Pathology/Lab Coding Alert

Distinguish presumptive, definitive, therapeutic testing.

You’ll have six new codes to use when your lab tests patient specimens for specific prescribed medications beginning Jan. 1. Read on to get the lowdown on the clinical context and test methods these codes entail.

That’s not all: Take this opportunity to refresh your understanding of the different levels of CPT^® drug testing code families you need to know.

Learn the Codes

CPT^® 2020 adds the following codes to the Therapeutic Drug Assay section:

• 80145 (Adalimumab)
• 80187 (Posaconazole)
• 80230 (Infliximab)
• 80235 (Lacosamide)
• 80280 (Vedolizumab)
• 80285 (Voriconazole)

Codes 80145, 80230, and 80280 for adalimumab, infliximab, and vedolizumab, respectively, all describe “drugs that are used for Crohn’s or ulcerative colitis,” according to Cheryl James, representing Mayo Clinic in her presentation at the CMS Annual Clinical Laboratory Public Meeting held June 24, 2019. “These are all codes that use the same technology – LC-MS/MS [liquid chromatography-tandem mass spectrometry],” she says.

Although the remaining three codes may involve similar lab methods, these tests are for drugs with different clinical indications. Clinicians may order 80187 for immunocompromised patients taking posaconazole to guard against certain fungal infections, and 80285 for patients with a specific genetic mutation who are prescribed the antifungal agent, voriconazole. For patients with partial-onset seizures taking lacosamide, clinicians may order 80235.

Payment expectations: CMS posted preliminary payment determinations for these codes in September, as described at the Annual Clinical Laboratory Public Meeting by CMS’s meeting facilitator Rasheeda Arthur, PhD. The recommended pricing is a crosswalk to 80155 (Caffeine) for codes 80145, 80230, and 80280, which currently pays $38.57. For codes 80235, 80187, and 80285, CMS recommends a crosswalk to 80199 (Tiagabine), which pays $27.11. All pricing is based on 2019 Clinical Laboratory Fee Schedule national limit amount. Crosswalks are based on codes that appear to use similar methods and resource utilization, according to CMS,

Focus Therapeutic Drug Assays

Before you use a code from the Therapeutic Drug Assay section, you need to know that the reason for the test is just as important as the name of the drug or drug class if you want to report the test correctly.

“You should use a therapeutic drug assay code only when the clinician orders a test to monitor patient response to a known, prescribed medication,” says William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Clinicians may order these tests to evaluate specific clinical scenarios such as the following:

• Change in blood concentration following dosage change
• Change in patient’s clinical state
• Patient compliance with medication regimen
• Possible toxic concentration
• Lack of treatment response due to subtherapeutic concentration
• Potential drug interaction with co-medications

Find your code: CPT^® organizes codes for therapeutic drug tests alphabetically by drug or drug class, and that will include the new codes, although several of them will be out of numerical sequence, indicated by the # symbol in CPT^®. Each code includes testing for any metabolites of the listed drug, if performed.

Unlisted: If a clinician requests levels of a therapeutic drug that isn’t listed in the therapeutic drug section, report 80299 (Quantitation of therapeutic drug, not elsewhere specified). “You may already be using 80299 for the drugs described by each of these new codes, so be sure to change to the new, specific code in 2020,” Dettwyler cautions.

Avoid: Don’t use a therapeutic drug assay code for a non-prescribed medication. If a clinician orders a test based on the suspicion that a patient is abusing a drug without a prescription, you need to turn to a definitive drug test code, even if the drug is listed in the Therapeutic Drug Assay section. You’ll read more about definitive drug test codes in the next section.

Example: If the clinician orders a quantitative test to evaluate total carbamazepine levels in a patient taking the medication for bipolar 1, you should code the test as 80156 (Carbamazepine; total). On the other hand, if a test for multiple drug classes yields a positive result for carbamazepine in a patient without a prescription for the medication, and the clinician orders a quantitative follow-up test for the drug, you should report 80339 (Antiepileptics, not otherwise specified; 1-3). CPT^® lists carbamazepine under “antiepileptics, not otherwise specified” in the definitive drug class table.

Glossary tip: A “drug class” is a collection of drugs that have similar chemical structure, or have the same mode of action, and/or serve the same clinical purpose.

Recognize CPT^® Drug Test Groupings

All drug tests aren’t therapeutic drug assays, so you need to understand how CPT^® organizes drug testing codes when clinicians order tests for reasons other than monitoring medications.

Remember that physicians order drug tests for a host of reasons, such as substance abuse screening, monitoring treatment regimens for pain management or addiction, or evaluating prescribed therapeutic drug levels.

Presumptive: Often ordered as drug “screening,” labs perform presumptive drug testing to determine the presence or absence of drugs or drug class(es). “Presumptive test results are typically qualitative, expressed as a positive or negative finding. Clinicians often order further testing for confirmation of any positive findings,” Dettwyler says.

CPT^® provides the following three codes to describe presumptive testing, based on the lab method used:

• 80305 (Drug test(s), presumptive, any number of drug classes, any number of devices or procedures; capable of being read by direct optical observation only (eg, utilizing immunoassay [eg, dipsticks, cups, cards, or cartridges]), includes sample validation when performed, per date of service)
• 80306 (... 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)
• 80307 (… by instrument chemistry analyzers (eg, utilizing immunoassay [eg, EIA, ELISA, EMIT, FPIA, IA, KIMS, RIA]), chromatography (eg, GC, HPLC), and mass spectrometry either with or without chroma­tography, (eg, DART, DESI, GC-MS, GC-MS/MS, LC-MS, LC-MS/MS, LDTD, MALDI, TOF) includes sample validation when performed, per date of service).

According to CPT^® Assistant, March 2017, Volume 27: Issue 3, “Some examples of drugs or a drug class that are commonly assayed by presumptive tests, followed by definitive testing are: alcohols, amphetamines, barbiturates/sedatives, benzodiazepines, cocaine and metabolites, methadone, antihistamines, stimulants, opioid analgesics, salicylates, cardiovascular drugs, antipsychotics, and cyclic antidepressants.”

More: You should also be aware of code H0003 (Alcohol and/or drug screening; laboratory analysis of specimens for presence of alcohol and/or drugs), which many state Medicaid agencies must use to identify mental health services related to alcohol and drug treatment services.

Definitive: To identify and possibly quantify specific drugs and their metabolites, clinicians may order a definitive drug test, either following a positive presumptive test, or as the initial test. Although CPT® provides codes 80320-80377 for specific drug classes, such as alcohols (80320), Medicare won’t pay for those codes and requires you to use one of the following instead:

• G0480 (Drug test(s), definitive, utilizing (1) drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including, but not limited to GC/MS (any type, single or tandem) and LC/MS (any type, single or tandem and excluding immuno­assays (e.g., IA, EIA, ELISA, EMIT, FPIA) and enzymatic methods (e.g., alcohol dehydrogenase)), (2) stable isotope or other universally recognized internal standards in all samples (e.g., to control for matrix effects, interferences and variations in signal strength), and (3) method or drug-specific calibration and matrix-matched quality control material (e.g., to control for instrument variations and mass spectral drift); qualitative or quantitative, all sources, includes specimen validity testing, per day; 1-7 drug class(es), including metabolite(s) if performed)
• G0481 (... 8-14 drug class(es), including metabolite(s) if performed)
• G0482 (... 15-21 drug class(es), including metabolite(s) if performed)
• G0483 (... 22 or more drug class(es), including metabolite(s) if performed)
• G0659 (Drug test(s), definitive, utilizing drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including but not limited to GC/MS (any type, single or tandem) and LC/MS (any type, single or tandem), excluding immunoassays (e.g., IA, EIA, ELISA, EMIT, FPIA) and enzymatic methods (e.g., alcohol dehydro­genase), performed without method or drug-specific calibration, without matrix-matched quality control material, or without use of stable isotope or other universally recognized internal standard(s) for each drug, drug metabolite or drug class per specimen; qualitative or quantitative, all sources, includes specimen validity testing, per day, any number of drug classes).