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The CPT® Code 80185 refers to a laboratory test that measures the total level of phenytoin in the blood. Phenytoin, commonly known by its brand names such as Dilantin, Phenytek, or Phenytoin Prompt, is an anticonvulsant medication primarily used to manage and treat seizures. This medication functions by reducing electrical activity in the brain, which is crucial for preventing seizure episodes. The administration of phenytoin can occur either orally or through injection, depending on the patient's needs and the clinical scenario. Due to its narrow therapeutic range, it is essential to monitor both total and free phenytoin levels in patients receiving this medication. The total phenytoin level indicates the overall serum concentration of the drug, while the free phenytoin level measures the unbound portion of the drug that is biologically active. It is important to note that approximately 90 percent of phenytoin is bound to plasma proteins and is considered biologically inactive. However, this bound form can be affected by other medications that displace phenytoin from its protein binding sites, potentially leading to an increase in free phenytoin levels in the bloodstream. Regular monitoring of blood concentration levels is critical, particularly during routine follow-ups and in instances of breakthrough seizures, which may suggest that the therapeutic levels of phenytoin are insufficient. The blood sample for this test is collected through a venipuncture, which is a separately reportable procedure. Following collection, the serum is analyzed using immunoassay techniques to determine the phenytoin levels accurately.
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The phenytoin total test (CPT® Code 80185) is indicated for the following conditions:
The procedure for obtaining the phenytoin total level involves several key steps:
After the blood sample has been collected and sent for analysis, the patient may be advised to resume normal activities unless otherwise directed by their healthcare provider. It is important for the healthcare team to review the test results promptly to determine if any adjustments to the phenytoin dosage are necessary based on the total phenytoin levels measured. Patients should be monitored for any signs of adverse reactions or side effects related to phenytoin therapy, and follow-up appointments should be scheduled to reassess the patient's condition and medication efficacy.
| Short Descr | ASSAY OF PHENYTOIN TOTAL | Medium Descr | DRUG SCREEN QUANTITATIVE PHENYTOIN TOTAL | Long Descr | Phenytoin; total | 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. | GW | Service not related to the hospice patient's terminal condition | Q4 | Service for ordering/referring physician qualifies as a service exemption | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | 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. | 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. | 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. | 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. | CC | Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed) | GA | Waiver of liability statement issued as required by payer policy, individual case | GZ | Item or service expected to be denied as not reasonable and necessary | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study | 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) | XE | Separate encounter, a service that is distinct because it occurred during a separate encounter |
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| 2013-01-01 | Changed | Medium description changed per AMA 2013 corrections document dated January 25, 2013. |
| 2011-01-01 | Changed | Short description changed. |
| 1993-01-01 | Added | First appearance in code book in 1993. |
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