2026 ICD-10-CM Diagnosis Code T48.904SPoisoning by unspecified agents primarily acting on the respiratory system, undetermined, sequela
T48.904S is a billable ICD-10-CM diagnosis code for poisoning by unspecified agents primarily acting on the respiratory system, undetermined, 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 exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T48.904S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Coding GuidelinesGuidance
When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined). If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of agents primarily acting on smooth and skeletal muscles and the respiratory system (T48). 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.
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 |
|---|---|---|---|---|---|---|
| Respiratory drug NEC | T48.901 | T48.902 | T48.903 | T48.904 | T48.905 | T48.906 |
| Respiratory drug NEC::antiasthmatic NEC | T48.901 | T48.902 | T48.903 | T48.904 | T48.905 | T48.906 |
| Respiratory drug NEC::anti-common-cold NEC | T48.901 | T48.902 | T48.903 | T48.904 | T48.905 | T48.906 |
| Respiratory drug NEC::expectorant NEC | T48.901 | T48.902 | T48.903 | T48.904 | T48.905 | T48.906 |
| Respiratory drug NEC::stimulant | T48.901 | T48.902 | T48.903 | T48.904 | T48.905 | T48.906 |
Patient EducationClinical
Poisoning
A poison is any substance that is harmful to your body. You might swallow it, inhale it, inject it, or absorb it through your skin. Any substance can be poisonous if too much is taken. Poisons can include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T48.904S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T48.904SOverview
Is T48.904S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by unspecified agents primarily acting on the respiratory system, undetermined, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T48.904S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by unspecified agents primarily acting on the respiratory system, undetermined itself has resolved, not the original event.
What MS-DRG does T48.904S group to?
When poisoning by unspecified agents primarily acting on the respiratory system, undetermined, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T48.904S 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 poisoning by unspecified agents primarily acting on the respiratory system, undetermined, sequela on inpatient claims.
What is the ICD-9 equivalent of T48.904S?
Under the General Equivalence Mappings, poisoning by unspecified agents primarily acting on the respiratory system, undetermined, sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E989 (late eff inj-undet circ). 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.
