Pathology/Lab Coding Alert

Know your specimen source, too.

New CPT® sections and new drug lists that you read about in “Part 1” on page 18 aren’t all you need to know to fathom the extent of the 2015 drug coding overhaul. If you don’t know which method your lab uses for a test and understand how CPT® restricts the codes based on that information, you don’t have a prayer of picking the right code.

Read on to continue our CPT® 2015 drug test coding primer with three more tips you need to know.

Tip 1: See How Lab Methods Constrain Code Choice

Although you’ll distinguish the new presumptive codes based on List A and List B drugs, you’ll also need to consider the lab method. “CPT® divided the drugs for presumptive tests into these two lists partly based on the common methods labs use for the analytes, with List B codes typically using methods that require more resources,” explains William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Presumptive list B tests are generally more complex, and may include preanalytical sample preparation for specific drug classes, according to Mark S. Synovec, MD, AMA CPT® editorial panel member, at the CPT® and RBRVS 2015 Annual Symposium.

Resource: The methods that labs might use for drug testing can be an alphabet soup of acronyms, like EIA for enzyme immunoassay, MS-TOF for mass spectrometry time of flight, and more. That’s why CPT® 2015 created a three-page table in the introduction to the Drug Assay section called “Definitions and Acronym Conversion Listing.” Refer to this chart to understand the acronyms used in specific CPT® 2015 codes.

Handy tool: Look at Table 1 on page 21 to learn how the lab method, drug class, and reason for the test interact to impact your code choice.

You can see from Table 1 that CPT® 2015 classifies all drug screen immunoassays and enzyme assays as presumptive tests. Labs may use many other methods for either definitive or therapeutic drug tests. So even if you know the lab method and the drug class, you might not have enough information to select the proper code. As discussed in Part 1, the reason for the test — either to monitor a prescribed drug or to test for drug abuse — can drive your code selection.

Tip 2: Focus on Specimen Source, Unit of Service

CPT® 2015 instructions state that clinicians may order the presumptive and definitive drug tests from any specimen source, unless the code specifies the specimen. For instance, a clinician may provide urine or hair to the lab for a drug screen or definitive drug assay. The test results may be qualitative or quantitative or a combination.

Therapeutic is different: On the other hand, CPT® 2015 states that for therapeutic drug assays, “the material for examination is whole blood, serum, plasma, or cerebrospinal fluid.” The instructions also state that these tests are quantitative.

“Some newer therapeutic drug assays use saliva as a specimen source, and if your lab performs one of these tests, you should probably use the appropriate therapeutic drug code despite the specimen source, because the codes don’t preclude all other specimen types,” Dettwyler says.

Unit of service: Table 1 shows the unit of service for each type of testing. You can see that three of the presumptive test codes include all list A drug classes screened on a single date of service. The other two presumptive test codes include all list B drugs evaluated in a single procedure.

On the other hand, you’ll report one code for one drug or drug class when the lab performs definitive or therapeutic drug testing. However, if the lab tests for the same drug using different specimens, you should report each test separately with modifier 59 (Distinct procedural service) or other appropriate modifier.

Tip 3: Follow Medicare Rules

If you’re billing for Medicare or other payers that follow Medicare rules this year, you can ignore a good deal of what you’ve just read. That’s because Medicare decided not to recognize any of the new CPT® screening or definitive drug test codes this year, until the agency can further study the cost-impact of the new codes.

Instead, Medicare’s intention is for labs continue to bill screening drug tests as they did in 2014, using G0434 (Drug screen, other than chromatographic; any number of drug classes, by CLIA waived test or moderate complexity test, per patient encounter) and G0431 (Drug screen, qualitative; multiple drug classes by high complexity test method [e.g., immunoassay, enzyme assay], per patient encounter).

Problem: Medicare also wanted labs to continue to bill all other drug tests as they did in 2014, but CPT® 2015 deleted or changed many drug test codes. That means labs can’t continue to use all the same CPT® codes that they did in 2014.

Solution: CMS introduced 26 new HCPCS Level II “G” codes to replace the deleted codes. Look to future issues of Pathology/Lab Coding Alert for more instruction on these changes.