Kephera KDx COVID-19 Antibody Test

Would you like to find out if you were previously infected with COVID-19 prior to being vaccinated? Our test will tell you.

About the Test

Kephera’s antibody test is an enzyme-linked immunosorbent assay (ELISA) to detect the presence of COVID-19 (aka SARS-CoV-2) antibodies in serum or plasma. The presence of these antibodies indicates prior exposure to COVID-19 whether you had symptoms or not. The test does not diagnose an active infection.  Typically, you will develop antibodies within one to two weeks after initial infection.  It is not yet clear how long antibodies continue to be detectable in people who have been infected though current data suggests at least a few months if not more.

  • Informs you whether you have previously been infected with COVID-19, regardless of whether you had symptoms or not
  • Not a diagnostic test for an active infection
  • This is a blood test
  • Available to anyone – all you need is a doctor’s prescription for the test
  • Turnaround time: less than 48 hours
  • Results by email, fax or phone
  • Check if you are qualified for this test here

Order The Test

Consult your Doctor

Get Blood Drawn and Shipped

Get Results in 48 Hrs of Receipt

Test Order Instructions:

  1. Check if you are qualified for the test.
  2. Download the Test Requisition Form.
  3. Get the test requisition form signed by your physician.
  4. Submit payment for the test ($45 USD). Please indicate the patient’s full name, email, and phone number in the description section of the payment form.
  5. Set up an appointment at a local lab or hospital for a blood draw:
    • Either a serum or an EDTA plasma sample is acceptable.
    • The lab must send the sample directly to Kephera Diagnostics along with your Test Requisition Form.
  6. You will receive your test results within 48 hours after Kephera has received your blood sample.

Kephera Diagnostics can bill Medicare for the test — please provide a copy of your Medicare card together with the test requisition form.

Kephera Diagnostics is not able to bill insurance providers at this time, but you will be provided with an itemized receipt
that you can submit to your insurance company for reimbursement.

How it Works

The KDx COVID-19 antibody test detects antibodies to the virus using a method called ELISA, for Enzyme-Linked Immunosorbent Assay.  The ELISA detects two kinds of antibodies, IgG and IgM.  IgM antibodies are usually made by the body within several days to a week after infection, and slowly disappear in the succeeding weeks.  Within about two weeks after infection, IgG antibodies begin to appear in the blood, with titer increasing over time, then possibly decreasing over a period of months. Antibodies typically protect you from infection; however, it is not yet known how well and how long antibodies to COVID-19 might protect an individual from being re-infected with the virus.


Why are COVID-19 antibody tests performed?

  • A COVID-19 antibody test can detect if a person has antibodies to the SARS-CoV-2 virus.   
  • A COVID-19 antibody test is able to help identify individuals who may have been infected with COVID-19 whether symptoms have developed or not.  
  • Typically, antibodies start developing within 1 to 3 weeks after the initial infection. 

Should I get tested?

This test may be right for you if you:

  • Have had or suspect you have had COVID-19 in the past.
  • Have not experienced symptoms consistent with COVID-19 in the past 14 days; please check COVID-19 symptoms information on the CDC website.
  • Have not experienced a fever in the past 24 hours.

This test may NOT be right for you if you:

  • Have been diagnosed with COVID-19 or were directly exposed to the virus in the past 14 days.
  • Have experienced symptoms consistent with COVID-19 in the past 14 days.
  • Are feeling sick or have had a fever within the last 24 hours.
  • Have a condition that weakens your immune system.

What does the test result mean?

COVID-19 antibody test results could be: 

  • Positive. A positive test result means you have COVID-19 antibodies in your blood, which indicates past infection with the virus. It’s possible to have a positive test result even if you never had any symptoms of COVID-19. As with all tests, false-positive results sometimes occur, but this happens rarely.  
  • Negative. A negative test result means that no COVID-19 antibodies were detected, so you were most likely not infected with the COVID-19 virus in the past. However, because it takes at least a week and sometimes longer for antibodies to develop, false-negative test results can happen if the blood sample is collected too soon after your infection started.  In this case, a blood sample drawn several weeks later is likely to be positive. 

What does it mean if I test positive in an antibody test for COVID-19?

  • A positive test means that you were infected with SARS-CoV-2 virus previously.  It does not indicate whether you are still infected or not, or whether you can transmit the virus to others. 

Do I have immunity to COVID-19 if my antibody test result is positive?

  • The presence of antibodies to the SARS-CoV-2 virus that causes COVID-19 may provide protection against the virus. However, it is not clear how long the protection will last.  
  • In general, people who have tested positive for antibodies to the SARS-CoV-2 virus should not assume that they are immune from contracting COVID-19 again. Scientists are attempting to determine if antibodies provide some immunity to the SARS-CoV-2 virus.  However, scientists are not certain about the level of protection or how long immunity will last. To help prevent spreading the virus, follow the CDC guidelines: wash your hands often, avoid close contact, avoid crowds and poorly ventilated places, wear a mask over your nose and mouth, cover coughs and sneezes, and clean and disinfect frequently touched surfaces often. 

How should I prepare for the COVID-19 antibody test?

  • Consult your doctor, who will need to provide you a prescription for the test. Next, go to a blood drawing station or hospital to have your blood drawn. 

What is the procedure for the COVID-19 Antibody test?

  • You will have your blood drawn by a health care professional, by venipuncture (a blood sample will be taken from a vein in your arm). The sample will be sent to our lab for testing. We will run our COVID-19 Antibody Test on your blood sample to determine whether you have developed antibodies against the COVID-19 virus. Typically, you will receive the test result in 48 hours.  

How can I get doctor’s prescription?

  • Print our test requisition form and contact licensed physicians (MD, DO), NPs, PAs, and NDs with active NPI numbers. Bring your test requisition with you, make sure physician fills the test requisition.  

Kephera Diagnostics is a CLIA (Clinical Laboratory Improvement Amendments) licensed laboratory that excels in moderate and high-complexity diagnostic testing. Our dedicated team of scientists are experts in the field of infectious diseases. Through innovative research and collaboration with public health institutions and medical researchers Kephera Diagnostics provides vital testing for patients and healthcare providers. Kephera Diagnostics is HIPAA compliant.

The KDx COVID-19 Antibody Test has not been reviewed by the FDA.