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Official Description

Oxygen uptake, expired gas analysis; rest, indirect (separate procedure)

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 94690 refers to a specific pulmonary function test that measures oxygen uptake through an expired gas analysis conducted at rest. This procedure is essential for assessing how effectively the lungs are able to take in oxygen during normal breathing. In this test, the patient inhales room air through a one-way valve and subsequently exhales into an airtight container. The gases that are exhaled are collected and analyzed using an electronic gas analyzer, which determines the concentrations of oxygen (O2) and carbon dioxide (CO2) present in the expired air. This analysis provides valuable insights into the respiratory function of the patient. Unlike other related procedures, such as CPT® Code 94680, which measures oxygen uptake during both rest and exercise, CPT® Code 94690 focuses solely on the assessment of oxygen uptake at rest. It is important to note that this procedure is performed indirectly, utilizing arterial puncture to obtain blood samples for gas analysis, rather than directly measuring the expired gases. The results of this test are crucial for physicians in diagnosing and managing various pulmonary conditions, as they provide a clear picture of the patient's respiratory efficiency at rest.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The procedure associated with CPT® Code 94690 is indicated for various clinical scenarios where assessment of oxygen uptake at rest is necessary. The following conditions may warrant the performance of this test:

  • Assessment of Respiratory Function This procedure is utilized to evaluate the efficiency of the lungs in oxygen uptake, particularly in patients with suspected pulmonary disorders.
  • Preoperative Evaluation It may be indicated for patients undergoing surgical procedures, especially those with known respiratory issues, to assess their pulmonary function prior to anesthesia.
  • Monitoring of Chronic Respiratory Conditions Patients with chronic obstructive pulmonary disease (COPD), asthma, or other chronic lung diseases may require this test to monitor their respiratory status over time.
  • Evaluation of Exercise Capacity Although this specific code pertains to rest, it may be part of a broader assessment that includes exercise testing to evaluate overall exercise capacity and oxygen utilization.

2. Procedure

The procedure for CPT® Code 94690 involves several key steps to accurately measure oxygen uptake at rest through indirect means. The following outlines the procedural steps:

  • Step 1: Patient Preparation The patient is prepared for the test by ensuring they are at rest and have not engaged in any strenuous activity prior to the procedure. This is crucial for obtaining accurate baseline measurements of oxygen uptake.
  • Step 2: Arterial Puncture An arterial puncture is performed to obtain a blood sample. This step is essential as it allows for the analysis of blood gases, which will indirectly indicate the oxygen uptake by the lungs.
  • Step 3: Blood Gas Analysis The collected blood sample is analyzed for its oxygen and carbon dioxide content. This analysis provides the necessary data to determine how much oxygen is being utilized by the body at rest.
  • Step 4: Documentation of Findings The physician compiles the results of the blood gas analysis into a written report, detailing the findings related to the patient's oxygen uptake at rest.

3. Post-Procedure

After the completion of the procedure associated with CPT® Code 94690, the patient may be monitored briefly to ensure there are no immediate complications from the arterial puncture. The physician will review the results of the blood gas analysis and discuss the findings with the patient, which may lead to further diagnostic testing or treatment options based on the results. It is important for the patient to follow any specific post-procedure instructions provided by the healthcare provider, especially if additional tests or follow-up appointments are necessary.

Short Descr O2 UPTK EXP GAS ALYS REST
Medium Descr O2 UPTAKE EXP GAS ANALYSIS REST INDIRECT SPX
Long Descr Oxygen uptake, expired gas analysis; rest, indirect (separate procedure)
Status Code Active Code
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51) 0 - No payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator STV-Packaged Codes
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T2D - Other tests - other
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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.
XE Separate encounter, a service that is distinct because it occurred during a separate encounter
25 Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service: it may be necessary to indicate that on the day a procedure or service identified by a cpt code was performed, the patient's condition required a significant, separately identifiable e/m service above and beyond the other service provided or beyond the usual preoperative and postoperative care associated with the procedure that was performed. a significant, separately identifiable e/m service is defined or substantiated by documentation that satisfies the relevant criteria for the respective e/m service to be reported (see evaluation and management services guidelines for instructions on determining level of e/m service). the e/m service may be prompted by the symptom or condition for which the procedure and/or service was provided. as such, different diagnoses are not required for reporting of the e/m services on the same date. this circumstance may be reported by adding modifier 25 to the appropriate level of e/m service. note: this modifier is not used to report an e/m service that resulted in a decision to perform surgery. see modifier 57 for significant, separately identifiable non-e/m services, see modifier 59.
52 Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
95 Synchronous telemedicine service rendered via a real-time interactive audio and video telecommunications system: synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system.
CQ Outpatient physical therapy services furnished in whole or in part by a physical therapist assistant
CR Catastrophe/disaster related
GA Waiver of liability statement issued as required by payer policy, individual case
GC This service has been performed in part by a resident under the direction of a teaching physician
GP Services delivered under an outpatient physical therapy plan of care
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
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
GZ Item or service expected to be denied as not reasonable and necessary
KX Requirements specified in the medical policy have been met
TC Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
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Pre-1990 Added Code added.
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