2026 ICD-10-CM Diagnosis Code T36.3X5AAdverse effect of macrolides, initial encounter
T36.3X5A is a billable ICD-10-CM diagnosis code for adverse effect of macrolides, 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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918. The code is not accepted as a principal diagnosis by the Medicare Code Editor. Coders also document this condition as adverse reaction to oleandomycin. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T36.3X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adverse reaction to oleandomycin
- Azithromycin adverse reaction
- Clarithromycin adverse reaction
- Erythromycin adverse reaction
- Macrolide adverse reaction
- Spiramycin 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 systemic antibiotics (T36). 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 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Azithromycin
a semi-synthetic macrolide antibiotic structurally related to erythromycin. it has been used in the treatment of mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis.Josamycin
a macrolide antibiotic from streptomyces narbonensis. the drug has antimicrobial activity against a wide spectrum of pathogens.Kitasamycin
a macrolide antibiotic produced by streptomyces kitasatoensis. the drug has antimicrobial activity against a wide spectrum of pathogens.Oleandomycin
antibiotic macrolide produced by streptomyces antibioticus.Pristinamycin
an antibiotic mixture originally isolated from streptomyces pristinaspiralis. it is a mixture of compounds from streptogramin group a: pristinamycin iia and iib and from streptogramin group b: pristinamycin ia, pristinamycin ib, pristinamycin ic.Streptogramin A
a specific streptogramin group a antibiotic produced by streptomyces graminofaciens and other bacteria.Streptogramin B
a specific streptogramin group b antibiotic produced by streptomyces graminofaciens and other bacteria.Roxithromycin
semisynthetic derivative of erythromycin. it is concentrated by human phagocytes and is bioactive intracellularly. while the drug is active against a wide spectrum of pathogens, it is particularly effective in the treatment of respiratory and genital tract infections.Spiramycin
a macrolide antibiotic produced by streptomyces ambofaciens. the drug is effective against gram-positive aerobic pathogens, n. gonorrhoeae, and staphylococci. it is used to treat infections caused by bacteria and toxoplasma gondii.Troleandomycin
a macrolide antibiotic that is similar to erythromycin.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T36.3X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T36.3X5AOverview
Is T36.3X5A (Adverse effect of macrolides) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of macrolides, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T36.3X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of macrolides, such as an emergency visit or first evaluation.
What MS-DRG does T36.3X5A group to?
On inpatient claims, adverse effect of macrolides, initial encounter maps to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T36.3X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of macrolides, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What is the ICD-9 equivalent of T36.3X5A?
Under the General Equivalence Mappings, adverse effect of macrolides, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E930.3 (adv eff erythromycin). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
