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CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

CPT code 88740 denotes a quantitative, transcutaneous measurement of carboxyhemoglobin performed by an analyst to assess carbon monoxide exposure without invasive sampling. Nationally, noninvasive carboxyhemoglobin testing supports timely triage in emergency, occupational, and outpatient settings and can influence decisions about observation or therapy. This code is reported once per day per patient.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for transcutaneous carboxyhemoglobin testing, the typical sites of service where this procedure is delivered, and the operational note that the code is reportable once daily. The publication outlines common billing modifiers associated with this service (input provided), notes where data are unavailable, and identifies areas for coding clarity.

This summary is intended for a national audience of coding professionals, clinical administrators, and policy analysts seeking a clear reference on CPT code 88740, including its clinical purpose, reporting frequency, and payer relevance.

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Billing Code Overview

CPT code 88740 describes a quantitative, transcutaneous procedure performed by an analyst to evaluate carboxyhemoglobin levels through the skin. This service represents a noninvasive measurement technique used to estimate carbon monoxide exposure by assessing carboxyhemoglobin concentration without blood draw.

Service type: Quantitative transcutaneous carboxyhemoglobin measurement
Typical site of service: Outpatient clinics, emergency departments, occupational health clinics, and other point-of-care settings where noninvasive toxicology assessment is indicated

Data not available in the input.

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CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

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Billing Code Overview

Service type: Quantitative transcutaneous carboxyhemoglobin measurement
Typical site of service: Outpatient clinics, emergency departments, occupational health clinics, and other point-of-care settings where noninvasive toxicology assessment is indicated

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 45-year-old firefighter presents to the emergency department after being rescued from a structure fire with potential smoke inhalation. The patient reports headache, nausea, and dizziness. Pulse oximetry is unreliable for detecting carbon monoxide exposure. The clinician orders a transcutaneous carboxyhemoglobin measurement to rapidly quantify carboxyhemoglobin levels and guide decisions about supplemental oxygen versus hyperbaric oxygen therapy. A respiratory therapist or clinical laboratory analyst performs the noninvasive transcutaneous quantitative procedure, documents the measured carboxyhemoglobin value in the medical record, and the result is reported once for that calendar day using 88740. The typical site of service is the emergency department, inpatient hospital unit, or burn center where rapid, repeated noninvasive monitoring may be needed to track response to therapy.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional component of a split-billed service if applicable (rare for transcutaneous measurement).
`52`	Reduced services	Use when the service is partially reduced or not fully performed.
`53`	Discontinued procedure	Use when the measurement was started but terminated due to patient condition.
`59`	Distinct procedural service	Use when a separate, distinct procedure unrelated to other services is performed the same day.
`62`	Two surgeons	Use when two surgeons share responsibility for a procedure (unlikely but included among common modifiers).
`90`	Reference (Outside) laboratory	Use when the test was performed by an outside laboratory and only reference lab reporting applies.
`TC`	Technical component	Use when billing only the technical component of the measurement (equipment/technician).
`91`	Repeat clinical diagnostic test (Not in provided list)	Data not available in the input.
`QX`	Modifier for ordering/servicing practitioner relationship	Use in applicable Medicare Advantage or contractor-specific situations when applicable credentials require modifier reporting.
`XU`	Unusual non-overlapping service	Use when the procedure is distinct and not overlapping other billed services.

Taxonomy Code	Specialty	Notes
207Q00000X	Emergency Medicine	ED physicians commonly order and interpret transcutaneous carboxyhemoglobin measurements.
207RC0000X	Anesthesiology	Anesthesiologists may use carboxyhemoglobin monitoring in perioperative or critical care settings.
207L00000X	Pulmonary Disease	Pulmonologists manage smoke inhalation and CO exposure and interpret serial measurements.
3336C0000X	Clinical Laboratory	Clinical laboratory technicians/analysts perform and report quantitative transcutaneous measurements.
363A00000X	Respiratory Care	Respiratory therapists perform noninvasive monitoring and document values.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`T58.XXA`	Toxic effect of carbon monoxide, accidental, initial encounter	Direct diagnosis indicating carbon monoxide exposure prompting carboxyhemoglobin measurement.
`T58.XXD`	Toxic effect of carbon monoxide, accidental, subsequent encounter	Used for follow-up encounters where repeat measurement may be performed.
`T58.XXS`	Toxic effect of carbon monoxide, accidental, sequela	Used for late effects; measurement may be part of evaluation of persistent symptoms.
`T59.8XXA`	Toxic effect of other gases, fumes and vapors, initial encounter	Applied when smoke or mixed inhalation exposures are suspected and screening for CO is indicated.
`J68.0`	Bronchitis and pneumonitis due to chemicals, gases, fumes and vapors	Relevant when inhalation injury from smoke accompanies CO exposure; clinicians may measure carboxyhemoglobin to assess contribution of CO to respiratory compromise.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`94760`	Noninvasive ear or pulse oximetry for oxygen saturation (per encounter)	Often performed concurrently to assess oxygenation though pulse oximetry cannot detect carboxyhemoglobin; used for complementary monitoring.
`94799`	Unlisted pulmonary service or procedure	May be reported when a specific device or method for transcutaneous measurement lacks a dedicated code (use only when appropriate).
`36415`	Collection of venous blood by venipuncture	Performed if a venous blood sample is obtained for laboratory carboxyhemoglobin by blood gas or co-oximetry as a confirmatory test.
`82803`	Carboxyhemoglobin test, blood (quantitative)	Laboratory measurement of carboxyhemoglobin from blood sample used to confirm and quantify CO exposure; complements transcutaneous `88740`.
`99000`	Handling and/or conveyance of specimen for transfer to another facility (if applicable)	Used when specimen transfer is needed for reference lab testing that complements transcutaneous measurement.

CPT 88720: Noninvasive Bilirubin Measurement, Technical Assay

CPT-88738-TRANSCUTANEOUS-HEMOGLOBIN-MEASUREMENT

CPT 88738: Transcutaneous Hemoglobin Measurement

CPT-88741-TRANSCUTANEOUS-METHEMOGLOBIN-MEASUREMENT

CPT 88741: Transcutaneous Quantitative Methemoglobin Measurement

CPT-88749-UNLISTED-IN-VIVO-LABORATORY-SERVICE

CPT 88749: Unlisted In Vivo Laboratory Service

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional component of a split-billed service if applicable (rare for transcutaneous measurement).
`52`	Reduced services	Use when the service is partially reduced or not fully performed.
`53`	Discontinued procedure	Use when the measurement was started but terminated due to patient condition.
`59`	Distinct procedural service	Use when a separate, distinct procedure unrelated to other services is performed the same day.
`62`	Two surgeons	Use when two surgeons share responsibility for a procedure (unlikely but included among common modifiers).
`90`	Reference (Outside) laboratory	Use when the test was performed by an outside laboratory and only reference lab reporting applies.
`TC`	Technical component	Use when billing only the technical component of the measurement (equipment/technician).
`91`	Repeat clinical diagnostic test (Not in provided list)	Data not available in the input.
`QX`	Modifier for ordering/servicing practitioner relationship	Use in applicable Medicare Advantage or contractor-specific situations when applicable credentials require modifier reporting.
`XU`	Unusual non-overlapping service	Use when the procedure is distinct and not overlapping other billed services.

Taxonomy Code	Specialty	Notes
207Q00000X	Emergency Medicine	ED physicians commonly order and interpret transcutaneous carboxyhemoglobin measurements.
207RC0000X	Anesthesiology	Anesthesiologists may use carboxyhemoglobin monitoring in perioperative or critical care settings.
207L00000X	Pulmonary Disease	Pulmonologists manage smoke inhalation and CO exposure and interpret serial measurements.
3336C0000X	Clinical Laboratory	Clinical laboratory technicians/analysts perform and report quantitative transcutaneous measurements.
363A00000X	Respiratory Care	Respiratory therapists perform noninvasive monitoring and document values.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`T58.XXA`	Toxic effect of carbon monoxide, accidental, initial encounter	Direct diagnosis indicating carbon monoxide exposure prompting carboxyhemoglobin measurement.
`T58.XXD`	Toxic effect of carbon monoxide, accidental, subsequent encounter	Used for follow-up encounters where repeat measurement may be performed.
`T58.XXS`	Toxic effect of carbon monoxide, accidental, sequela	Used for late effects; measurement may be part of evaluation of persistent symptoms.
`T59.8XXA`	Toxic effect of other gases, fumes and vapors, initial encounter	Applied when smoke or mixed inhalation exposures are suspected and screening for CO is indicated.
`J68.0`	Bronchitis and pneumonitis due to chemicals, gases, fumes and vapors	Relevant when inhalation injury from smoke accompanies CO exposure; clinicians may measure carboxyhemoglobin to assess contribution of CO to respiratory compromise.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`94760`	Noninvasive ear or pulse oximetry for oxygen saturation (per encounter)	Often performed concurrently to assess oxygenation though pulse oximetry cannot detect carboxyhemoglobin; used for complementary monitoring.
`94799`	Unlisted pulmonary service or procedure	May be reported when a specific device or method for transcutaneous measurement lacks a dedicated code (use only when appropriate).
`36415`	Collection of venous blood by venipuncture	Performed if a venous blood sample is obtained for laboratory carboxyhemoglobin by blood gas or co-oximetry as a confirmatory test.
`82803`	Carboxyhemoglobin test, blood (quantitative)	Laboratory measurement of carboxyhemoglobin from blood sample used to confirm and quantify CO exposure; complements transcutaneous `88740`.
`99000`	Handling and/or conveyance of specimen for transfer to another facility (if applicable)	Used when specimen transfer is needed for reference lab testing that complements transcutaneous measurement.

CPT 88720: Noninvasive Bilirubin Measurement, Technical Assay

CPT-88738-TRANSCUTANEOUS-HEMOGLOBIN-MEASUREMENT

CPT 88738: Transcutaneous Hemoglobin Measurement

CPT-88741-TRANSCUTANEOUS-METHEMOGLOBIN-MEASUREMENT

CPT 88741: Transcutaneous Quantitative Methemoglobin Measurement

CPT-88749-UNLISTED-IN-VIVO-LABORATORY-SERVICE

CPT 88749: Unlisted In Vivo Laboratory Service

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

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CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

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Billing Code Overview

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CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

Sign up for cpt 88740 policy alerts

Billing Code Overview

CPT 88740: Transcutaneous Quantitative Carboxyhemoglobin Measurement

Sign up for cpt 88740 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 88740 represent and where is it typically performed?

How often can CPT 88740 be billed for a patient in a single day?

Which other CPT codes are commonly reported with or related to CPT 88740?

Which billing modifiers are commonly noted as relevant for reporting CPT 88740?

Which specialties or provider types are associated with ordering, performing, or interpreting CPT 88740?

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 88740 represent and where is it typically performed?

How often can CPT 88740 be billed for a patient in a single day?

Which other CPT codes are commonly reported with or related to CPT 88740?

Which billing modifiers are commonly noted as relevant for reporting CPT 88740?

Which specialties or provider types are associated with ordering, performing, or interpreting CPT 88740?

References