Summary & Overview

CPT 82376: Carboxyhemoglobin (Carbon Monoxide) Testing

CPT code 82376 identifies laboratory testing to detect carboxyhemoglobin or carbon monoxide exposure, a critical diagnostic step in suspected carbon monoxide poisoning. Carbon monoxide is a leading cause of fatal poisoning nationally; timely measurement of carboxyhemoglobin informs clinical decisions such as oxygen therapy and hyperbaric oxygen referral. The code represents a standard laboratory toxicology service used across emergency departments, inpatient settings, and clinical laboratories.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for use of the test, typical sites of service, common billing considerations, and national-level benchmarks where available. The publication also highlights payer coverage patterns and coding nuances relevant to hospitals and clinical labs.

This executive summary orients clinicians, billing staff, and policy analysts to the purpose and clinical importance of CPT code 82376, outlines what to expect from payer coverage discussions, and summarizes the operational contexts in which the test is performed. Data not available in the input are noted where applicable in detailed sections.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare82376CPTtoxicologycarboxyhemoglobincarbon-monoxidelaboratoryemergency-medicineclinical-testing

Billing Code Overview

CPT code 82376 describes laboratory testing to detect carboxyhemoglobin or carbon monoxide exposure. The service is a blood-based toxicology analysis performed by a laboratory analyst to determine whether carbon monoxide, a poisonous, colorless, odorless gas, is present.

Service type: Laboratory toxicology testing for carboxyhemoglobin/carbon monoxide levels
Typical site of service: Clinical laboratory or hospital laboratory; testing may be ordered in emergency departments or inpatient settings when carbon monoxide exposure or poisoning is suspected

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult who presents to the emergency department or urgent care with symptoms suggestive of carbon monoxide exposure — headache, dizziness, nausea, confusion, syncope, flu-like symptoms without fever, or history of exposure to smoke or exhaust in an enclosed space. Prehospital providers, family members, or the patient report potential exposure to combustion fumes, a faulty heater, or house fire. Initial evaluation includes vital signs, pulse oximetry (which can be falsely normal), and a focused history of exposure. The clinical workflow: triage flags potential poisoning, the treating clinician orders a blood sample for carboxyhemoglobin testing (82376) processed by the hospital laboratory using co-oximetry or specialized assays. Results guide management decisions: removal from exposure, administration of 100% oxygen via non-rebreather mask, hyperbaric oxygen consideration, and admission or discharge. Typical sites of service are emergency departments, inpatient hospital labs, urgent care centers, and outpatient hospital-based laboratories. The service is performed by laboratory personnel with medical direction from pathologists or clinical chemists and reported by the facility lab using the 82376 code to document testing for carboxyhemoglobin/carbon monoxide.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the physician/pathologist professional interpretation component separate from the facility technical component.
`TC`	Technical component	Use when billing only the laboratory/facility technical component of the test.
`90`	Reference (outside) lab	Use when the specimen is sent to an outside laboratory for testing and that lab performs the service.
`91`	Repeat clinical diagnostic test	Use when the same test is repeated on the same day to monitor changing levels.
`59`	Distinct procedural service	Use when this test is distinct and separate from other services on the same day (if applicable under payer rules).
`52`	Reduced services	Use when the test is partially performed or limited for clinical reasons.
`53`	Discontinued procedure	Use when specimen collection or testing was started but discontinued due to patient condition.
`23`	Unusual anesthesia	Rarely applicable; use if unusual anesthesia circumstances impacted testing logistics (limited applicability).
`90`	Reference (outside) lab	(Included for clarity: distinguishes outside lab billing)
`91`	Repeat test	(Included for emphasis on monitoring use)

Taxonomy Code	Specialty	Notes
207K00000X	Pathology	Clinical pathologists direct laboratory testing and interpretation.
362X00000X	Emergency Medicine	Emergency physicians frequently order and act on `82376` results.
208000000X	Family Medicine	Primary care and urgent care clinicians may order testing after suspected exposure.
207L00000X	Anatomic and Clinical Pathology	Laboratory medicine specialists overseeing toxicology and co-oximetry.
2086S0121X	Internal Medicine	Hospitalists and internists manage inpatient patients with elevated carboxyhemoglobin.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`T58.XXA`	Toxic effect of carbon monoxide, accidental, initial encounter	Direct diagnosis indicating CO poisoning; primary reason to order `82376`.
`T58.XXD`	Toxic effect of carbon monoxide, accidental, subsequent encounter	Used for follow-up care after initial exposure and repeated testing.
`T58.XXS`	Toxic effect of carbon monoxide, accidental, sequela	Used when long-term sequelae from CO poisoning are being managed.
`T58.2X1A`	Toxic effect of carbon monoxide from occupation, initial encounter	Occupational exposure settings where `82376` is indicated.
`X47.XXXA`	Accidental poisoning by and exposure to other gases and vapors, initial encounter	Alternative external cause coding accompanying CO poisoning evaluations.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Often performed immediately prior to `82376` to obtain the blood specimen for carboxyhemoglobin testing.
`85025`	Blood count for platelet function; automated platelet count (CBC automated)	Frequently ordered concurrently to evaluate overall clinical status in intoxicated or ill patients.
`94760`	Noninvasive ear or pulse oximetry for oxygen saturation	Pulse oximetry is done alongside but may be falsely normal in CO poisoning; documents oxygenation status.
`97799`	Unlisted physical medicine/rehabilitation service	Not typically used; include only if specific monitoring or treatment services for CO sequelae are billed under unlisted codes.
`99183`	Physician attendance and supervision for hyperbaric oxygen therapy, per course	Hyperbaric oxygen therapy is a potential next-step treatment for significant CO poisoning and may follow positive `82376` results.