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Pathology/Lab Coding Alert

Don't Double Dip for 'Multiplex' Tests

Add 87483 to your infectious agent detection arsenal.

If you think you know all the opportunities and snares for reporting infectious agent antigen detection codes, think again. You might find some pitfalls ahead if you haven’t considered the “multiplex” tests that evaluate a specimen for multiple organisms.

Take a closer look with our expert advice on multiplex infectious-agent codes and how to use them.

Recognize Multiplex Tests

CPT® provides a large family of codes (87470-87798) that describe tests to evaluate primary-source specimens (such as blood) for the presence of infectious agent antigens using nucleic acid techniques.

Specifically, these tests seek to find bits of RNA or DNA “targets” in the specimen that are unique to certain infectious organisms. If these targets are present, it indicates infection with the associated organism. These tests typically use methods such as reverse transcription and polymerase chain reaction (PCR) to isolate and “amplify” the signal from the target nucleic acids.

A multiplex test is a single test procedure that evaluates a single specimen for multiple targets. Within the larger 87470-87798 family, most codes describe identification of a single organism, but a few describe tests for a group of organisms, as follows:

  • 87483, Infectious agent detection by nucleic acid (DNA or RNA); central nervous system pathogen (e.g., Neisseria meningitidis, Streptococcus pneumoniae, Listeria, Haemophilus influenzae, E. coli, Strepto­coccus agalactiae, enterovirus, human parechovirus, herpes simplex virus type 1 and 2, human herpesvirus 6, cytomegalovirus, varicella zoster virus, Crypto­coccus), includes multiplex reverse transcription, when performed, and multiplex amplified probe technique, multiple types or subtypes, 12-25 targets.
  • 87505-87507, … gastrointestinal pathogen (e.g., Clostridium difficile, E. coli, Salmonella, Shigella, norovirus, Giardia), includes multiplex reverse transcription, when performed, and multiplex amplified probe technique, multiple types or subtypes …Each code in this sequence indicates an increasing number of targets.
  • 87631-87633, … respiratory virus (e.g., adenovirus, influenza virus, coronavirus, metapneumovirus, parainfluenza virus, respiratory syncytial virus, rhinovirus…), includes multiplex reverse transcription, when performed, and multiplex amplified probe technique, multiple types or subtypes … This series also represents an increasing number of targets for each subsequent code.

You may not be familiar with 87483, because CPT® added this code for 2017. The test describes simultaneous detection and identification of nucleic acids from multiple bacteria, viruses, and fungi directly from the central nervous system, according to Robert Jerris, PhD, D (ABMM), representing the American Society for Microbiology, speaking at the annual Clinical Laboratory Fee Schedule public meeting to discuss the new codes.

Follow CPT® Guidelines

You’ll find general instructions for using any infectious agent antigen detection code at the beginning of the CPT® section beginning with code 87260.

Although the guidelines don’t single out the multiplex codes, you’ll get in trouble if you follow some of these instructions literally when billing the multiplex tests.

CPT® states, “When separate results are reported for different species or strain of organisms, each result should be coded separately. Use modifier 59 when separate results are reported for different species or strains that are described by the same code.” That instruction essentially makes the unit of service for the infectious agent antigen detection codes the species or strain identified by a single test.

Distinction: Although the unit of service for multiplex codes is still the single test procedure, it is not based on the target organism species or strain. Instead, the multiplex codes include multiple target organisms or species or strains.

Not inclusive: In fact, the multiplex codes include all organisms evaluated in the single test procedure from a single specimen, even if those organisms aren’t listed in the code definition. Each multiplex code definition includes a parenthetic list of organisms that begins with “e.g.” An “e.g.” list means that the items listed are “for example.” Specifically for CPT® codes, “e.g.” means the list is not inclusive. Even if your lab evaluates for all the organisms listed in the example plus even more organisms, you should use just one unit of the code.

Watch for CCI Direction, Too

In response to the new 87483 code, CMS updated the NCCI Policy Manual for 2017 with some instructions about billing Medicare for the multiplex infectious agent antigen detection codes.

The instructions affirm the CPT® rules that these codes aren’t inclusive. “The code descriptors identify some microorganisms, but not all, that might be tested by these methodologies for the respective anatomic regions,” according to the manual.

Avoid double billing: The Policy Manual goes on to state that you “should not report separate CPT® codes for nucleic acid testing by these methodologies for other microorganisms that might cause disease in the respective anatomic region.”

Bill per site: The CMS instructions state that the codes, “describe an anatomic region and the number of ‘targets’ tested.” The guidelines go on to clarify that “only one multiplex testing code summing the testing for all ‘targets’ should be reported [for] microorganisms that might cause disease in the anatomic region described by the code.”

One exception: NCCI allows one concession to billing for more than one test in these cases. “If it is medically reasonable and necessary to test by a different methodology for other microorganisms not included in the multiplex test that might cause disease in the respective anatomic region, the test may be reported separately,” according to CMS (emphasis added).