2027 ICD-10-CM Diagnosis Code T18.4XXAForeign body in colon, initial encounter
T18.4XXA is a billable ICD-10-CM diagnosis code for foreign body in colon, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of foreign body entering opening, initial encounter; External cause codes: intent of injury, accidental/unintentional; and External cause codes: other specified, classifiable and NEC; initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Foreign body in appendix
- Foreign body in ascending colon
- Foreign body in cecum
- Foreign body in colon
- Foreign body in descending colon
- Foreign body in intestine and colon
- Foreign body in sigmoid colon
- Foreign body in transverse colon
- Foreign body of large intestine
- Impaction of intestine
- Impaction of large intestine
- Impaction of large intestine due to foreign body
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Foreign body in alimentary tract (T18). 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 T18.4XXA: its own notes plus those printed at T18, block T15-T19, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code, if known, for foreign body entering into or through a natural orifice (W44.-)
- 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 T18
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name T18.4XXA, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming T18.4XXA: its condition is not part of those codes, and both may be reported when the patient has both.
- Z03.82 Encounter for observation for suspected foreign body ruled outforeign body in alimentary tract (T18) names T18, which includes this code
- Block S30-S39 Injuries to the abdomen, lower back, lumbar spine, pelvis and external genitals
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index; each main term links to its index entry.
- Aspiration
- food (any type) (into respiratory tract) (with asphyxia, obstruction respiratory tract, suffocation)
- Choked, choking (on) (any object except food or vomitus)
- food (bone) (seed)
- Compression
- trachea by
- food (lodged in esophagus)
- Food (any type) in
- air passages (with asphyxia, obstruction, or suffocation)
- Food (any type) in
- alimentary tract causing asphyxia (due to compression of trachea)
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Foreign Bodies
If you've ever gotten a splinter or had sand in your eye, you've had experience with a foreign body. A foreign body is something that is stuck inside you but isn't supposed to be there. You may inhale or swallow a foreign body, or you may get one from an injury to almost any part of your body.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T18.4XXA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T18.4XXAOverview
What is the ICD-10 code for foreign body in colon, initial encounter?
The ICD-10-CM code for foreign body in colon, initial encounter is T18.4XXA (sometimes written as T184XXA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is T18.4XXA (Foreign body in colon) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report foreign body in colon, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in T18.4XXA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for foreign body in colon, such as an emergency visit or first evaluation.
What MS-DRG does T18.4XXA group to?
When foreign body in colon, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 394, 395, 393, with relative weights from 0.6379 to 1.5877 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of T18.4XXA?
Under the General Equivalence Mappings, foreign body in colon, initial encounter converts to ICD-9-CM 936 (FB in intestine & colon) and E915 (FB entering oth orifice). The mapping is approximate, so confirm the match fits the documentation.
