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ICD-10-CM 2027 diagnosis code

X30.XXXAExposure to excessive natural heat, initial encounter

✓ Billable / specificPOA exemptRequires 7th character

X30.XXXA is a valid, billable ICD-10-CM code for exposure to excessive natural heat, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About X30.XXXA

X30.XXXA is the ICD-10-CM diagnosis code for exposure to excessive natural heat, initial encounter. It belongs to category X30 (exposure to excessive natural heat), block X30-X39 (exposure to forces of nature) and chapter 20 (external causes of morbidity). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as E900.0 (accident caused by excessive heat due to weather conditions).

7th character

Ainitial encounter

Other encounter types for X30:

Notes that apply from higher levels

Instructions written at a parent level also apply to X30.XXXA.

› From X30 Exposure to excessive natural heat
Excludes1
  • excessive heat of man-made origin (W92)
  • exposure to man-made radiation (W89)
  • exposure to sunlight (X32)
  • exposure to tanning bed (W89)

Broader instructions also apply from Chapter 20: External causes of morbidity.

ICD-9-CM equivalent

Converter →
  • E900.0Accident caused by excessive heat due to weather conditionsapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about X30.XXXA

Is X30.XXXA billable?

Yes. X30.XXXA is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

What does the "A" at the end of X30.XXXA mean?

It is the 7th character for initial encounter. Per the official guidelines, use it while the patient is receiving active treatment for the condition.

Can X30.XXXA be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict X30.XXXA as a principal diagnosis.

Is X30.XXXA a CC or MCC?

No. X30.XXXA is neither a CC nor an MCC under MS-DRG v44.0.

What is the ICD-9 code for X30.XXXA?

The CMS General Equivalence Mappings map X30.XXXA to ICD-9-CM E900.0.