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.  

Key testing

• COVSQ | Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Spike Antibody, Semi-Quantitative, Serum
  • Provides semi-quantitative detection of serum antibodies against the spike glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19).
  • Aids in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating prior infection and/or vaccination.
  • Useful for the manufacturing of SARS-CoV-2 convalescent plasma units.
• COVTA | Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Nucleocapsid, Total Antibody, Serum
  • Detects antibodies against the nucleocapsid protein, which would only be positive following natural infection. This helps determine whether an individual has been infected naturally at some point in time in the past.

---

Related testing

Key testing

• TBBS | Quantitative Lymphocyte Subsets: T, B, and Natural Killer (NK) Cells, 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.
• 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.
• 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.