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The CPT® Code 80168 refers to a laboratory test specifically designed to measure the levels of ethosuximide in the blood. Ethosuximide, commonly known by its brand name Zarontin, is classified as an anticonvulsant medication primarily used in the management of seizures, particularly absence seizures. This blood test is crucial for monitoring the concentration of ethosuximide in patients who are undergoing treatment, as maintaining appropriate therapeutic levels is essential for the drug's efficacy and safety. The test is typically performed at the initiation of treatment, at regular intervals thereafter, and also during instances of breakthrough seizure activity, which may suggest that the blood levels of the medication have fallen below the therapeutic range. To conduct this test, a blood sample is collected through a procedure known as venipuncture, which is separately reportable. Following the collection, the serum is analyzed using an enzyme immunoassay method, a sensitive technique that allows for accurate measurement of the drug concentration in the blood.
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The blood test for ethosuximide levels is indicated for several specific clinical scenarios, including:
The procedure for measuring ethosuximide levels involves several key steps, which are outlined as follows:
After the blood sample has been collected and tested, the patient may resume normal activities unless otherwise directed by their healthcare provider. It is important for the healthcare team to communicate the results of the ethosuximide level test to the patient, as this information will guide any necessary adjustments to their treatment regimen. If the test indicates that the drug levels are outside the therapeutic range, the physician may consider modifying the dosage or frequency of administration to ensure optimal seizure control. Additionally, patients should be monitored for any side effects or adverse reactions related to ethosuximide therapy, and follow-up testing may be scheduled as needed to continue monitoring drug levels.
| Short Descr | ASSAY OF ETHOSUXIMIDE | Medium Descr | DRUG SCREEN QUANTITATIVE ETHOSUXIMIDE | Long Descr | Ethosuximide | 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 | 2 | CCS Clinical Classification | 235 - Other Laboratory |
| 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. |
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| 2013-01-01 | Changed | Medium description changed per AMA 2013 corrections document dated January 25, 2013. |
| 1993-01-01 | Added | First appearance in code book in 1993. |
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