CPT 82375: Carboxyhemoglobin Measurement

CPT code 82375 designates a laboratory measurement of carboxyhemoglobin, the hemoglobin–carbon monoxide complex used to detect and quantify carbon monoxide exposure. The test is clinically important for diagnosing acute and chronic carbon monoxide poisoning, guiding acute care decisions in emergency and inpatient settings, and supporting occupational and public health surveillance. Nationally, timely measurement of carboxyhemoglobin informs patient triage and hyperbaric oxygen consideration and is a critical component of toxicology testing panels.

Key payers referenced include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, typical sites of service, and payer relevance for CPT code 82375. The publication covers expected use cases, common billing modifiers (listed separately), and where this test fits within laboratory service lines. It also outlines benchmarking and policy considerations affecting coverage and utilization without prescribing clinical actions.

This summary is intended for health policy analysts, clinical laboratory managers, billing professionals, and payer contracting teams seeking a focused, national-level briefing on CPT code 82375 and its role in carbon monoxide exposure assessment.

Billing Code Overview

CPT code 82375 measures carboxyhemoglobin, the complex formed when carbon monoxide binds to hemoglobin. This laboratory test quantifies the proportion of hemoglobin bound to carbon monoxide and is used to assess exposure to carbon monoxide, a colorless, odorless, and potentially lethal gas produced by combustion of fuels.

Service type: Laboratory diagnostic assay for toxicology exposure assessment

Typical site of service: Clinical laboratory or hospital laboratory (emergency department and inpatient settings for suspected acute exposure)

Clinical Context

A typical patient is an adult presenting to the emergency department or urgent care after suspected carbon monoxide (CO) exposure from smoke inhalation, faulty heating, or vehicle exhaust. The patient may have headache, dizziness, nausea, confusion, syncope, or unexplained hypoxemia. Initial evaluation includes history, pulse oximetry (which may be falsely normal), and triage assessment. A blood sample (venous or arterial) is collected and sent to the laboratory for measurement of carboxyhemoglobin using spectrophotometric or co-oximetry methods. The lab analyst performs 82375 to quantify the percentage of hemoglobin bound to carbon monoxide. Results are returned to the treating clinician to confirm CO exposure, guide supplemental oxygen therapy or hyperbaric oxygen consideration, and document occupational or public health reporting when indicated. Typical sites of service include emergency departments, urgent care centers, inpatient hospital wards, occupational health clinics, and reference laboratories.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the physician interpretation/report portion if separated from the technical lab component.
`TC`

Taxonomy Code	Specialty	Notes
207Q00000X	Emergency Medicine	ED physicians who order and interpret COHb results in acute exposures.
208000000X	Pathology & Laboratory Medicine	Laboratory directors and pathologists overseeing test validation and reporting.
207L00000X	Occupational Medicine	Clinicians evaluating workplace CO exposures and fitness-for-duty decisions.
2084P0800X	Toxicology	Medical toxicologists consulted for management of significant CO poisoning.
261QM0800X	Critical Care Medicine	Intensivists managing severe CO poisoning requiring hyperbaric therapy or ICU care.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`T58.0X1A`	Toxic effect of carbon monoxide, accidental, initial encounter	Direct diagnosis for acute accidental CO poisoning prompting `82375` testing.
`T58.0X2A`	Toxic effect of carbon monoxide, intentional self-harm, initial encounter	Used when CO exposure is self-inflicted; lab confirmation via `82375` may be needed.
`T58.0X3A`	Toxic effect of carbon monoxide, assault, initial encounter	Applied for CO exposure due to assault; `82375` documents exposure level.
`T58.0X4A`	Toxic effect of carbon monoxide, undetermined, initial encounter	Used when intent is unclear; lab measurement supports diagnosis and management.
`R53.1`	Weakness	Symptom commonly prompting evaluation for CO exposure and `82375` testing.
`R51`	Headache	Frequent presenting symptom in CO exposure; often triggers measurement of carboxyhemoglobin.
`R40.0`	Somnolence	Altered mental status may be present with CO poisoning and necessitates `82375` testing.
`Z20.828`	Contact with and (suspected) exposure to other viral communicable diseases	Data not directly related; include only clinically relevant codes above.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous blood draw commonly used to obtain specimen for `82375` testing.
`82803`	Blood gases, pH, and electrolytes, blood, any number of determinations	Often ordered concurrently to assess oxygenation and acid-base status in suspected CO exposure.
`94760`	Noninvasive ear or pulse oximetry for oxygen saturation; single determination	Pulse oximetry is performed in triage but can be falsely normal in CO poisoning; often documented alongside `82375`.
`94770`	Pulse oximetry; multiple determinations	Serial oxygen saturation checks during treatment and monitoring.
`99000`	Handling and/or conveyance of specimen for transfer from physician's office to lab (if applicable)	Used when specimen transport or handling charges are billed in outpatient or clinic settings.

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Summary & Overview