2026 ICD-10-CM Diagnosis Code T39.1X5SAdverse effect of 4-Aminophenol derivatives, sequela
T39.1X5S is a billable ICD-10-CM diagnosis code for adverse effect of 4-Aminophenol derivatives, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. Coders also document this condition as adverse reaction caused by acetaminophen. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T39.1X5S.
Present on Admission (POA)Billing
T39.1X5S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adverse reaction caused by acetaminophen
- Adverse reaction to acetanilide
- Adverse reaction to phenacetin
- Para-aminophenol derivative 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 nonopioid analgesics, antipyretics and antirheumatics (T39). 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
Acetaminophen
analgesic antipyretic derivative of acetanilide. it has weak anti-inflammatory properties and is used as a common analgesic, but may cause liver, blood cell, and kidney damage.Arylsulfotransferase
a sulfotransferase that catalyzes the sulfation of a phenol in the presence of 3'-phosphoadenylylsulfate as sulfate donor to yield an aryl sulfate and adenosine 3',5'-bisphosphate. a number of aromatic compounds can act as acceptors; however, organic hydroxylamines are not substrates. sulfate conjugation by this enzyme is a major pathway for the biotransformation of phenolic and catechol drugs as well as neurotransmitters. ec 2.8.2.1.Cytochrome P-450 CYP1A2
a cytochrome p450 enzyme subtype that has specificity for relatively planar heteroaromatic small molecules, such as caffeine and acetaminophen.Phenacetin
a phenylacetamide that was formerly used in analgesics but nephropathy and methemoglobinemia led to its withdrawal from the market. (from smith and reynard, textbook of pharmacology,1991, p431)
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.
| Substance | Accidental | Self-harm | Assault | Undetermined | Adverse Effect | Underdosing |
|---|---|---|---|---|---|---|
| P-Acetamidophenol | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Acetaminophen | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Acetaminosalol | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Acetanilide | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Acetophenetedin | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| 4-Aminophenol derivatives | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Bromo-seltzer | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Exalgin | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Panadol | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Para-acetamidophenol | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Para-aminophenol derivatives | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Paracetamol | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
| Phenacetin | T39.1X1 | T39.1X2 | T39.1X3 | T39.1X4 | T39.1X5 | T39.1X6 |
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 T39.1X5S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T39.1X5SOverview
Is T39.1X5S (Adverse effect of 4-Aminophenol derivatives) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of 4-Aminophenol derivatives, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T39.1X5S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the adverse effect of 4-Aminophenol derivatives itself has resolved, not the original event.
What MS-DRG does T39.1X5S group to?
On inpatient claims, adverse effect of 4-Aminophenol derivatives, sequela maps to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T39.1X5S be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of 4-Aminophenol derivatives, sequela describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Is T39.1X5S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for adverse effect of 4-Aminophenol derivatives, sequela on inpatient claims.
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.
