CPT® Code 80163

The CPT® Code 80163 refers to a laboratory test specifically designed to measure the levels of free digoxin in the bloodstream. Digoxin, commonly known by its brand name Lanoxin, is classified as a cardiac glycoside, a type of medication that plays a crucial role in managing various heart conditions. It works by controlling the levels of sodium and potassium within cardiac cells, which is essential for maintaining proper heart function. This medication is primarily prescribed for patients suffering from atrial fibrillation, atrial flutter, and congestive heart failure. By increasing the strength of cardiac muscle contractions, digoxin enhances cardiac output while simultaneously lowering heart rate and venous pressure, making it a vital treatment option for these conditions. Due to its narrow therapeutic window, careful monitoring of digoxin levels is necessary to avoid toxicity. The antidotal treatment for digoxin toxicity is available in the form of Digibind, which contains Digoxin Immune FAB. The test for total digoxin, identified by CPT® Code 80162, measures both the inactive digoxin that is bound to Fab fragments and the active free digoxin. In contrast, the test for free digoxin, represented by CPT® Code 80163, is particularly useful in specific clinical scenarios. It can help evaluate breakthrough digoxin toxicity in patients with renal failure, assess the need for additional anti-digoxin Fab, determine the appropriate timing for reintroducing digoxin therapy, and monitor patients who may have digoxin-like immune reactive factors. To ensure accurate results, the blood sample for measuring free digoxin must be obtained through a separately reportable venipuncture, ideally 6-8 hours after the last dose of the medication.