2026 ICD-10-CM Diagnosis Code S21.90XDUnspecified open wound of unspecified part of thorax, subsequent encounter
S21.90XD is a billable ICD-10-CM diagnosis code for unspecified open wound of unspecified part of thorax, subsequent encounter. The 7th character D marks it as a subsequent encounter code, used during routine care in the healing or recovery phase. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, subsequent encounter.
Code Identity
Code Classification
Present on Admission (POA)Billing
S21.90XD 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 lung injury
- Anterior cord syndrome due to open fracture of T1-T6 level
- Burst fracture of thoracic vertebra
- Central cord syndrome of thoracic spinal cord due to injury of spinal cord at T7 - T12 level
- Central cord syndrome of thoracic spinal cord due to open fracture at T1-T6 level
- Central cord syndrome of thoracic spinal cord due to open fracture at T7-T12 level
- Central cord syndrome of thoracic spinal cord due to traumatic injury
- Closed injury of lung
- Complete spinal cord injury at T1-T6 level
- Complete spinal cord injury at T7-T12 level
- Contusion of lung
- Contusion of lung with open wound into thorax
- Contusion to heart
- Contusion to heart with open wound into thorax
- Direct acute lung injury
- Dislocation of costovertebral joint
- Extravasation injury
- Fracture of eight OR more ribs
- Fracture of five ribs
- Fracture of four ribs
- Fracture of multiple left ribs
- Fracture of multiple right ribs
- Fracture of one rib
- Fracture of seven ribs
- Fracture of six ribs
- Fracture of spinous process of thoracic vertebra
- Fracture of three ribs
- Fracture of transverse process of thoracic vertebra
- Fracture of two ribs
- Fractures involving thorax with lower back and pelvis
- Fractures involving thorax with lower back and pelvis with limb
- Glass in chest
- Glass in trunk
- Heart injury, closed
- Heart injury, open
- Heart laceration with open wound into thorax, with penetration of heart chambers
- Hemopericardium
- Hemopneumothorax
- Hemothorax
- Injury of bronchus with open wound into thoracic cavity
- Injury of cutaneous sensory nerve of upper limb
- Injury of diaphragm with open wound into cavity
- Injury of esophagus with open wound into thoracic cavity
- Injury of heart with hemopericardium
- Injury of heart with open wound into thorax
- Injury of intercostobrachial nerve
- Injury of lung with open wound into thorax
- Injury of pleura
- Injury of subclavian artery
- Injury of subclavian vein
- Injury of thoracic cavity
- Injury of thoracic duct
- Injury of thoracic trachea
- Injury of thymus gland
- Laceration of heart
- Laceration of heart with penetration of heart chambers
- Laceration of lung
- Long thoracic nerve injury
- Long thoracic nerve lesion
- Lung laceration with open wound into thorax
- Multiple fractures of upper limb with sternum
- Multiple injuries of intrathoracic organs
- Multiple injuries of thorax
- Multiple intrathoracic organ injury with open wound into cavity
- Multiple open wounds of thoracic wall
- Open bilateral fracture of multiple ribs
- Open division of ligament of thoracic vertebral column
- Open division, chondrosternal ligament
- Open division, costal cartilage ligament
- Open division, rib ligament
- Open division, sternal ligament
- Open fracture involving thorax with lower back and pelvis and limbs
- Open fracture of bone of thorax
- Open fracture of eight OR more ribs
- Open fracture of five ribs
- Open fracture of four ribs
- Open fracture of multiple left ribs
- Open fracture of multiple ribs
- Open fracture of multiple right ribs
- Open fracture of one left rib
- Open fracture of one rib
- Open fracture of one right rib
- Open fracture of seven ribs
- Open fracture of six ribs
- Open fracture of T1-T6 level with spinal cord injury
- Open fracture of T7-T12 level with incomplete spinal cord lesion
- Open fracture of T7-T12 level with spinal cord injury
- Open fracture of three ribs
- Open fracture of two ribs
- Open fracture thoracic vertebra
- Open fracture thoracic vertebra, burst
- Open fracture thoracic vertebra, posterior arch
- Open fracture thoracic vertebra, spinous process
- Open fracture thoracic vertebra, spondylolysis
- Open fracture thoracic vertebra, transverse process
- Open fracture thoracic vertebra, tricolumnar
- Open fracture thoracic vertebra, wedge
- Open heart injury with hemopericardium
- Open injury of bronchus
- Open injury of diaphragm
- Open injury of intercostobrachial nerve
- Open injury of lung
- Open injury of pleura
- Open injury of thoracic duct
- Open injury of thoracic trachea
- Open injury of thymus
- Open injury, long thoracic nerve
- Open injury, subclavian artery
- Open injury, subclavian vein
- Open multiple fracture of thoracic spine
- Open multiple fractures of upper limb with sternum
- Open spinal fracture with anterior thoracic cord lesion, T1-6
- Open spinal fracture with complete thoracic cord lesion, T1-6
- Open spinal fracture with complete thoracic cord lesion, T7-12
- Open spinal fracture with posterior thoracic cord lesion, T1-6
- Open spinal fracture with posterior thoracic cord lesion, T7-12
- Open traumatic dislocation costovertebral joint
- Open traumatic dislocation of costochondral joint
- Open traumatic subluxation costovertebral joint
- Open traumatic subluxation of costochondral joint
- Open wound of thorax
- Open wound of trachea
- Open wounds involving thorax with abdomen, lower back and pelvis
- Penetrating wound of lung
- Posterior cord syndrome due to open fracture of T1-T6 level
- Posterior cord syndrome due to open fracture of T7-T12 level
- Spondylolysis of thoracic vertebra
- Subluxation of costochondral joint
- Subluxation of costovertebral joint
- Three column fracture of thoracic vertebra
- Traumatic anterior cord syndrome
- Traumatic hemopericardium
- Traumatic hemothorax
- Traumatic hemothorax with open wound into thorax
- Traumatic pneumohemothorax
- Traumatic pneumohemothorax with open wound into thorax
- Traumatic pneumothorax
- Traumatic pneumothorax with open wound into thorax
- Wedge fracture of thoracic vertebra
- Wedge fracture of vertebra
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Open wound of thorax (S21). 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
Hemopneumothorax
collection of air and blood in the pleural cavity.Acute Lung Injury
a condition of lung damage that is characterized by bilateral pulmonary infiltrates (pulmonary edema) rich in neutrophils, and in the absence of clinical heart failure. this can represent a spectrum of pulmonary lesions, endothelial and epithelial, due to numerous factors (physical, chemical, or biological).Transfusion-Related Acute Lung Injury
a rare but serious transfusion-related reaction in which fluid builds up in the lungs unrelated to excessively high infusion rate and/or volume (transfusion-associated circulatory overload). signs of transfusion-related acute lung injury include pulmonary secretions; hypotension; fever; dyspnea; tachypnea; tachycardia; and cyanosis.Hemothorax
hemorrhage within the pleural cavity.Hemopericardium
an accumulation of blood within the pericardial sac.
Patient EducationClinical
Chest Injuries and Disorders
The chest is the part of your body between your neck and your abdomen (belly). The medical term for your chest is thorax.
The full article covers:
- What is the chest?
- What are chest injuries and disorders?
- How are chest injuries and disorders diagnosed?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S21.90XD to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S21.90XDOverview
Is S21.90XD (Unspecified open wound of unspecified part of thorax) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of unspecified part of thorax, subsequent encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character D in S21.90XD mean?
The final character D marks a subsequent encounter: use it for routine care while the unspecified open wound of unspecified part of thorax is healing, after active treatment has ended.
What MS-DRG does S21.90XD group to?
When unspecified open wound of unspecified part of thorax, subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 949, 950, with relative weights from 0.6277 to 1.1897 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S21.90XD 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 unspecified open wound of unspecified part of thorax, subsequent encounter on inpatient claims.
What is the ICD-9 equivalent of S21.90XD?
Under the General Equivalence Mappings, unspecified open wound of unspecified part of thorax, subsequent encounter converts to ICD-9-CM V58.89 (other specfied aftercare). 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.
