T59.2X1A: Toxic effect of formaldehyde, accidental (unintentional), initial encounter

T59.2X1A, toxic effect of formaldehyde, accidental (unintentional), initial encounter, is listed as a covered diagnosis in 3 Medicare billing and coding articles that apply to 12 HCPCS Level II codes, including G0238 (Therapeutic procedures to improve respiratory function…), G0237 (Therapeutic procedures to increase strength or endurance…), G0239 (Therapeutic procedures to improve respiratory function or…). The articles come from 2 Medicare contractors. A listed diagnosis supports medical necessity only; coverage still depends on the LCD's criteria and on documentation in the medical record.

HCPCS Level II codes with T59.2X1A as a covered diagnosis

Medicare policy articles listing T59.2X1A

• A56717: Billing and Coding: Respiratory Therapy (Respiratory Care) (Palmetto GBA (MAC - Part A); 3 Level II codes). LCD with the same title: L34430
• A57224: Billing and Coding: Respiratory Care (Noridian Healthcare Solutions, LLC (MAC - Part A, MAC - Part B); 3 Level II codes). LCD with the same title: L34149
• A56612: Billing and Coding: CT of the Head (Palmetto GBA (MAC - Part A, MAC - Part B); 9 Level II codes). LCD with the same title: L34417

A diagnosis listed as covered in a billing and coding article supports medical necessity for the article's codes; it does not guarantee payment. Coverage depends on the LCD's criteria, the contractor's jurisdiction and documentation in the medical record.

Other T59 diagnoses (Toxic effect of other gases, fumes and vapors)

• T59.2X2A — Toxic effect of formaldehyde, intentional self-harm, initial encounter
• T59.2X3A — Toxic effect of formaldehyde, assault, initial encounter
• T59.2X4A — Toxic effect of formaldehyde, undetermined, initial encounter
• T59.0X1A — Toxic effect of nitrogen oxides, accidental (unintentional), initial…
• T59.0X2A — Toxic effect of nitrogen oxides, intentional self-harm, initial…
• T59.0X3A — Toxic effect of nitrogen oxides, assault, initial encounter
• T59.0X4A — Toxic effect of nitrogen oxides, undetermined, initial encounter
• T59.1X1A — Toxic effect of sulfur dioxide, accidental (unintentional), initial…
• T59.1X2A — Toxic effect of sulfur dioxide, intentional self-harm, initial…
• T59.1X3A — Toxic effect of sulfur dioxide, assault, initial encounter
• T59.1X4A — Toxic effect of sulfur dioxide, undetermined, initial encounter
• T59.3X1A — Toxic effect of lacrimogenic gas, accidental (unintentional)…
• T59.3X2A — Toxic effect of lacrimogenic gas, intentional self-harm, initial…
• T59.3X3A — Toxic effect of lacrimogenic gas, assault, initial encounter
• T59.3X4A — Toxic effect of lacrimogenic gas, undetermined, initial encounter
• T59.4X1A — Toxic effect of chlorine gas, accidental (unintentional), initial…
• T59.4X2A — Toxic effect of chlorine gas, intentional self-harm, initial encounter
• T59.4X3A — Toxic effect of chlorine gas, assault, initial encounter
• T59.4X4A — Toxic effect of chlorine gas, undetermined, initial encounter
• T59.5X1A — Toxic effect of fluorine gas and hydrogen fluoride, accidental…
• T59.5X2A — Toxic effect of fluorine gas and hydrogen fluoride, intentional…
• T59.5X3A — Toxic effect of fluorine gas and hydrogen fluoride, assault, initial…
• T59.5X4A — Toxic effect of fluorine gas and hydrogen fluoride, undetermined…
• T59.6X1A — Toxic effect of hydrogen sulfide, accidental (unintentional)…
• T59.6X2A — Toxic effect of hydrogen sulfide, intentional self-harm, initial…
• T59.6X3A — Toxic effect of hydrogen sulfide, assault, initial encounter
• T59.6X4A — Toxic effect of hydrogen sulfide, undetermined, initial encounter
• T59.7X1A — Toxic effect of carbon dioxide, accidental (unintentional), initial…
• T59.7X2A — Toxic effect of carbon dioxide, intentional self-harm, initial…
• T59.7X3A — Toxic effect of carbon dioxide, assault, initial encounter

Frequently asked questions

Does Medicare cover T59.2X1A (Toxic effect of formaldehyde, accidental (unintentional)…)?

Medicare covers items and services, not diagnoses. 3 Medicare billing and coding articles list T59.2X1A as a covered diagnosis for 12 HCPCS Level II codes: the diagnosis can support medical necessity for those codes, but payment still depends on the LCD's coverage criteria and the medical record.

Which HCPCS codes can be billed with ICD-10 T59.2X1A?

The Level II codes from the policies most specific to this diagnosis are G0238 (Therapeutic procedures to improve respiratory function…, 2 articles); G0237 (Therapeutic procedures to increase strength or endurance…, 2 articles); G0239 (Therapeutic procedures to improve respiratory function or…, 2 articles); G2187 (Patients with clinical indications for imaging of the…, 1 article); G2188 (Patients with clinical indications for imaging of the…, 1 article). Code choice depends on the item supplied; check each code's descriptor.

Which Medicare policy articles list T59.2X1A?

A56717 (Billing and Coding: Respiratory Therapy (Respiratory Care)); A57224 (Billing and Coding: Respiratory Care); A56612 (Billing and Coding: CT of the Head).

What is ICD-10-CM code T59.2X1A?

T59.2X1A is the ICD-10-CM code for toxic effect of formaldehyde, accidental (unintentional), initial encounter, in category T59 (Toxic effect of other gases, fumes and vapors), chapter 19: Injury, poisoning and other consequences of external causes.

Next steps

• Run a reimbursement report for a device billed under G0238
• Watch G0238 for fee, coverage and descriptor changes
• Build a full Medicare revenue model for G0238

Sources: CMS Medicare Coverage Database billing and coding articles (covered ICD-10 code lists and HCPCS links); ICD-10-CM FY2026; CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule 2026 (non-rural state fees). Not billing or legal advice.

Chapter 19: Injury, poisoning and other consequences of external causes · All diagnoses · HCPCS lookup