Antibody Testing

Appointments are required.

Test results: 24 hours or less

Test price: $50-$200

  • Multiple COVID-19 Antibody Test Options:

  • See your body's natural response to COVID-19

  • Positive result indicates an individual has mounted an immune response against the virus due to infection or in response to vaccination

  • A positive antibody result may exempt employees from future testing

  • Testing may be covered by private insurance, Medicaid, Medicare and other governmental reimbursers with a prescription from a doctor — otherwise, KSL Diagnostics will provide you with a receipt for your test so that you may submit it to your insurance company for possible reimbursement.  

  • For more information on KSL Diagnostics test pricing and policies, see below or call 1-800-960-1080 to speak with a representative.



  • Post-infection/post-vaccine

  • Measure's body's response

  • May indicate protection

Significance of these tests:

Nucleocapsid Protein COVID-19 Total Antibody Test — SARS-CoV-2 total nucleocapsid antibody assay detects total nucleocapsid antibodies to IgM, IgA and IgG in human serum or plasma specimens. The total antibody assay indicates recent or prior infection. It is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity. Antibodies to SARS-CoV-2 are generally detectable in blood several days after initial infection, although the duration of time antibodies are present post-infection is not well characterized. Individuals may have detectable virus present for several weeks following seroconversion.

Spike Protein COVID-19 Antibody Test — Positive results to antibodies against SARS-CoV-2 are generally indicative of an individual’s current or prior infection with the COVID-19 virus, however, the duration of these antibodies remaining in circulation has not yet been established. These test results should always be considered in the context of a patient’s clinical history, physical examination, epidemiologic exposures and vaccination history before making the final diagnosis.

  • IgM isotype antibodies develop within 5 to 7 days and indicates recent infection.

  • IgG isotype antibodies develop after 10 days and remain in circulation longer. It may indicate past infection or vaccine mediated immune response.

  • IgA isotype antibody development is variable in its response and may indicate It may indicate past infection or vaccine mediated immune response.

Frequently Asked Questions

Why do I need a COVID-19 antibody test?

  • Knowing your vaccination is effective can provide peace of mind. With the recent FDA approval of vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2/COVID-19), testing that quantitatively measures the production of these specific antibodies toward COVID-19 has become clinically valuable in the evaluation of vaccine response. The recently approved mRNA vaccines induce antibody response against the SARS-CoV-2 spike protein. Spike protein antibodies demonstrate potent antiviral activity and correlate with potential immunity. Antibodies against the virus after a natural COVID-19 infection are present; however, these significantly decrease over time. The duration of antibody protection varies from person-to-person. Likewise, antibody levels can determine protection from COVID-19 infection post-vaccination. The presence of antibodies in both cases may indicate protection against severe course of infection or reinfection.

What makes KSL's antibody testing special?

  • KSL offers a NYSDOH-approved test for measurement of antibodies to spike or nucleocapsid proteins.

  • Recognizing the need for tests to determine immune response post-infection or post-vaccination, KSL has designed and developed its highly accurate, isotype-specific IgG, IgM and IgA chemiluminescence immunoassay against the COVID-19 spike protein.

  • Many COVID-19 antibody tests are not valid for testing vaccine effectiveness due to targeting the wrong proteins or suffering from poor sensitivity and specificity. KSL’s COVID-19 antibody tests provide peace of mind, detecting an immune response in both vaccinated (spike protein test) and previously COVID-19 infected individuals (nucleocapsid test).

What are COVID-19 antibodies?

  • Antibodies are one way an individual’s immune system fights infections. People with a healthy immune system develop antibodies against COVID-19 virus shortly after infection. These antibodies are detectable by laboratory tests after about one week after initial infection. In most people, the antibodies clear the COVID-19 infection after about two weeks. While the antibodies are detectable later than the virus, they may help establish the initial diagnosis of a symptomatic patient and offer additional benefits such as indicating an individual’s resistance to the virus and reinfection — if the virus is no longer detectable, these people present a minimal risk of spreading the virus.

What can my COVID-19 test results tell me?

  • Consult this table for basic interpretation of results. This is a guide. Please consult your healthcare provider assistance with your diagnosis and more detailed information.

How much does the test cost and who pays for it?

  • COVID-19 Antibody Testing is for isotype-specific IgG, IgM and IgA COVID-19 spike protein (chemiluminescence, $150) and nucleocapsid total antibody (ELISA, $50), or both tests ($200). Testing may be covered by private insurance, Medicaid, Medicare and other governmental reimbursers. If you have specific questions, please call KSL at 1-800-960-1080 to speak with a representative.

Does insurance cover this test?

  • Insurance will generally cover testing for patients with a prescription from a doctor.

Are these tests approved by FDA?

  • The COVID-19 tests currently offered by KSL are approved by FDA through Emergency Use Authorization (EUA).



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  • Guo, L., Ren, L., Yang, S., Xiao, M., Chang, D., Yang, F., et. al. (2020). Profiling early humoral response to diagnose novel coronavirus disease (COVID-19). Clinical Infectious Diseases.

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