CPT® Code 80167

The CPT® Code 80167 refers to a laboratory test specifically designed to monitor therapeutic levels of felbamate, which is an antiepileptic medication utilized in the treatment of various types of seizures. This test is crucial for therapeutic drug monitoring, as it aids healthcare providers in optimizing the dosage of felbamate to ensure its effectiveness while minimizing the risk of toxicity. Monitoring is particularly important because the therapeutic levels of felbamate can be influenced by the presence of other medications, such as barbiturates and phenytoin, which may alter its serum concentration when co-administered. The elimination half-life of felbamate ranges from 13 to 23 hours, indicating the time it takes for the concentration of the drug in the bloodstream to reduce by half. For effective treatment, serum concentration trough levels of felbamate should ideally be maintained between 30 to 60 mcg/mL. Levels exceeding 60 mcg/mL can lead to toxicity, which poses serious health risks, including life-threatening conditions such as aplastic anemia or liver failure. To perform this test, a blood specimen is collected just before the patient's next scheduled dose of felbamate. The collected sample is then centrifuged within two hours to separate the serum from the blood cells and is placed in a plastic vial for analysis. The concentration levels of felbamate are determined using quantitative liquid chromatography-tandem mass spectrometry, a precise method that allows for accurate measurement of drug levels in the serum.