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The CPT® Code 84442 refers to the laboratory test for measuring thyroxine binding globulin (TBG) levels in the blood. TBG is a specific protein that plays a crucial role in the transport of thyroid hormones, specifically thyroxine (T4) and triiodothyronine (T3). It is one of three primary proteins responsible for binding these hormones, alongside transthyretin and albumin. The binding of thyroid hormones to these proteins renders them inactive, meaning they do not exert any physiological effects on the body. Therefore, the measurement of TBG is significant as it helps to differentiate between variations in thyroid hormone levels that may be due to changes in TBG concentration rather than actual thyroid function. In cases where individuals exhibit abnormal levels of total thyroid hormones, either elevated or decreased, the TBG test can assist healthcare providers in determining whether these changes are indicative of a thyroid disorder, such as hypothyroidism or hyperthyroidism, or simply a result of variations in TBG levels. The test is conducted using chemiluminescent immunoassay methodology, which is a sensitive and specific technique for quantifying TBG in the serum.
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The thyroxine binding globulin (TBG) test, coded as CPT® 84442, is indicated for the evaluation of thyroid function in patients who may present with abnormal thyroid hormone levels. The following conditions may warrant the performance of this test:
The procedure for conducting the TBG test involves several key steps to ensure accurate measurement of thyroxine binding globulin levels. The following outlines the procedural steps:
After the TBG test is performed, there are generally no specific post-procedure care requirements for the patient. The patient may resume normal activities immediately following the blood draw. However, it is advisable for the healthcare provider to discuss the results with the patient once they are available, as this will help in determining any necessary follow-up actions or treatments based on the TBG levels and overall thyroid function assessment.
| Short Descr | ASSAY OF THYROID ACTIVITY | Medium Descr | ASSAY OF THYROXINE BINDING GLOBULIN | Long Descr | Thyroxine binding globulin (TBG) | 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 | 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 | Q4 | Service for ordering/referring physician qualifies as a service exemption |
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| 2013-01-01 | Changed | Medium Descriptor changed. |
| Pre-1990 | Added | Code added. |
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