complications
E11.9	Without complications

E13

Other Specified Diabetes Mellitus

E13 applies to post-pancreatectomy diabetes, MODY, neonatal diabetes, and other forms not captured by E08 to E11. The complication structure mirrors E11 exactly (E13.42 = polyneuropathy, E13.621 = foot ulcer, etc.).

FY2026 Update: A new code, E11.A (Type 2 diabetes mellitus in remission), was introduced effective October 1, 2025. It is assigned based on provider documentation that diabetes is in remission, defined as achieving normal glucose levels without medication for a sustained period. Always verify against the current code set before use.

Section 4: Kidney Complication Codes, Required Companion Codes

Whenever you use a diabetic nephropathy or CKD code, a second N18.x code is mandatory.

Diabetes Extension	CKD Stage	Required Companion Code
.11	Stage 1 or 2	N18.1 or N18.2
.12	Stage 3a or 3b	N18.31 or N18.32
.13	Stage 4	N18.4
.14	Stage 5 or ESRD	N18.5 or N18.6
.1	Stage unspecified	N18.9

Never submit E11.12 without N18.3x. One code without the other is a claim waiting to be denied or queried.

Section 5: Long-Term Medication Codes

These secondary codes are required whenever a patient is on the listed medication. Missing them is a common undercoding error. Per the ICD-10-CM Official Guidelines FY2026, Section I.C.4.a.3 .

Medication / Situation	ICD-10-CM Code	Notes
Long-term insulin use	Z79.4	Add for E08, E09, E11, E13 on insulin. NEVER add to E10, implied.
Long-term oral hypoglycemic use (metformin, glipizide, etc.)	Z79.84	Add for any diabetes type managed with oral agents
Long-term metformin specifically	Z79.84	Same code, metformin is an oral hypoglycemic
Long-term glipizide (sulfonylurea)	Z79.84	Same code, sulfonylureas are oral hypoglycemics
On both insulin AND oral agents	Z79.4 ONLY	Per official guidelines: when on both, assign Z79.4 only, do NOT add Z79.84
On both insulin AND injectable non-insulin (e.g. GLP-1)	Z79.4 + Z79.85	Assign both codes
On both oral agents AND injectable non-insulin (e.g. GLP-1)	Z79.84 + Z79.85	Assign both codes
Diet-controlled only	No Z code needed	—
Long-term injectable GLP-1 agonist (semaglutide, liraglutide, dulaglutide)	Z79.85	Injectable non-insulin antidiabetic drug, NOT Z79.84
Long-term oral semaglutide (Rybelsus)	Z79.84	Oral formulation → oral hypoglycemic code
Long-term SGLT2 inhibitor (empagliflozin, dapagliflozin)	Z79.84	Oral agents → oral hypoglycemic code
Resolved complication (e.g., healed ulcer)	Z86.39	Personal history of complications of diabetes

Common error:

Z79.4 should NOT be assigned when insulin is given temporarily (e.g., during a hospital encounter to control blood sugar). It is for established long-term use only.

Section 6: CPT Codes Commonly Billed With Diabetes Diagnoses

Pairing diabetes ICD-10 codes with the correct CPT codes is essential for clean claim submission and audit defense.

CPT Code	Description	Common Diabetes ICD-10 Pairing
99213 to 99215	Office/outpatient E&M visit (established patient)	E11.x, E10.x with Z79.4/Z79.84
99202 to 99205	Office/outpatient E&M visit (new patient)	E11.9, E11.42, E11.65
83036	Hemoglobin A1c	E11.x (monitoring, not a standalone diagnosis code)
82962	Glucose, blood by glucose monitoring device	E11.649, E11.65
99091	Remote patient monitoring, collection and interpretation	E11.x (chronic management)
99473 to 99474	Self-measured blood pressure monitoring	E11.x with hypertension (I10)
99490	Chronic care management, first 20 minutes	E11.x with 2+ chronic conditions
99487 to 99489	Complex chronic care management	E11.x with multiple complications
92134	Scanning computerized ophthalmic diagnostic imaging (retina)	E11.311 to E11.359
92228	Remote imaging for detection of diabetic retinopathy	E11.311 to E11.359
11721	Debridement of nails	E11.621 with L97.x
97597–97598	Debridement, open wound	E11.621 with L97.x
97602	Non-selective debridement	E11.622 with L97.x
G0108	Diabetes outpatient self-management training, individual	E11.x (new diagnosis or significant change)
G0109	Diabetes outpatient self-management training, group	E11.x
95905 to 95913	Nerve conduction studies	E11.42 (polyneuropathy)
95999	Unlisted neurological procedure	E11.43 (autonomic neuropathy workup)

Section 7: Steroid-Induced Hyperglycemia and Diabetes, A Frequently Miscoded Scenario

This is one of the most commonly miscoded situations in diabetes billing, and it is worth its own dedicated section.

Understanding the Distinction

There are two separate clinical scenarios that coders often confuse:

Scenario A: Steroid-induced hyperglycemia (not yet diabetes)

The patient has elevated blood sugar in response to steroids, but the physician has not documented a formal diabetes diagnosis. This is not E09. The correct code is R73.09 (Other abnormal glucose), paired with the adverse effect T-code for the steroid.

Scenario B: Steroid-induced diabetes (formal diagnosis)

The physician explicitly documents “diabetes mellitus due to steroid use” or “drug-induced diabetes.” Now E09 applies, but the T-code must be sequenced first.

Coding Steroid-Induced Diabetes Correctly

Step 1: Identify the drug. The most common culprits:

• Prednisone / prednisolone → T38.0X5A (adverse effect, glucocorticoids)
• Dexamethasone → T38.0X5A
• Methylprednisolone → T38.0X5A
• Antipsychotics (olanzapine, clozapine) → T43.595A or T43.505A
• Tacrolimus (transplant drug) → T45.1X5A

Step 2: Sequence the T-code first, then E09.x, then the complication code, then Z79.4 if insulin was started.

Example: Prednisone-induced diabetes, no complications, patient started on insulin:

• T38.0X5A (adverse effect, glucocorticoids, initial encounter)
• E09.9 (drug-induced diabetes, no complications)
• Z79.4 (long-term insulin use)

Example: Steroid-induced diabetes with polyneuropathy:

• T38.0X5A
• E09.42 (drug-induced diabetes with polyneuropathy)
• Z79.4 (if on insulin)

The Most Common Error Here

Defaulting to E11 because the patient is a “new diabetic.” If steroids caused the diabetes, E09 is always correct regardless of the patient’s age, weight, or family history. E11 is only the default when no other cause is documented.

Section 8: MDM Complexity Scoring by Diabetes Diagnosis

Medical Decision Making (MDM) complexity determines the level of E&M code you can bill. Diabetes diagnoses contribute to MDM scoring in the “number and complexity of problems addressed” column. Here is how common diabetes scenarios score:

Clinical Scenario	MDM Problem Category	MDM Level Contribution
Type 2 diabetes, stable, no complications (E11.9)	Chronic illness, stable	Moderate (supports 99214)
Type 2 diabetes with ONE stable complication (e.g., E11.42)	Chronic illness with mild exacerbation or progression	Moderate (supports 99214)
Type 2 diabetes with MULTIPLE complications (e.g., E11.42 + E11.12 + E11.311)	Chronic illness with severe exacerbation or progression	High (supports 99215)
Hypoglycemic episode with loss of consciousness (E11.641)	Acute illness with systemic symptoms	High (supports 99215)
New-onset diabetes, type not yet established	New problem requiring additional workup	Moderate (supports 99214)
Steroid-induced diabetes, newly diagnosed (E09.9)	New problem requiring additional workup	Moderate (supports 99214)
Diabetic foot ulcer requiring wound care (E11.621 + L97.x)	Chronic illness with severe exacerbation	High (supports 99215)
Diabetic ketoacidosis (E11.10 or E11.11)	Acute or chronic illness posing threat to life	High (supports 99215)
Gestational diabetes, diet-controlled (O24.410)	Chronic illness with mild exacerbation	Moderate
Type 2 diabetes + CKD stage 4 (E11.13 + N18.4)	Chronic illness with severe exacerbation	High (supports 99215)

Key Rule:

MDM is based on the complexity of problems addressed at that specific encounter, not the patient’s entire medical history. Document what you actually addressed. If you reviewed and managed three diabetes complications at one visit, that drives a High MDM level.

Section 9: Common Documentation Errors That Trigger Audits

Error	What the Auditor Sees	How to Fix It
Using E11.9 for every diabetic patient regardless of chart content	Undercoding pattern, suggests documentation review is not happening	Review full chart including specialist notes before assigning any diabetes code
CKD and diabetes documented but no causal link stated	Cannot use E11.12, two conditions listed separately do not equal one combination code	Physician must write “diabetic nephropathy” or “CKD due to Type 2 diabetes”
E11.52 (gangrene) used without the word “gangrene” in documentation	Overcoding, the code requires explicit physician use of the word	Query the physician; do not code gangrene from wound appearance alone
Retinopathy coded without laterality (unspecified eye)	Undercoding, eye codes require right, left, or bilateral specification	Read ophthalmology note for laterality; query if missing
E08 or E09 sequenced before the underlying cause or drug T-code	Wrong sequencing, guaranteed audit flag	Cause always first: underlying disease or T-code before E08/E09
Z79.4 added to E10 codes	Redundant code, Type 1 patients are always on insulin by definition	Remove Z79.4 whenever the root code is E10.x
Resolved complications coded as active	Overcoding, healed ulcers, resolved episodes should not appear as active diagnoses	Use Z86.39 for personal history of resolved diabetes complications
CKD stage missing when coding diabetic nephropathy	Incomplete claim, E11.12 without N18.x is an incomplete code pair	Always pair nephropathy codes with corresponding N18.x stage code
Metformin on medication list but Z79.84 not coded	Undercoding, medication use should be captured	Review medication list at every visit and add Z79.84 when applicable
Steroid-induced diabetes coded as E11	Wrong category, drug causation requires E09	When a drug caused the diabetes, E09 applies regardless of clinical presentation
HbA1c used as basis for coding diabetes or complications	Lab results alone cannot be coded, physician diagnosis required	A high HbA1c supports physician documentation but cannot substitute for it
Complication code used without physician explicitly linking it to diabetes	Overcoding, “patient has CKD and diabetes” ≠ diabetic nephropathy	The physician must draw the causal connection explicitly in the note

Section 10: Claim Denial Triggers Specific to Diabetes Coding

These are the denial patterns that show up most frequently in diabetes claims. Knowing them before submission prevents revenue loss.

Denial Trigger	Denial Type	Prevention Strategy
Missing companion code (e.g., E11.12 without N18.x)	Coding error, incomplete claim	Build a mandatory code-pair checklist into your workflow
Wrong sequencing for E08 or E09	Coding error	Train: cause before diabetes, always
E11.621 (foot ulcer) submitted without L97.x	Missing required secondary code	Foot ulcer codes always need L97.x for site and severity
Retinopathy code without laterality specified	Insufficient specificity	Use eye-specific codes; query physician if laterality is absent
Diagnosis not supported by documentation	Medical necessity denial	No code can exist without explicit physician documentation
Z79.4 missing for Type 2 patient on insulin	Undercoding, risk adjustment gap	Build a medication cross-check into every diabetes encounter workflow
Diabetes code submitted without any E&M documentation supporting it	Medical necessity	Ensure the visit note supports the diagnosis at every encounter
E09.x submitted without the T-code for the causative drug	Sequencing error, claim rejected	T-code must always precede E09
Gangrene coded (E11.52) without documented word “gangrene”	Overcoding, likely denial and audit flag	Do not code .52 from wound appearance alone
HCC capture missed, E11.9 used for patient with documented complications	Risk adjustment gap, underpayment	Complications must be coded every year they are active, HCC does not carry forward
Duplicate claim for same date of service	Administrative denial	Review claim history before resubmission
Annual HbA1c not billed with correct diagnosis linkage	Medically necessary service not linked to diagnosis	Always link 83036 to the diabetes ICD-10 code on the same claim

Section 11: HCC Risk Adjustment, Why Your Codes Directly Affect Revenue

HCC stands for Hierarchical Condition Category. It is the risk-scoring model used by Medicare Advantage plans and many commercial payers to calculate how much a practice is paid to manage its patient population. The logic: sicker patients require more resources, so practices managing genuinely sick populations are paid more, but only if the diagnosis codes reflect that complexity.

Important: CMS-HCC Version 28, Updated HCC Numbers (Effective January 1, 2025)

As of January 1, 2025, CMS completed the full transition from ‘@ + ‘HCC Version 24 to Version 28‘ + @’ . Diabetes HCC numbers have changed. Coders and practice managers working with Medicare Advantage plans must use the V28 numbers.

Three HCC tiers for diabetes (CMS-HCC V28, current as of 2025–2026):

• HCC 36: Diabetes with acute complications (highest risk weight)
• HCC 37: Diabetes with chronic complications: neuropathy, nephropathy, retinopathy, circulatory problems
• HCC 38: Diabetes without complications (E11.9), lowest risk weight

Note: Older resources may reference V24 numbers (HCC 17, 18, 19). These may still apply to legacy contracts, but for Medicare Advantage plan year 2025 onward, V28 applies.

When a patient who genuinely has polyneuropathy and CKD stage 3 is coded as E11.9 every visit, they fall into HCC 38 (V28). The practice is paid as if that patient is far healthier than they are. Across 50 or 150 patients, this becomes a significant revenue gap.

Critical HCC rule:

Diagnoses do not carry forward year to year. Every active condition must appear on at least one claim per calendar year. If you captured diabetic neuropathy in January but the patient didn’t return until the following year and you didn’t re-code it, it disappears from the risk model for the gap year.

Section 12: Documentation Requirements Before You Can Code

You cannot code what is not written. Here is exactly what needs to be in the chart for each code type:

What You Want to Code	What the Chart Must Say
Any diabetes code	Physician must explicitly state the type of diabetes
Any complication code	Physician must link the complication to the diabetes explicitly (e.g., “diabetic neuropathy,” not just “neuropathy”)
E08 (underlying condition)	Physician must name the condition AND state it caused the diabetes
E09 (drug-induced)	Physician must name the specific drug AND state it caused the diabetes
Eye codes with laterality	Ophthalmology or optometry note must specify right, left, or bilateral
CKD companion codes	Physician must document the CKD stage, cannot be inferred from lab values alone
E11.52 (gangrene)	The word “gangrene” must appear in physician documentation
E11.621 (foot ulcer)	Must be paired with L97.x for location and severity
Z79.4	Patient must be currently using insulin (Type 2, E08, E09, E13 only)
Z79.84	Patient must be currently using oral hypoglycemic medication

When to Send a Physician Query

Send a formal query when:

• High HbA1c or diabetes medications appear on record but no formal diabetes diagnosis is documented
• A specialist note mentions a complication but the treating physician hasn’t connected it to the diabetes
• The type of diabetes is ambiguous (young thin patient on insulin with no Type 2 risk factors)
• A drug known to cause diabetes is on the medication list but no causal connection has been drawn
• CKD is documented but the stage is not specified
• Retinopathy is documented but the eye is not specified

Queries must be objective. Present the clinical facts and ask for clarification. Do not suggest a specific answer or code.

Section 13: Coding Multiple Complications, Full Examples

Example A: Routine Type 2, No Complications

58 year old woman, Type 2 diabetes, on metformin twice daily, HbA1c 7.2%, no documented complications.

• E11.9 (Type 2 without complications, confirmed by full chart review)
• Z79.84 (long-term oral hypoglycemic use)

Example B: Complex Type 2 with Multiple Complications

67 year old man, Type 2 diabetes on nightly insulin and metformin. Note documents peripheral polyneuropathy, moderate non-proliferative retinopathy left eye without macular edema, CKD stage 3 due to diabetic nephropathy.

• E11.42 (polyneuropathy)
• E11.3212 (moderate NPDR, left eye, no macular edema)
• E11.12 (diabetic CKD stage 3)
• N18.3 (CKD stage 3, required companion)
• Z79.4 (long-term insulin, only Z79.4 needed when on both insulin and oral agents per official guidelines)

Note: Z79.84 is NOT added here because per ICD-10-CM Official Guidelines, when a patient uses both insulin and oral hypoglycemics, only Z79.4 is assigned.

MDM level: High → supports 99215

Example C: Steroid-Induced Diabetes

45 year old woman on long-term prednisone for rheumatoid arthritis. Physician documents new-onset diabetes due to steroid use. No complications. Started on insulin.

• T38.0X5A (adverse effect, glucocorticoids, initial encounter)
• E09.9 (drug-induced diabetes, no complications)
• Z79.4 (long-term insulin use)

Do not use E11, steroid causation is documented, so E09 is required.

Example D: Diabetes Due to Chronic Pancreatitis

Patient with chronic pancreatitis. Physician documents “diabetes mellitus due to chronic pancreatitis.” No complications.

• K86.1 (chronic pancreatitis, coded first)
• E08.9 (diabetes due to underlying condition, no complications)

Example E: Diabetic Foot Ulcer

Type 2 diabetic on insulin. Right foot plantar ulcer, stage 2, documented as diabetic foot ulcer.

• E11.621 (Type 2 with foot ulcer)
• L97.411 (non-pressure chronic ulcer, right heel and midfoot, limited to breakdown of skin)
• Z79.4 (long-term insulin use)

Section 14: Quick Reference Tables

Master Category Guide

Code	Type	Key Rule
E08	Caused by another disease	Underlying condition coded first
E09	Caused by a drug	Adverse effect T-code coded first
E10	Type 1	No Z79.4 needed, insulin is implied
E11	Type 2 (default)	Add Z79.4 for insulin; Z79.84 for oral agents
E13	Other specified	Post-surgical, MODY, neonatal
O24.4	Gestational	Obstetrics chapter only; not E codes

Complication Extension Guide

Extension	Complication	Always Add
.1x	Kidney / nephropathy	N18.x for CKD stage
.2x	Peripheral vascular	Gangrene code if documented
.3x	Eye / retinopathy	Laterality required (1=right, 2=left, 3=both)
.4x	Nerve / neuropathy	Nothing extra required
.5x	Circulatory	Nothing extra required
.621	Foot ulcer	L97.x for ulcer location and severity
.622	Other skin ulcer	L98.x for ulcer detail
.64x	Hypoglycemia	Specify with or without coma
.65	Hyperglycemia	Nothing extra required
.9	No complications	Confirm no complications in full chart review

Medication Add-On Codes

Situation	Code to Add
E08/E09/E11/E13 patient on insulin	Z79.4
Any diabetes type on oral hypoglycemics (metformin, glipizide, SGLT2 inhibitors, oral semaglutide)	Z79.84
On BOTH insulin AND oral agents	Z79.4 only (per official guidelines, do NOT add Z79.84)
On injectable GLP-1 (semaglutide injection, liraglutide, dulaglutide)	Z79.85
On both insulin AND injectable non-insulin drug	Z79.4 + Z79.85
Diet-controlled only	No Z code needed
Resolved complication	Z86.39

Automate Your Diabetes Billing Audits with OmniMD

Knowing the codes is only half the battle, applying them consistently across every encounter is where practices lose revenue. OmniMD’s AI Medical Coder automatically suggests the right ICD-10 codes from clinical documentation, catches missing companion codes, and flags undercoded encounters before claims are submitted. Combined with AI RCM, it tracks HCC capture gaps and denial risks across your entire diabetic patient panel, so nothing slips through.

FAQs:

Q: What is the ICD-10 code for Type 2 diabetes?

E11.9 is the base code for Type 2 diabetes without complications. However, if the patient has any documented complication, a more specific E11.x code must be used.

Q: What is the ICD-10 code for Type 1 diabetes?

E10.9 for Type 1 without complications. Add the appropriate extension for any complication (e.g., E10.42 for polyneuropathy).

Q: What ICD-10 code is used for gestational diabetes?

Gestational diabetes is coded in the obstetrics chapter, not with E codes. Use O24.410 (diet-controlled), O24.414 (insulin-controlled), or O24.415 (oral medication-controlled).

Q: Do I add Z79.4 for Type 1 diabetes patients on insulin?

No. Z79.4 is redundant for E10 codes because Type 1 patients are always insulin-dependent by definition. Z79.4 is only added for Type 2 (E11), E08, E09, and E13 patients who use insulin.

Q: What is the ICD-10 code for diabetic neuropathy?

E11.40 (Type 2, unspecified neuropathy), E11.41 (mononeuropathy), E11.42 (polyneuropathy, most common), E11.43 (autonomic neuropathy). Specify the type when the physician documents it.

Q: What is the ICD-10 code for diabetic nephropathy?

E11.21 for diabetic nephropathy. For CKD staging, use E11.22 (stage 1–2), E11.12 (stage 3), E11.13 (stage 4), or E11.14 (stage 5/ESRD), always paired with the corresponding N18.x code.

Q: What ICD-10 code is used for steroid-induced diabetes?

E09.x, with the steroid’s adverse effect T-code sequenced first. For prednisone, use T38.0X5A before E09.9.

Q: What is the difference between E11.51 and E11.52?

E11.51 is peripheral angiopathy without gangrene. E11.52 is peripheral angiopathy with gangrene. The word “gangrene” must be explicitly documented by the physician to use E11.52.

Q: Can I code diabetes from a lab result or medication list alone?

No. A physician or qualified provider must explicitly document the diagnosis in the medical record. An elevated HbA1c or the presence of metformin on a medication list is not sufficient by itself.

Q: How often do I need to code active diabetes complications?

Every calendar year. HCC risk adjustment models (CMS-HCC V28) do not carry diagnoses forward year to year. Every active chronic condition must appear on at least one claim per calendar year. (CMS HCC Risk Adjustment)

Q: What CPT code do I bill with diabetes self-management training?

G0108 for individual DSMT sessions, G0109 for group sessions. These require a written order and can be billed on initial diagnosis or when significant changes in the treatment plan occur.

Q: What is the ICD-10 code for metformin use?

Z79.84, long-term (current) use of oral hypoglycemic drugs. This applies to metformin, glipizide, and all other oral diabetes medications.