Esoteric Testing Market Segments

Esoteric Testing Market Segments

The esoteric testing market segments can be seen in their simplest form in two areas:

  1. chemiluminescence immunoassay
  2. enzyme-linked immunosorbent assay radioimmunoassay, mass spectrometry, flow cytometry, real-time PCR (qPCR), and other technical modalities of testing.[i]

Because these tests are performed differently than in a routine medical laboratory, esoteric testing is most likely to be performed instead by a reference laboratory.  “Sending out” for such tests where specialized knowledge and techniques are required is expected in the healthcare industry.  According to our data analytics, these tests are sent to reference laboratories 100 percent of the time and should be billed with CPT code modifier 90.

Chemiluminescence Immunoassay Esoteric Tests

A quantitative immunoassay is performed to detect a chemical substance (analyte) other than an antigen or antibody which is produced by the body in response to an infectious agent. There are many immunoassays for non-infectious antigens and antibodies that are reported with these codes.  There are also non-infectious diseases that may be tested using this approach.  These include:

  • myasthenia gravis[ii] (with or without acute exacerbation) using ICD-10 CM code G70.00 or G70.01.
  • Also, pancreatic disease (precision is essential to test for and accurately use the results of an esoteric test because there are over 300 potential ICD-10 diagnosis codes associated with some form of pancreatic disease, including alcohol-induced chronic pancreatitis ICD-10 K86.8 and K86.1, which is a non-specific code ‘other chronic pancreatitis’);
  • parathyroid disease (again there are over 300 potential codes, so specificity is essential).

Examples of specific substances reported with these codes include neuronal antibodies, cytokine production, and vascular endothelial growth factor.   Chemiluminescence Immunoassay Esoteric Tests – Radioimmunoassay (RIA)

Quantitative testing measures the exact amount or level of the substance in the test sample. Generally, it is recommended that providers use CPT code 83519 for the quantitative radioimmunoassay (RIA) testing method. RIA uses radioisotope labeled antigens or other radioisotope labeled substances along with unlabeled substances to bind the specific antigen or substance being tested. The binding of the importance to the radiolabeled antigen or other substance allows the substance to be measured (quantified). RIA enables the measurement of minute quantities of enzymes, hormones, or other substances.

Chemiluminescence Immunoassay Esoteric Tests – Non-Radioimmunoassay (RIA)

For other technologies such as mass spectrometry, flow cytometry, real-time PCR (qPCR), it is recommended that providers bill CPT 83520 for quantitative testing methods other than radioimmunoassay. Codes are reported for each substance class, or subclass tested using this technique.  For example, when testing for interleukin 4, 5, 10, and 13 by multi-analyte fluorescence detection, CPT 83520 would be reported four times.   The CSS clinical classification is 233 – Laboratory – Chemistry and Hematology for this code

Enzyme-linked immunosorbent assay esoteric tests

According to the American Medical Association, June 2020 CPT Editorial Panel news, the CPT code 87426 was approved:

87426 severe acute respiratory syndrome coronavirus (e.g., SARS-CoV, SARS-CoV-2 [COVID-19]) The new codes will allow for more accurate reporting of immunoassay testing for SARS-Coronavirus antigen. It is worth noting that the code is not specific for SARS-CoV-2, and it could be used for an immunoassay that detects antigenic proteins for either SARS-CoV or SARS-CoV-2. As the antigenic proteins across the SARS-Coronavirus family are highly conserved, the assays currently available are not capable of distinguishing between SARS-CoV and SARS-CoV-2.



CPT code 87301 Infectious agent antigen detection by immunoassay technique, (e.g., enzyme immunoassay [EIA], enzyme-linked immunosorbent assay [ELISA], immunochemiluminometric assay [IMCA]) qualitative or semiquantitative, multiple-step method; adenovirus enteric types 40/41.  The CSS clinical classification is 206 – Microscopic examination (bacterial smear, culture, toxicology).

[i] PCRELISA combines an immunological method (ELISA) to detect and quantify specific PCR products directly after immobilization of DNA on a microtiter plate. PCRELISA is also less commonly known as PCR-ELOSA (polymerase chain reaction-enzyme-linked oligosorbent assay).  See Sue MJ, Yeap SK, Omar AR, Tan SW. Application of PCR-ELISA in molecular diagnosis. Biomed Res Int. 2014;2014:653014. doi: 10.1155/2014/653014. Epub 2014 May 27. PMID: 24971343; PMCID: PMC4058250.

[ii] Myasthenia gravis is an autoimmune disease that primarily causes weakness in the voluntary muscles (e.g., eye movement, facial expressions, swallowing). Weakness worsens with activity and improves with rest. It is caused when the body’s immune system makes antibodies that block or change some of the nerve signals to these muscles. Symptoms may go into periods of remission which may be temporary or permanent.

Medicare Local Coverage Determinations (Medicare LCDs) are not published that are specific to these codes at this time however Medicare’s standard guidance regarding whether tests are medically necessary and that the patient / beneficiary clinical documentation is adequate to support the need for testing applies.  Commercial payer medical policies are evolving as well as the time that this was published.  Like the other codes above, berenson-eggers tos (betos) lists the code clinical category as ‘other non-Medicare.’ The BETOS coding system was developed for analyzing Medicare expenditures. The coding system covers HCPCS codes; assigns a HCPCS code to only one BETOS code; consists of clinical categories


Michael F. Arrigo

Michael Arrigo, an expert witness, and healthcare executive, brings four decades of experience in the software, financial services, and healthcare industries. In 2000, Mr. Arrigo founded No World Borders, a healthcare data, regulations, and economics firm with clients in the pharmaceutical, medical device, hospital, surgical center, physician group, diagnostic imaging, genetic testing, health I.T., and health insurance markets. His expertise spans the federal health programs Medicare and Medicaid and private insurance. He advises Medicare Advantage Organizations that provide health insurance under Part C of the Medicare Act. Mr. Arrigo serves as an expert witness regarding medical coding and billing, fraud damages, and electronic health record software for the U.S. Department of Justice. He has valued well over $1 billion in medical billings in personal injury liens, malpractice, and insurance fraud cases. The U.S. Court of Appeals considered Mr. Arrigo's opinion regarding loss amounts, vacating, and remanding sentencing in a fraud case. Mr. Arrigo provides expertise in the Medicare Secondary Payer Act, Medicare LCDs, anti-trust litigation, medical intellectual property and trade secrets, HIPAA privacy, health care electronic claim data Standards, physician compensation, Anti-Kickback Statute, Stark law, the Affordable Care Act, False Claims Act, and the ARRA HITECH Act. Arrigo advises investors on merger and acquisition (M&A) diligence in the healthcare industry on transactions cumulatively valued at over $1 billion. Mr. Arrigo spent over ten years in Silicon Valley software firms in roles from Product Manager to CEO. He was product manager for a leading-edge database technology joint venture that became commercialized as Microsoft SQL Server, Vice President of Marketing for a software company when it grew from under $2 million in revenue to a $50 million acquisition by a company now merged into Cincom Systems, hired by private equity investors to serve as Vice President of Marketing for a secure email software company until its acquisition and multi $million investor exit by a company now merged into Axway Software S.A. (Euronext: AXW.PA), and CEO of one of the first cloud-based billing software companies, licensing its technology to Citrix Systems (NASDAQ: CTXS). Later, before entering the healthcare industry, he joined Fortune 500 company Fidelity National Financial (NYSE: FNF) as a Vice President, overseeing eCommerce solutions for the mortgage banking industry. While serving as a Vice President at Fortune 500 company First American Financial (NYSE: FAF), he oversaw eCommerce and regulatory compliance technology initiatives for the top ten mortgage banks and led the Sarbanes Oxley Act Section 302 internal controls I.T. audit for the company, supporting Section 404 of the Sarbanes Oxley Act. Mr. Arrigo earned his Bachelor of Science in Business Administration from the University of Southern California. Before that, he studied computer science, statistics, and economics at the University of California, Irvine. His post-graduate studies include biomedical ethics at Harvard Medical School, biomedical informatics at Stanford Medical School, blockchain and crypto-economics at the Massachusetts Institute of Technology, and training as a Certified Professional Medical Auditor (CPMA). Mr. Arrigo is qualified to serve as a director due to his experience in healthcare data, regulations, and economics, his leadership roles in software and financial services public companies, and his healthcare M&A diligence and public company regulatory experience. Mr. Arrigo is quoted in The Wall Street Journal, Fortune Magazine, Kaiser Health News, Consumer Affairs, National Public Radio (NPR), NBC News Houston, USA Today / Milwaukee Journal Sentinel, Medical Economics, Capitol ForumThe Daily Beast, the Lund Report, Inside Higher Ed, New England Psychologist, and other press and media outlets. He authored a peer-reviewed article regarding clinical documentation quality to support accurate medical coding, billing, and good patient care, published by Healthcare Financial Management Association (HFMA) and published in Healthcare I.T. News. Mr. Arrigo serves as a member of the board of directors of a publicly traded company in the healthcare and data analytics industry, where his duties include: member, audit committee; chair, compensation committee; member, special committee.

Leave a Reply