Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilot© Copyright 2026 American Medical Association. All rights reserved.
A laboratory test known as the carboxyhemoglobin (COHb) quantitative test is conducted to determine the levels of carboxyhemoglobin in the blood. Carboxyhemoglobin is a stable compound formed when carbon monoxide binds with hemoglobin in red blood cells (RBCs). This binding process is significant because it reduces the blood's ability to carry oxygen, which is essential for the proper functioning of vital organs. In normal circumstances, trace amounts of carboxyhemoglobin can be detected in all blood samples; however, individuals who smoke typically exhibit elevated baseline levels due to the inhalation of carbon monoxide from tobacco smoke. The presence of carbon monoxide in the bloodstream can lead to serious health issues, particularly in cases of carbon monoxide or methylene chloride poisoning, as it interferes with the oxygenation of tissues. To perform this test, a blood sample is collected, which can be obtained through various methods such as venipuncture, heelstick, or arterial blood draw. The quantitative measurement of COHb levels is then conducted using a technique called spectrophotometry, which allows for precise analysis of the blood sample to assess the extent of carbon monoxide exposure.
© Copyright 2026 Coding Ahead. All rights reserved.
The carboxyhemoglobin quantitative test is indicated for the following conditions:
The procedure for conducting the carboxyhemoglobin quantitative test involves several key steps to ensure accurate measurement of COHb levels in the blood.
After the carboxyhemoglobin quantitative test is completed, the blood sample is processed in the laboratory, and results are typically available within a specified timeframe. Patients may experience minor discomfort or bruising at the site of the blood draw, but no extensive post-procedure care is usually required. It is important for healthcare providers to interpret the results in conjunction with the patient's clinical history and symptoms, especially in cases of suspected poisoning. Follow-up care may be necessary depending on the test results and the patient's condition, particularly if elevated COHb levels indicate significant carbon monoxide exposure.
| Short Descr | ASSAY CARBOXYHB QUANT | Medium Descr | CARBOXYHEMOGLOBIN QUANTITATIVE | Long Descr | Carboxyhemoglobin; quantitative | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | No | APC Status Indicator | Conditionally packaged laboratory tests | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1H - Lab tests - other (non-Medicare fee schedule) | MUE | 1 | CCS Clinical Classification | 233 - Laboratory - Chemistry and Hematology |
| 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | 91 | Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient. | GZ | Item or service expected to be denied as not reasonable and necessary | GW | Service not related to the hospice patient's terminal condition | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | PN | Non-excepted service provided at an off-campus, outpatient, provider-based department of a hospital | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2011-01-01 | Changed | Short description changed. |
| 2009-01-01 | Changed | Code description changed |
| 2008-01-01 | Changed | Code description changed. |
| Pre-1990 | Added | Code added. |
Get instant expert-level medical coding assistance.