Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilot© Copyright 2026 American Medical Association. All rights reserved.
The CPT® Code 80165 refers to a laboratory test specifically designed to measure the concentration of free valproic acid, also known as dipropylacetic acid or depakote. Valproic acid is classified as an anticonvulsant medication, commonly utilized in the management of seizure disorders, the manic phase of bipolar disorder, and migraine headaches. The mechanism of action for valproic acid involves altering the levels of certain neurotransmitters in the brain, which helps to stabilize mood and prevent seizures. The test for total valproic acid, identified by CPT® Code 80164, serves multiple purposes, including monitoring the effectiveness of drug therapy, assessing patient adherence to the prescribed treatment regimen, and evaluating the potential for drug toxicity. In contrast, the test for free valproic acid, represented by CPT® Code 80165, is particularly useful in clinical scenarios where the total valproic acid concentration falls within the normal range, yet there are concerns regarding toxicity. This situation may arise in patients who exhibit altered or unpredictable protein binding capacity, which can lead to elevated levels of free valproic acid. To perform this test, a blood sample is collected through a separately reportable venipuncture, ideally just before the administration of medication, to capture the trough level of the drug. The laboratory analysis involves testing serum or plasma for total valproic acid using fluorescence polarization immunoassay techniques, while free valproic acid is quantified through enzyme multiplied immunoassay methods.
© Copyright 2026 Coding Ahead. All rights reserved.
The test for free valproic acid (CPT® Code 80165) is indicated for the following conditions:
The procedure for obtaining a free valproic acid level involves several critical steps:
After the procedure, the patient may resume normal activities unless otherwise instructed by the healthcare provider. It is important to monitor the patient for any adverse reactions related to the venipuncture, such as bruising or discomfort at the site. The results of the free valproic acid test will be interpreted in conjunction with clinical findings and total valproic acid levels to guide further treatment decisions. Follow-up appointments may be necessary to discuss the results and any adjustments to the medication regimen based on the findings.
| Short Descr | DIPROPYLACETIC ACID FREE | Medium Descr | DRUG SCREEN QUANT DIPROPYLACETIC ACID FREE | Long Descr | Valproic acid (dipropylacetic acid); 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) | T2D - Other tests - other | 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. | 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. | 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. | 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. | 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. | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | GW | Service not related to the hospice patient's terminal condition | 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 |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2015-01-01 | Added | Added |
Get instant expert-level medical coding assistance.