COVID-19 Antibody FAQs

Now Offering COVID-19 PCR and Antibody Testing. Learn More


How long after symptoms should I get the COVID-19 PCR Test?

Once symptoms appear, typically a person will start shedding the virus within a few days, so a PCR test within a few days of symptom onset is appropriate.
If symptoms do not appear, it is harder to determine when the best time to get a PCR test but in general, 1-2 weeks after suspected exposure is a general guideline.  

If you have had symptoms but are recovering recently, a PCR test may still be appropriate because many people shed the virus for several days or even weeks after symptoms start to dissipate.

If I don't have symptoms, is a PCR test still appropriate?

Yes, but not always.  If you don’t have symptoms because you think you had it and recovered, a PCR test may not be appropriate, although antibody testing might.  If you don’t have symptoms, but think you may have been exposed to the SARS-CoV2 virus, a PCR test will help determine if you are infected, regardless of symptoms. 1-2 weeks after suspected exposure is a general guideline on when to get tested, if you are asymptomatic.

How is the PRC test done?

A swab of the nasal-pharyngeal area will be taken by a laboratory professional in a drive-thru setting.  This is the area near the soft palate of your throat (part of your respiratory tract) where viral particles are shed during an active infection.

What is the COVID-19 Antibody Test?

The COVID-19 Antibody test can detect whether you have been exposed to the virus and whether your body has developed antibodies, suggesting you are immune to the virus causing COVID-19. If you have antibodies to the virus that causes COVID-19, it is unlikely that you will spread the disease, particularly if you are asymptomatic.

Does the antibody test diagnose whether I am actively infected with the virus?

No, the antibody test does not necessarily tell you if you are currently infected but it will tell you if you have been infected in the past and are possibly immune to the virus. However, the timing of active infections and antibody production can potentially overlap. 

The PCR test (performed via nasal or throat swab) is the CDC test used to diagnose active infections. If you believe you have an active infection and are experiencing symptoms, you should contact your local health department or a healthcare provider to seek appropriate medical attention. 

Does the antibody test correlate with the severity of the disease?

No.  In fact, the result may indicate you were infected with the SARS-CoV2 virus even if you showed no symptoms whatsoever.  A person who was hospitalized in critical condition and a person who had barely a slight cough could both show antibodies to this virus.  It had nothing to do with the severity of the disease.

In fact, this test does NOT tell you if you are currently infected with the virus – it only tells you if your body has manufactured antibodies to this virus, which suggests a past (but possibly, current) infection.

Who should be tested for antibodies?

Everyone is a candidate for the COVID-19 antibody test. It's important to know your own risk factors (whether you're immune) before we open up the country. 

The antibody test should be performed on individuals with no symptoms. If you had a COVID-19 PCR diagnostic test done recently and it was positive for an active infection, you should wait at least 3 weeks from the onset of symptoms. 


What do the results for the antibody test tell me?

Positive or Negative IgG/IgM results can indicate recent or past infection and potential immunity, arming you with information to help make informed decisions about returning to work or daily activities. 

How long after exposure should this antibody test be done?

Evidence suggests that IgM antibodies against the SARS-CoV2 virus will be detectible in blood serum around 3-5 days after the onset of symptoms (if symptoms occur), which would typically be about 12 days after exposure.

IgG antibodies are a better, more specific indicator of infection with the SARS-CoV2 virus than IgM and will appear about 14 days after symptom onset, which would be about 3 weeks after exposure to the virus. So, we recommend waiting at least 3 weeks. 

How accurate is antibody testing?

When this antibody test is measured against a reference material that is known to be positive for SARS-CoV2 on a cohort of 220 samples, the data shows:

For IgG - specificity = 100%, sensitivity = 97.2%

For IgM - specificity = 100%, sensitivity = 87.9%

Sensitivity is the ability of a test to correctly classify a person as having antibodies to SARS-CoV-2 – thus quantifying false negatives.

Specificity is the ability of a test to correctly classify a person as not having antibodies to SARS-CoV-2.

In other words, sensitivity is the true positive rate, also considered the probability of detection.

Specificity is the true negative rate, also considered the number of healthy people who are correctly marked antibody-free.

Is this antibody test FDA approved?

The SARS-CoV-2 antibody detection kits used by SpectraCell have received FDA Emergency Use Authorization.

The primary governing body for labs is CLIA (Clinical Laboratories Improvement Amendments) which consist of federal standards that clinical labs must follow to assure validity, reliability and quality assurance. We are, of course, a certified CLIA laboratory and we can include documentation about our CLIA certification. But note, that our antibody test IS validated, which means it is tested against a known positive or negative sample. There has been a lot of press about inaccurate antibody kits, but those tests were generally for on-the-spot results and self-collection. The test antibody test we are offering is drawn via venipuncture (so, NOT self-collection). These immunoassays are validated against known reference samples. 

What should I expect at my appointment for on-site testing at SpectraCell Labs??

PCR (Nasal Swab) Testing:

SpectraCell recommends that you arrive at your appointed time wearing a face-covering/mask. Follow any signage for PCR (nasal swab) drive-thru testing. 

You will need to present identification (such as a valid driver's license). Once verified, a certified laboratory technician will administer the nasal swab test and provide your receipt. Results for the PCR (nasal swab) test will be securely emailed within 24-48 hours to the email address provided when purchasing your test online. 

Antibody Testing:

When you arrive at SpectraCell Laboratories at 6030 North Course Drive in Houston, you will see the main entrance to the lab. This building is located behind the SpectraCell office building located at 10401 Town Park Dr.  Follow any signage that facilitates testing in the midst of social distancing measures. A greeter will verify your appointment time and provide instructions. You will be directed where to park and you will remain in your car until you are notified that we are ready for you. There should be minimal wait time if you have made an appointment. You will need to present identification (such as a driver’s license). If you have Traditional Texas Medicare or Texas Medicaid insurance, please present your card so that a photocopy can be obtained. When it is your turn for your blood draw, laboratory personnel will show you to an area where phlebotomy services are set up.  

This is a non-fasting test, so no unusual preparation is needed.  

A phlebotomist - a certified medical professional experienced in drawing blood - will obtain one (or more, depending on if other labs are to be drawn) tubes of blood via venipuncture (drawn via a vein, not a finger stick).  

Results for the COVID-19 test will be emailed to you within 24-48 hours to the email address you provided when purchasing your test. 

Since you will be having blood drawn via venipuncture for this test (blood draw is included in the price), you may wish to consolidate your visit with other tests offered at SpectraCell that require venipuncture. It is standard to charge a fee for having blood drawn by a certified phlebotomist but since you will be having blood drawn for COVID-19 antibody testing, the blood draw fee for any other tests from SpectraCell would be waived.

How soon will results be available?

PCR Testing: 48-72 hours

Antibody Testing: 24-48 hours 

What can I do to improve immunity?

The only way to improve immunity to this specific virus is to either (1) be exposed to the virus or (2) get an effective vaccine.  Obviously, being exposed to the virus can be dangerous.  Plus, without antibody testing, you may never know if you were exposed because you could be one of the people who were infected with SARS-CoV2 but were not symptomatic, or you may have had symptoms but are unsure if they were caused by something else.   And, as of April 2020, no vaccine is available.

However, there is a lot you can do to improve immune function.  Immune function is the ability of your immune system, particularly the white blood cells called lymphocytes, to effectively ramp up and fight things that threaten us, biologically speaking.  Strong immune function means adaptability – because we want our immune cells to adapt to the environment accordingly.  For example, if there is a virus infecting us, we want our immune cells to adapt by fighting that virus and building antibodies against it.  (We want it to do the same with bacteria pathogens as well.)  So immune function precedes immunity

What can I do to improve immune function?

The first step to improve immune function is to quantify it.  One widely researched and well established method to quantify immune function is an assay called lymphocyte proliferation – which is a test in which white blood cells are prompted to grow in order to measure how strong they can respond.

After you quantify immune function, it can be improved by targeted nutrient repletion.  Immune function is largely dependent on the micronutrients available for immune cells to do their job.   Here is a classic example:  vitamin D deficiency lowers immune function.  That is because our cells (lymphocytes) use vitamin D to regulate the highly orchestrated and uber-precise immune response to pathogens.  So if a person is deficient in vitamin D, their immune response may be weaker.

Dozens of nutrients affect immune function.  Making sure there is adequate nutrients available to our cells and targeted repletion of micronutrient deficiencies is a giant step toward improving immune function, which ultimately helps us fight infections like COVID-19.

For more details on the interaction of micronutrients and viral infection, download our (viral wheel).

Where can I find a simple list of terms related to COVID-19?

Much of the terminology for COVID-19 can be confusing.  Download this simple one-page glossary for concise definitions of COVID-19 related terms.

How does this test compare to other antibody tests on the market?

We cannot speak to the quality of testing offered by other companies.  But we can assure you that SpectraCell is a CLIA-certified lab which means it adheres to strict guidelines set forth by the Clinical Laboratory Improvement Amendment Act of 1988, which are United States federal regulatory standards set forth to ensure the quality of clinical lab testing.  SpectraCell is experienced in immunoassay testing (the type of testing done for COVID-19 antibodies), we have dedicated lab personnel experienced in specimen handling and collection, and we validate the testing kits prior to implementation. All the quality control measures SpectraCell follows for its high complexity assays extends to the COVID-19 antibody testing as well.

Currently, at home antibody testing for the virus that causes COVID-19 is not available. This is NOT an at-home test. It is performed by SpectraCell personnel.

COVID-19 Testing for International Travel

What is the meaning of 'Complete Nucleic Acid Testing within 3 days"?

Nucleic Acid Testing, also known as RNA, PCR, or molecular testing is the most common method for diagnosing an existing infection such as SARS-CoV-2. 

This is the type of test required for international travel. If the country you are traveling to requires 'complete nucleic acid testing within 3 days' prior to boarding your flight, this means you must provide results (certificate) of a negative nucleic acid test within 3 days of departure. This applies to direct flights or connecting flights from the US to your destination. 

Example: If you are traveling to China on September 19, the date of your COVID-19 test report (certificate) should be between September 16 - September 19. 

When should you take the test?

Different countries/cities have different requirements. We advise you to contact your local embassy/consulate to determine what those provisions are before scheduling an appointment.