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The CPT® Code 84439 refers to the laboratory test for free thyroxine, commonly known as T4. This test involves obtaining a blood sample to measure the levels of free thyroxine in the bloodstream. Thyroxine is a crucial hormone produced by the thyroid gland, and it plays a significant role in regulating various metabolic processes in the body. The measurement of free thyroxine is essential for assessing thyroid function, as it represents the fraction of thyroxine that is not bound to proteins and is available to enter cells and exert its effects. This test is particularly important in diagnosing thyroid disorders, including hyperthyroidism, where there is an excess of thyroid hormone, and hypothyroidism, where there is a deficiency. The free thyroxine test is considered to provide a more precise evaluation of thyroid function compared to total thyroxine tests, which measure both bound and unbound thyroxine. The methodology employed for this test is electrochemiluminescent immunoassay, a sensitive and specific technique that enhances the accuracy of the results.
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The free thyroxine test (CPT® Code 84439) is indicated for the evaluation of thyroid function in various clinical scenarios. The following conditions may warrant the performance of this test:
The procedure for obtaining a free thyroxine test involves several key steps to ensure accurate results. The following outlines the procedural steps:
After the free thyroxine test is performed, there are generally no specific post-procedure care requirements for the patient. However, patients may be advised to resume their normal activities immediately following the blood draw. It is important for patients to follow up with their healthcare provider to discuss the results of the test and any necessary next steps, which may include further testing or adjustments to treatment based on the findings. If any complications arise from the blood draw, such as excessive bleeding or bruising, patients should contact their healthcare provider for guidance.
| Short Descr | ASSAY OF FREE THYROXINE | Medium Descr | ASSAY OF FREE THYROXINE | Long Descr | Thyroxine; free | 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. | GA | Waiver of liability statement issued as required by payer policy, individual case | Q4 | Service for ordering/referring physician qualifies as a service exemption | 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. | GZ | Item or service expected to be denied as not reasonable and necessary | 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 | GW | Service not related to the hospice patient's terminal condition | 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. | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study | 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. | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | 77 | Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service. | QJ | Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b) | X1 | Continuous/broad services: for reporting services by clinicians, who provide the principal care for a patient, with no planned endpoint of the relationship; services in this category represent comprehensive care, dealing with the entire scope of patient problems, either directly or in a care coordination role; reporting clinician service examples include, but are not limited to: primary care, and clinicians providing comprehensive care to patients in addition to specialty care | 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. | LT | Left side (used to identify procedures performed on the left side of the body) | Q0 | Investigational clinical service provided in a clinical research study that is in an approved clinical research study | Q5 | Service furnished under a reciprocal billing arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | Q6 | Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | RT | Right side (used to identify procedures performed on the right side of the body) | 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. | 96 | Habilitative services: when a service or procedure that may be either habilitative or rehabilitative in nature is provided for habilitative purposes, the physician or other qualified health care professional may add modifier 96 to the service or procedure code to indicate that the service or procedure provided was a habilitative service. habilitative services help an individual learn skills and functioning for daily living that the individual has not yet developed, and then keep and/or improve those learned skills. habilitative services also help an individual keep, learn, or improve skills and functioning for daily living. | AY | Item or service furnished to an esrd patient that is not for the treatment of esrd | CC | Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed) | CG | Policy criteria applied | CR | Catastrophe/disaster related | GC | This service has been performed in part by a resident under the direction of a teaching physician | GX | Notice of liability issued, voluntary under payer policy | KX | Requirements specified in the medical policy have been met | PD | Diagnostic or related non diagnostic item or service provided in a wholly owned or operated entity to a patient who is admitted as an inpatient within 3 days | PN | Non-excepted service provided at an off-campus, outpatient, provider-based department of a hospital | Q3 | Live kidney donor surgery and related services | QW | Clia waived test | SA | Nurse practitioner rendering service in collaboration with a physician | 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 | X5 | Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician | XE | Separate encounter, a service that is distinct because it occurred during a separate encounter | XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service |
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| 2013-01-01 | Changed | Medium Descriptor changed. |
| Pre-1990 | Added | Code added. |
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