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.
Recommended only for patients who meet current clinical and/or epidemiologic criteria defined by federal, state, or local public health directives.
Useful for detection of COVID-19 due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Note: COVID-19 testing is currently available only to clients who have received prior approval. For more information, contact Customer Service at 800-533-1710.
Useful for detection of IgG-class antibodies against SARS-CoV-2, the virus that causes COVID-19.
Neutralizing Antibody Testing
Recommended for identification of convalescent plasma donors after confirmation of past SARS-CoV-2 infection and documenting adaptive immune responses in those undergoing SARS-CoV-2 vaccination.
If SARS-CoV-2 IgG antibody test result is reactive, then SARS-CoV-2 neutralizing antibody (NAb) confirmation will be performed at an additional charge. In addition, if SARS-CoV-2 NAb confirmation test result is positive, then the NAb titer will be performed at an additional charge.
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Neutralizing Antibody, Follow up, Serum (TEST ID: CVNFS)
This test should only be ordered if seropositivity has been demonstrated on a SARS-CoV-2 IgG or total antibody serological test. If SARS-CoV-2 NAb test result is positive, then the NAb titer will be performed at an additional charge.
COVID-19 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:
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 interested as a potential therapeutic option.
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 natural killer (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.
Tocilizumab (TOC) is a recombinant humanized IgG1 kappa monoclonal antibody that targets the interleukin-6 (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.