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The CPT® Code 86366 refers to the testing for muscle-specific kinase (MuSK) antibodies, which are critical in the diagnosis of myasthenia gravis (MG), a rare neuromuscular disorder characterized by weakness and fatigue of voluntary muscles. MuSK antibodies are proteins that play a significant role at the neuromuscular junction, where nerve endings connect with muscle fibers. In individuals with MG, these antibodies can disrupt the transmission of signals from nerves to muscles, leading to various symptoms. The condition can manifest in two forms: ocular myasthenia gravis, which primarily affects the eye muscles, and generalized myasthenia gravis, which can impact muscles throughout the body. Symptoms associated with ocular MG include drooping eyelids, double vision, and weakness in eye muscle control. In contrast, generalized MG may present with additional challenges such as weakness in neck muscles, difficulties with chewing, swallowing, or speaking, slurred speech, and issues with walking or breathing. It is noteworthy that approximately 15% of individuals with MG experience only ocular symptoms. The MuSK antibody test is particularly valuable in diagnosing MG in patients who exhibit symptoms but do not test positive for acetylcholine receptor (AChR) antibodies, which are present in the majority of MG cases. Only about 10%-15% of individuals with MG lack AChR antibodies, and those who are negative for AChR but positive for MuSK antibodies are often diagnosed with generalized MG and may have different treatment responses compared to those with AChR antibodies.
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The MuSK antibody test is indicated for the following conditions:
The procedure for testing MuSK antibodies involves the following steps:
After the MuSK antibody test is performed, there are generally no specific post-procedure care requirements for the patient. However, it is important for the healthcare provider to discuss the results with the patient once they are available. If MuSK antibodies are detected, the physician may consider further evaluation and treatment options tailored to the patient's specific condition, particularly if they are diagnosed with generalized myasthenia gravis. Patients should be monitored for any symptoms related to MG and receive appropriate follow-up care as needed.
| Short Descr | MUSCLE-SPECIFIC KINASE ANTB | Medium Descr | MUSCLE-SPECIFIC KINASE ANTIBODY | Long Descr | Muscle-specific kinase (MuSK) antibody | 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) | none | MUE | 1 |
| 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. | Q4 | Service for ordering/referring physician qualifies as a service exemption |
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| 2024-01-01 | Added | Code Added. |
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