2027 ICD-10-CM Diagnosis Code T36.6X4SPoisoning by rifampicins, undetermined, sequela
T36.6X4S is a billable ICD-10-CM diagnosis code for poisoning by rifampicins, 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 2027 (October 1, 2026 through September 30, 2027) 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
T36.6X4S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances (T36-T50).
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 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 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 T36.6X4S: its own notes plus those printed at T36, block T36-T50, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- adverse effect of correct substance properly administered
- poisoning by overdose of substance
- poisoning by wrong substance given or taken in error
- underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- toxic reaction to local anesthesia in pregnancy (O29.3-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Code First
The underlying condition named in the note is sequenced before this code.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category T36
- Ainitial encounter
- Dsubsequent encounter
- Ssequela this code
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name T36.6X4S, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Rifabutin
a broad-spectrum antibiotic that is being used as prophylaxis against disseminated mycobacterium avium complex infection in hiv-positive patients.Rifampin
a semisynthetic antibiotic produced from streptomyces mediterranei. it has a broad antibacterial spectrum, including activity against several forms of mycobacterium. in susceptible organisms it inhibits dna-dependent rna polymerase activity by forming a stable complex with the enzyme. it thus suppresses the initiation of rna synthesis. rifampin is bactericidal, and acts on both intracellular and extracellular organisms. (from gilman et al., goodman and gilman's the pharmacological basis of therapeutics, 9th ed, p1160)Rifaximin
a synthetic rifamycin derivative and anti-bacterial agent that is used for the treatment of gastroenteritis caused by escherichia coli infections. it may also be used in the treatment of hepatic encephalopathy.
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 |
|---|---|---|---|---|---|---|
| Ansamycin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Isoniazid::with::rifampicin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifabutin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifamide | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifampicin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifampin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifamycin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
| Rifaximin | T36.6X1 | T36.6X2 | T36.6X3 | T36.6X4 | T36.6X5 | T36.6X6 |
Patient EducationClinical
Antibiotics
Antibiotics are medicines that fight bacterial infections in people and animals. They work by killing the bacteria or by making it hard for the bacteria to grow and multiply.
The full article covers:
- What are antibiotics?
- What do antibiotics treat?
- Do antibiotics treat viral infections?
- What are the side effects of antibiotics?
- Why is it important to take antibiotics only when they're needed?
- How do I use antibiotics correctly?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T36.6X4S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T36.6X4SOverview
What is the ICD-10 code for poisoning by rifampicins, undetermined, sequela?
The ICD-10-CM code for poisoning by rifampicins, undetermined, sequela is T36.6X4S (sometimes written as T366X4S). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is T36.6X4S (Poisoning by rifampicins, undetermined) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by rifampicins, undetermined, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character S in T36.6X4S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by rifampicins, undetermined itself has resolved, not the original event.
What MS-DRG does T36.6X4S group to?
When poisoning by rifampicins, undetermined, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 923, 922, with relative weights from 0.9980 to 1.6248 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T36.6X4S 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 rifampicins, undetermined, sequela on inpatient claims. The code appears in the Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances (T36-T50) range of the CMS exempt list.
