ICD-10-CM 2027 diagnosis code
T33.522ASuperficial frostbite of left hand, initial encounter
T33.522A is a valid, billable ICD-10-CM code for superficial frostbite of left hand, 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 T33.522A
T33.522A is the ICD-10-CM diagnosis code for superficial frostbite of left hand, initial encounter. It belongs to category T33 (superficial frostbite), block T33-T34 (frostbite) and chapter 19 (injury, poisoning and certain other consequences of external causes). 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.
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 922 (Other Injury, Poisoning and Toxic Effect Diagnoses with MCC, relative weight 1.6238) and DRG 923 (Other Injury, Poisoning and Toxic Effect Diagnoses without MCC, relative weight 0.9973), in MDC 21 (Injuries, Poisonings and Toxic Effects of Drugs), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
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 991.1 (frostbite of hand).
7th character
Ainitial encounter
CC/MCC status for this injury by encounter: CC for A; Neither CC nor MCC for D, S.
Other encounter types for T33.522:
Notes that apply from higher levels
Instructions written at a parent level also apply to T33.522A.
› From T33.52 Superficial frostbite of hand
- superficial frostbite of fingers (T33.53-)
› From T33 Superficial frostbite
- frostbite with partial thickness skin loss
Broader instructions also apply from T33-T34 Frostbite and Chapter 19: Injury, poisoning and certain other consequences of external causes.
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 21 · Injuries, Poisonings and Toxic Effects of Drugs
ICD-9-CM equivalent
Converter →- 991.1Frostbite of handapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about T33.522A
Is T33.522A billable?
- Yes. T33.522A 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 T33.522A 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 T33.522A be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict T33.522A as a principal diagnosis.
Is T33.522A a CC or MCC?
- T33.522A is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does T33.522A group to?
- T33.522A is used in the MS-DRG v44.0 logic for MS-DRG 922 (Other Injury, Poisoning and Toxic Effect Diagnoses with MCC) and MS-DRG 923 (Other Injury, Poisoning and Toxic Effect Diagnoses without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for T33.522A?
- The CMS General Equivalence Mappings map T33.522A to ICD-9-CM 991.1.