2027 ICD-10-CM Diagnosis Code T38.3X5AAdverse effect of insulin and oral hypoglycemic [antidiabetic] drugs, initial encounter

ICD-10-CM T38.3X5A

CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T38.3X5A is a billable ICD-10-CM diagnosis code for adverse effect of insulin and oral hypoglycemic [antidiabetic] drugs, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793, 917 through 918. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.

Code Identity

ICD-10-CM Code

T38.3X5A

Billable Status

Yes — Valid for Submission

Code Describes

Adverse effect of insulin and oral hypoglycemic [antidiabetic] drugs, initial encounter

Short Description

Adverse effect of insulin and oral hypoglycemic drugs, init

Parent Code

T38.3X5

Adverse effect of insulin and oral hypoglycemic [antidiabetic] drugs

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes

SectionT36-T50Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances

CategoryT38Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified

This CodeT38.3X5AAdverse effect of insulin and oral hypoglycemic [antidiabetic] drugs, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T38.3X5A.

Unacceptable principal diagnosis

There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

Filter synonyms:

Acarbose adverse reaction
Acetohexamide adverse reaction
Adverse reaction caused by human insulin
Adverse reaction following injection of substance
Adverse reaction to biguanide hypoglycemic agent
Adverse reaction to sulfonyluric hypoglycemic
Adverse reaction to zinc insulin
Biguanide adverse reaction
Chlorpropamide adverse reaction
Diabetic drug side effects
Drug-induced anaphylaxis
Fat hypertrophy
Glibenclamide adverse reaction
Glibornuride adverse reaction
Gliclazide adverse reaction
Glipizide adverse reaction
Gliquidone adverse reaction
Glucagon adverse reaction
Glymidine adverse reaction
Insulin adverse reaction
Insulin lipoatrophy
Insulin lipohypertrophy
Insulin-induced anaphylaxis
Isophane insulin adverse reaction
Lipoatrophy caused by injected drug
Localized lipoatrophy
Metformin adverse reaction
Pancytopenia caused by antidiabetic drug
Pancytopenia caused by medication
Protamine zinc insulin adverse reaction
Regular insulin adverse reaction
Sulfonylurea adverse reaction
Tolazamide adverse reaction
Tolbutamide adverse reaction

Coding GuidelinesGuidance

When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified (T38). Use the following options for the applicable episode of care:

A - initial encounter
D - subsequent encounter
S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T38.3X5A: its own notes plus those printed at T38, block T36-T50, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.