2026 ICD-10-CM Diagnosis Code T70.29XSOther effects of high altitude, sequela
T70.29XS is a billable ICD-10-CM diagnosis code for other effects of high altitude, 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 Effect of other external causes, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T70.29XS 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.
- Acute mountain sickness
- Aerodontalgia
- Anoxia caused by high altitude
- Barotrauma
- Barotrauma of ascent
- Barotrauma of descent
- Chronic mountain sickness
- Decompression sickness type II
- Ebullism
- Effects of air pressure
- Effects of high altitude
- Erythrocytosis caused by low atmospheric pressure
- Erythrocytosis due to tissue hypoxemia
- Finding of sensation of tooth
- Gastrointestinal barotrauma
- Headache caused by high altitude
- High altitude pulmonary edema
- High altitude retinopathy
- Local pressure effects
- Pulmonary barotrauma
- Pulmonary hypertension caused by low air pressure due to chronic exposure to high altitude
- Pulmonary hypertension due to lung disease and/or hypoxia
- Subacute mountain sickness
- Toothache
- Visceral decompression injury
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Effects of air pressure and water pressure (T70). 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
Barotrauma
injury following pressure changes; includes injury to the eustachian tube, ear drum, lung and stomach.Toothache
pain in the adjacent areas of the teeth.Grade 2 Toothache, CTCAE|Grade 2 Toothache
moderate pain; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)Grade 3 Toothache, CTCAE|Grade 3 Toothache
severe pain; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)Grade 1 Toothache, CTCAE|Grade 1 Toothache
mild painGrade 2 Toothache, CTCAE|Grade 2 Toothache
moderate pain; limiting instrumental adlGrade 3 Toothache, CTCAE|Grade 3 Toothache
severe pain; limiting self care adlToothache
a painful sensation originating from a tooth.Toothache, CTCAE|Toothache|Toothache
a disorder characterized by a sensation of marked discomfort in the tooth.
Patient EducationClinical
Barotrauma
Barotrauma means injury to your body because of changes in barometric (air) or water pressure. One common type happens to your ear. A change in altitude may cause your ears to hurt. This can happen if you are flying in an airplane, driving in the mountains, or scuba diving.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T70.29XS to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T70.29XSOverview
Is T70.29XS (Other effects of high altitude) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other effects of high altitude, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T70.29XS mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the other effects of high altitude itself has resolved, not the original event.
What MS-DRG does T70.29XS group to?
When other effects of high altitude, 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 T70.29XS 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 other effects of high altitude, sequela on inpatient claims.
What is the ICD-9 equivalent of T70.29XS?
Under the General Equivalence Mappings, other effects of high altitude, sequela converts to ICD-9-CM 909.4 (late eff cert ext cause). 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.
