COVID-19 testing

As health care organizations continue to respond to COVID-19, Mayo Clinic Laboratories remains in full service for your reference laboratory needs. We offer a comprehensive menu of COVID-19 and related testing.

Learn more about our testing

Molecular (PCR) testing

Molecular testing is used to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. This real-time polymerase chain reaction (PCR) test can identify SARS-CoV-2 from a variety of clinical samples from patients with suspected COVID-19, including nasopharyngeal swabs and throat swabs.

Since the beginning of the pandemic, Mayo Clinic Laboratories has proactively brought up multiple COVID-19 molecular testing platforms to meet the needs of clients around the world. In addition, we introduced a universal test code to enable us to dynamically route testing to available platforms and optimize turnaround time.

The following tests are recommended only for patients who meet current clinical and/or epidemiologic criteria defined by federal, state, or local public health directives.

COFLU | Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) RNA and Influenza Virus Type A and Type B RNA Detection, PCR, Varies

Detection and differentiation of coronavirus disease 2019 (COVID-19) illness (due to SARS-CoV-2) and influenza A and B viral infection in a single test using upper respiratory tract specimens.

Serology testing

Serologic, or antibody testing, is used to identify individuals who were previously infected with SARS-CoV-2. These individuals may have been symptomatic or asymptomatic. Serologic testing should not be used to diagnose active COVID-19 because the development of an immune or antibody response is delayed, and can take 5 to 14 days after symptom onset to become detectable.  

Serologic testing also plays an important role in the qualification of convalescent plasma for COVID-19 therapy. Our test CPCOV can help identify newly recovered patients with high antibody levels who can donate their antibody-rich blood, known as convalescent plasma, to potentially save other patients with severe COVID-19.

This type of testing can also help drive research, especially for vaccine clinical trials, to determine efficacy and long-term immunity.

 

VCOV2 | Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) IgG Antibody, Serum

Useful for detection of IgG-class antibodies against SARS-CoV-2, the virus that causes COVID-19.

CPCOV | Coronavirus Disease 2019 (COVID-19) Convalescent Plasma Manufacture, IgG, Serum

Useful for the manufacturing of SARS-CoV-2 convalescent plasma units.

Related testing

Note: As discussed in a recent Mayo Clinic Proceedings article, there is still no high-quality evidence to support many proposed drug therapies. We encourage the enrollment of eligible patients to multiple ongoing clinical trials that assess the efficacy and safety of these candidate therapies. Until the results of controlled trials are available, none of the suggested therapeutics is clinically proven as an effective therapy for COVID-19.

However, as research and clinical experience continue to evolve around management of COVID-19 patients, clinicians may find use in the following laboratory tests:

IL6 | Interleukin 6, Plasma

Severe COVID-19 patients are characterized by a higher baseline IL-6 level compared to non-severe infections. In critically ill patients with COVID-19, IL-6 levels were almost tenfold higher. While it is not clear whether elevation in IL-6 has a causal association with pro-inflammatory damage of the lungs or is just a consequence of the lung infection, attempts at blocking IL-6 by using monoclonal antibodies directed against IL-6 receptors have garnered interest as a potential therapeutic option.

TBBS | Quantitative Lymphocyte Subsets: T, B, and Natural Killer (NK), Blood

One of the most characteristic changes in COVID-19 patients is lymphopenia. In addition to total lymphocytes, T cells (CD4+ T cells, CD8+ T cells), B cells, and NK cells are all decreased in COVID-19 patients compared to healthy controls. These cell counts correlate with severity and also normalize in post-treatment patients who recover. For severe cases of COVID-19, further analysis may be required and experts in Mayo Clinic’s Cellular and Molecular Immunology Laboratory are available for further discussion.

TCZ | Tocilizumab Quantitation, Serum

Tocilizumab (TOC) is a recombinant humanized IgG1 kappa monoclonal antibody that targets the IL-6 receptor to block the pro-inflammatory effects of IL-6 mediated signaling. IL-6 is also a critical component of cytokine release syndrome (CRS), which results from an overactive immune response and can occur in COVID-19 patients. This immunoassay is designed to determine TOC concentrations in human serum.

As noted in the recent Mayo Clinic Proceedings article linked above, during the current COVID-19 outbreak, a cohort of 21 febrile patients received TOC, and this led to defervescence, reduction in supplemental oxygenation, and improvement in clinical symptoms. However, the absence of a control group cautions against the optimistic interpretation of this promising data. Clinical trials are underway to evaluate the efficacy and safety of TOC for IL-6 inhibition in the management of COVID-19.

Additional references for TOC:

  • Tanaka T, Narazaki M, Kishimoto T. IL-6 in inflammation, immunity, and disease. Cold Spring Harb Perspect Biol. 2014;6(10):a016295.
  • Sheppard M, Laskou F, Stapleton PP, Hadavi S, Dasgupta B. Tocilizumab (Actemra). Hum Vaccin Immunother. 2017;13(9):1972-1988.

CYPAN | Cytokine Panel, Plasma

Cytokines are important mediators of cell-to-cell communication within the innate and adaptive immune systems. The expression of most cytokines is highly regulated, and generally occurs in response to foreign or self-antigenic stimulation. As a group, cytokines and their receptors represent a highly complex and critical regulator of a normal immune response. This immunoassay is designed to help understand the etiology of infectious (viral) or chronic inflammatory diseases, when used in conjunction with clinical information and other laboratory testing.

Additional references for CYPAN:

  • Teijara, JR. Type I interferons in viral control and immune regulation. Curr Opin Virol. 2016;16:31-40.
  • Tisoncki, JR, Korth, MJ, Simmons, CP, et al. Into the eye of the cytokine storm. Microbiol Mol Biol Rev. 2012;76:16-32.
  • Garcia Borrega, J, Godel, P, Ruger, MA, et al. In the eye of the storm: Immune-mediated toxicities associated with CAR-T cell therapy. Hemasphere. 2019;3:e.

DCME | Dendritic Cell and Monocyte Enumeration, Blood

Dendritic cells play a critical role in both innate and adaptive immune responses. Dendritic cells include two major subsets: myeloid (or conventional) dendritic cells (mDC) and plasmacytoid dendritic cells (pDC).

  • mDC can capture and present antigens to CD4+ T cells and cross-present them to CD8+ T cells. They are also a source of inflammatory cytokines.
  • pDC takes part in priming of anti-viral T cells and is the major source of type I interferons; as such it acts as a primary defense against viremia.

This test enumerates pDC, mDC, and classical monocytes. It can be used as part of the diagnostic assessment of patients suspected of defects in innate immunity, particularly those in monocyte and dendritic cell development, which can manifest in isolation or as part of a broader clinical phenotype. This test has not been validated for the diagnosis of hematologic malignancies.

Additional references for DCME:

  • Bigley V, Cytlak U, Collin M. Human dendritic cell immunodeficiencies. Semin Cell Dev Biol. 2019;86:50-61.
  • Reizis B. Plasmacytoid Dendritic Cells: Development, Regulation, and Function. Immunity. 2019;50:37-50.
  • Vuckovic S, Gardiner D, Field K, Chapman GV, Khalil D, Gill D, et al. Monitoring dendritic cells in clinical practice using a new whole blood single-platform TruCOUNT assay. J Immunol Methods. 2004;284:73-87.