Pathology/Lab Coding Alert

Answer: The reason for the test is to monitor therapeutic drug level, and that’s the overriding factor in choosing the correct code.

You need to turn to the therapeutic drug assay section, as opposed to the drug screening or definitive drug test section, to find the correct code.

Do this: Report the lab test as 80201 (Topiramate). CPT^® guidelines indicate that labs perform tests such as 80201 in the therapeutic drug assay section to monitor levels of known medications.

On the other hand, presumptive drug tests simply screen for the presence of unknown drug(s), while definitive drug tests identify and distinguish drugs and their metabolites from a specific drug class.

That’s why you should not use a drug screening code such as 80306 (Drug test(s), presumptive, any number of drug classes, any number of devices or procedures; read by instrument assisted direct optical observation (eg, utilizing immunoassay [eg, dipsticks, cups, cards, or cartridges]), includes sample validation when performed, per date of service) for this case. Nor should you use the definitive drug test code 80339 (Antiepileptics, not otherwise specified; 1-3) in this case.