Testing and Laboratory

PCR Testing Guidance

Antigen Testing Guidance and Recommendations

 

  • VDH Algorithm for Evaluating Non-Critical Infrastructure Workers with COVID-19 Symptoms or Exposures 
    • 1-pager: English (4/26 - translations pending)
    • 3-pager: English (4/26 - translations pending)
  • VDH Algorithm for Evaluating a Child with COVID-19 Symptoms or Exposures 
    • 1-pager: English (4/26 - translations pending)
    • 2-pager: English (4/26 - translations pending)
  • VDH Viral Test Results
    • English (3/12/21 - translations pending)
  • VDH Notify Your Contacts
    • English (4/26 - translations pending)
  • VDH Living with Someone with COVID-19
    • English (3/11/21 - translations pending)
  • VDH COVID-19 General FAQs
    • Testing for COVID-19 questions are located under the “COVID-19 Basics” and “Healthcare Providers” sections. For more information on at-home testing, search for “over the counter,” and view the question in the “Testing for COVID-19” section.

Step 1: Know Who to Test.

These people should get tested to diagnose COVID-19 infection:

  • People with symptoms of COVID-19, regardless of their COVID-19 vaccination status
    • Children have similar symptoms as adults, but generally have milder illness. For more information on the clinical presentation and course among children, see Information for Pediatric Healthcare Providers. A syndrome associated with COVID-19 has been described called multisystem inflammatory syndrome in children (MIS-C). Patients aged <21 years might have fever, laboratory evidence of inflammation, and evidence of clinically severe illness with multisystem organ involvement, requiring hospitalization. Healthcare providers should immediately report any patient who meets the MIS-C case definition to the local health department. With symptoms similar to MIS-C, multisystem inflammatory syndrome in adults (MIS-A) might also occur in adults aged 21-50 but is very rare.
  • People who have had close contact with someone with COVID-19 
    • It is best to test a close contact immediately upon identification; if the test is negative,  the close contact should be tested again 5-7 days after last exposure. 
    • Individuals who are fully vaccinated or who have recovered from COVID-19 in the past three months do not need to be tested following close contact with someone with known COVID-19 as long as they remain asymptomatic and do not live or work in a congregate setting, healthcare facility, dormitory residence, or high-density workplace. People who live or work in these settings should still get tested after an exposure.
      • Fully vaccinated means 2 weeks or more have passed since getting the second dose of a two-dose vaccine, or 2 weeks or more have passed since getting 1 dose of a single-dose vaccine. If you have a condition or are taking medications that weaken your immune system, you may not be fully protected even if you are fully vaccinated. Talk to your healthcare provider. Even after vaccination, you may need to continue taking all precautions.
  • People who have taken part in activities that put them at higher risk for COVID-19 because they cannot physically distance as needed, such as attending large gatherings or being in crowded settings
  • People who are planning to travel or who have recently returned from travel with some exceptions for fully vaccinated people
  • People who plan to visit people at high risk of developing severe COVID-19
  • People who have been asked or referred to get testing by their healthcare provider or the health department
  • People without symptoms of COVID-19 who have no known exposures to COVID-19 but wish to help public health officials understand how many people are infected (surveillance testing) 

Counsel your patient on CDC’s ‘3 Key Steps to Take While Waiting for Your COVID-19 Test Result.’ 

Screening testing for people without COVID-19 symptoms and without known exposure to someone with COVID-19 is another important tool to identify cases and prevent the spread of COVID-19. Screening testing should be considered for these people:

  • Racial and ethnic minority groups and other populations disproportionately affected by COVID-19
  • Teachers and staff in K-12 schools and/or childcare settings
  • Students, faculty, and staff at institutions of higher education (including community colleges and technical schools)
  • Workers in high-density worksites or worksites with large numbers of close contacts to co-workers or customers (e.g., restaurant workers, transportation workers, grocery store workers)
  • Government workers with public interactions as part of their duties (e.g., post office workers)
  • First responders (e.g., police, fire, EMT) and healthcare personnel
  • Residents and staff in congregate settings such as shelters serving the homeless and correctional and detention facilities or residential settings such as nursing homes or those serving persons with disabilities; workplaces that provide congregate housing (e.g., fishing vessels, offshore platforms, farmworker housing or wildland firefighter camps); military training facilities (e.g., barracks); dormitories at educational institutions
  • Persons who recently traveled, either domestic or international with some exceptions for fully vaccinated people, and those who attended mass gatherings
  • Patients in healthcare settings
  • Specific age groups (e.g., young adults) for whom increases have been documented early as incidence rises, especially in communities with substantial or high transmission

Fully vaccinated people with no COVID-19-like symptoms and no known exposure should be exempted from routine screening testing programs, if feasible.

Step 2: Collect specimens safely. 

Verify with your diagnostic laboratory which specimens are appropriate for the tests they offer. Follow the directions on the laboratory’s test menu for specific specimen collection instructions, submission forms, and shipping requirements.

For initial diagnostic testing for SARS-CoV-2, collecting and testing one of the following upper respiratory specimens is typically recommended (see table below). To conserve PPE, consider diagnostic tests that use specimens that can be collected using minimal PPE. These include a patient self-collected nasal swab. VDH developed a brief video: Patient Self-Collecting Nasal Swab for COVID-19. This VDH infographic is a resource for patients about what to expect when they have a nasopharyngeal (NP) swab collected for a COVID-19 test. The New England Journal of Medicine also has a brief video: How to Obtain a Nasopharyngeal Swab Specimen

The Virginia Emergency Support Team (VEST) has coordinated with Amazon to provide a portal for healthcare professionals to purchase PPE in varied amounts and types at a reasonable price. 

Table 1. General guidance for the preferred types of specimen collection*

Specimen Type PPE Equipment Instructions
Nasopharyngeal (NP) swab collected by healthcare professional (HCP) N95 or higher-level respirator (or face mask if a respirator is not available), eye protection, gloves, and a gown Flocked, synthetic fiber mini-tip swabs with plastic or wire shafts Tilt the patient's head back slightly so that nasal passages are more accessible. Insert minitip swab through the nostril parallel to the palate (not upwards) until resistance is encountered or the distance is equivalent to that from the nostril to the ear of the patient, indicating contact with the nasopharynx.  Gently rub and roll the swab. Leave swab in place for several seconds to absorb secretions. Slowly remove swab while rotating it.
Nasal mid-turbinate swab (Deep Nasal Swab) collected by HCP N95 or higher-level respirator (or face mask if a respirator is not available), eye protection, gloves, and a gown Flocked tapered swab Tilt patient’s head back 70 degrees. While gently rotating the swab, insert swab less than one inch (about 2 cm) into nostril (until resistance is met at turbinates). Rotate the swab several times against nasal wall and repeat in other nostril using the same swab.
Nasal mid-turbinate swab (Deep Nasal Swab) collected by patient while medically-supervised with HCP located > 6 feet away Standard precautions, gloves, universal source control (e.g., facemask or cloth mask) at all times in healthcare facilities Flocked tapered swab Patient should tilt head back 70 degrees. While gently rotating the swab, insert swab less than one inch (about 2 cm) into nostril (until resistance is met at turbinates). Rotate the swab several times against nasal wall and repeat in other nostril using the same swab.
Nasal swab (anterior nares) collected by HCP N95 or higher-level respirator (or face mask if a respirator is not available), eye protection, gloves, and a gown Use flocked or spun polyester swab Insert the swab at least 1 cm (0.5 inch) inside the nostril (naris) and firmly sample the nasal membrane by rotating the swab and leaving in place for 10 to 15 seconds. Sample both nostrils with the same swab.
Nasal swab (anterior nares) collected by patient while medically-supervised with HCP located > 6 feet away Standard precautions, gloves, universal source control  (e.g., facemask or cloth mask) at all times in healthcare facilities Use flocked or spun polyester swab Patient should insert the swab at least 1 cm (0.5 inch) inside the nostril (naris) and firmly sample the nasal membrane by rotating the swab and leaving in place for 10 to 15 seconds. Sample both nostrils with the same swab.
Nasopharyngeal wash/aspirate or nasal wash/aspirate (NW) collected by HCP N95 or higher-level respirator (or face mask if a respirator is not available), eye protection, gloves, and a gown Use catheter attached to suction apparatus Have the patient sit with head tilted slightly backward. Instill 1 mL-1.5 mL of non-bacteriostatic saline (pH 7.0) into one nostril. Insert the tubing into the nostril parallel to the palate (not upwards). Catheter should reach depth equal to distance from nostrils to outer opening of ear. Begin gentle suction/aspiration and remove catheter while rotating it gently. Place specimen in a sterile viral transport media.
Saliva collected by HCP N95 or higher-level respirator (or facemask if a respirator is not available), eye protection, gloves, and a gown Leak-proof screw cap container Collect 1-5 mL of saliva in a sterile, leak-proof screw cap container.
Saliva collected by patient while medically-supervised with HCP located > 6 feet away Standard precautions, gloves, universal source control (e.g., facemask or cloth mask) at all times in healthcare facilities Leak-proof screw cap container Collect 1-5 mL of saliva in a sterile, leak-proof screw cap container.

*Oropharyngeal (OP) swabs should only be collected if nasal or NP is not available. HCP collecting OP swabs should wear the same PPE as used when collecting NP swabs. Testing lower respiratory tract specimens is also an option. For patients who develop a productive cough, sputum can be collected and tested when available for SARS-CoV-2. However, the induction of sputum is not recommended. Under certain clinical circumstances (e.g., those receiving invasive mechanical ventilation), a lower respiratory tract aspirate or bronchoalveolar lavage specimen should be collected and tested as a lower respiratory tract specimen.

For more information, see the section on Respiratory Specimen Collection in CDC’s Interim Guidelines for Collecting and Handling of Clinical Specimens for COVID-19 Testing.

Step 3: In general, send specimens to commercial laboratories.

In general, healthcare providers should send specimens for COVID-19 testing to commercial, private, or hospital laboratories. VDH recommends healthcare providers work with laboratories that use viral tests granted an Emergency Use Authorization (EUA) by FDA, or use viral tests offered under the policies in FDA’s Policy for COVID-19 Tests. Healthcare providers should use caution when working with high complexity laboratories that are performing tests that have not received an EUA. In this instance, it is suggested that the healthcare provider obtain performance data from the manufacturer or laboratory. 

Many community sites conduct specimen collection and perform point-of-care (POC) tests or send specimens to a private or reference laboratory for testing. VDH currently partners with select Walgreens stores to provide free COVID-19 testing. To find a site for your patient, visit Virginia COVID-19 Testing Sites. Each site may have different policies and procedures for testing and billing.

At-home testing can also be considered if testing at a local healthcare facility or community testing event is not available, or for homebound people. There are two types of at-home testing -- kits where a specimen (nasal swab or saliva) is collected at home, packaged, and sent to a lab for testing, and those where a specimen is collected AND tested at home.   Home testing or collection kits come with printed instructions on specimen collection, or this material may be available online.  As of this writing, there are many home PCR-based specimen collection kits (with the sample sent to a reference lab for testing), one non-prescription PCR-based test designed to be done at home, and one non-prescription antigen kit that is meant for home testing.  Test protocols and/or requirements vary by manufacturer, and some  mandate a health assessment. For more information on at-home testing, visit VDH’s table on COVID-19 at-home tests here or the website CDC At-Home Testing.

In certain situations, testing at Virginia’s public health laboratory (Division of Consolidated Laboratory Services or ‘DCLS’) or partnering laboratories might be indicted. These situations include testing to confirm the presence of an outbreak, or testing by whole genome sequencing.  Clinicians may request public health testing for these scenarios by contacting their local health department. Submitters using public health testing must be willing and capable of collecting and packaging specimens, and either delivering them to a Division of Consolidated Laboratory Services courier site or shipping them via commercial courier (e.g., FedEx).

Step 4: Test patients using a diagnostic test for COVID-19 and interpret the findings.

Viral tests (molecular-based or antigen-based tests) are recommended to diagnose acute infection. These tests check samples from the respiratory system or saliva to determine whether SARS-CoV-2 virus is present.

PCR Tests

Molecular-based tests, such as PCR tests, detect the virus’s genetic material.

Table 2. Molecular-based test (e.g., PCR) result interpretation for symptomatic and asymptomatic persons

Test Result Person being Tested
  Symptomatic Person

(test as close to symptom onset as possible and as recommended by manufacturer)

Asymptomatic Person with Close Contact to a known COVID-19 case Asymptomatic Person without Close Contact to a known COVID-19 case
Positive
Negative
  • SARS-CoV-2 RNA was not detected
  • Recommend isolation based on exposure and symptoms§
  • Consider re-testing if suspicion of COVID-19 still exists, despite negative COVID-19 test
  • SARS-CoV-2 RNA was not detected
  • Recommend isolation based on exposure and symptoms§
  • Consider re-testing if suspicion of COVID-19 still exists, despite negative COVID-19 test
  • SARS-CoV-2 RNA was not detected
  • Follow situation-specific infection prevention measures
  • Negative test does not rule out the potential for future infection

§ If the person had a known exposure to someone with COVID-19, the person should continue to quarantine until 14 days after the last known exposure. VDH and CDC continue to recommend a 14-day quarantine period as the safest option. If the person cannot stay home for the full 14 days after exposure and does not have symptoms, the person may end quarantine earlier. Counting the date of last exposure as Day 0, the person may end quarantine  after Day 10 without testing, or after Day 7 with a negative PCR or antigen test performed on or after Day 5. If the person does not stay home for the recommended 14 days, the person should continue monitoring for symptoms and follow all other recommendations (e.g., wear a mask, practice physical distancing, and wash hands often) for the full 14-day period after the last exposure. If the person did not have a known exposure to someone with COVID-19, the person should isolate until at least 24 hours after symptoms resolve (if symptomatic), or follow protective measures in place in the community (if asymptomatic). If the person has recovered from COVID-19 and does not develop new COVID-19 symptoms within 3 months or has been fully vaccinated for COVID-19, the person is not required to quarantine after close contact with someone with COVID-19, as long as the person does not develop symptoms, and does not live or work in a congregate setting, healthcare facility, or high-density workplace. Healthcare personnel (HCP) who are fully vaccinated for COVID-19 do not need to quarantine after a workplace or community-associated exposure as long as they do not have any symptoms and do not have underlying immunocompromising conditions (e.g., organ transplantation, cancer treatment). HCP should continue to follow all travel recommendations. For additional details about COVID-19 vaccination for people living or working in healthcare settings, see here. The person should still watch for symptoms for 14 days and continue to wear a mask, practice physical distancing, avoid crowds, and wash their hands often. See exceptions to masking and physical distancing for fully vaccinated people here.
Close contact
A negative molecular test result for SARS-CoV-2 means that at the time of collection, RNA from this virus was not present in the specimen at or above the limit of detection.

  • A positive molecular test result indicates current infection, regardless of vaccination status for COVID-19.
    • Caveats: A positive molecular test does not necessarily mean viable virus is present (i.e., that the person is infectious). Viral RNA can persist in the respiratory tract. Immune competent persons with a previously positive molecular test who have a repeat positive molecular test within 3 months are not subject to re-isolation provided they meet the symptom-based or time-based criteria. Persons who are severely immunocompromised should consult with their healthcare provider in addition to meeting the test-based criteria. These persons might have prolonged viral shedding and be infectious longer than 10 days after onset (or specimen collection date). For more information from CDC about persistently positive molecular results, see here
  • A negative molecular test result indicates SARS-CoV-2 RNA was not detected at the time of testing.
    • Caveats: Virus might not have been detected because the person is not currently infected, the virus caused the illness, but is no longer detectable or present in the upper respiratory tract, or an inadequate specimen was collected. For symptomatic people with a negative molecular test, clinician judgment is also important. If the clinician feels COVID-19 is the most likely diagnosis, the patient should be treated accordingly. While uncommon, false negative molecular tests occur.
  • For at-home testing, an invalid result or a test error indicates that the test did not work properly. Please refer to the instructions in the package insert and contact the manufacturer, if needed, for assistance.

For patient handouts about viral tests results and next steps, see the ‘VDH COVID-19 Viral Test Results Infographic.’

Antigen Tests

An antigen test is another type of viral test. It detects the presence of SARS-CoV-2 nucleocapsid protein antigen. Antigen is generally detectable in upper respiratory specimens during the acute phase of infection. Antigen tests are generally less expensive than molecular tests and can be used at the point of care; however, they are generally less sensitive than molecular tests, and molecular tests remain the “gold standard” for detection of SARS-CoV-2.

If using an antigen test, select one that has received an Emergency Use Authorization (EUA) from the FDA and ensure proper interpretation of results for accurate clinical management of patients with suspected COVID-19, or for identification of potentially infected persons when used for screening. As of this writing, more than 15 antigen tests have received FDA EUAs. Most of these are CLIA-waived prescription items that have a point-of-care test option.  Some are prescription items in which a specimen is collected and tested at home; others are available as  over-the-counter products without a prescription. Several tests are meant for use in a medium or high-complexity lab. Most antigen tests have language in their EUAs stating the test is meant for use in symptomatic individuals who are suspected of having COVID-19.  However, some tests are indicated for use in people with or without symptoms/signs of COVID-19, or an epidemiologic reason (e.g., exposure to a known COVID-19 case, participating in a large gathering where social distancing was not possible) to suspect the illness.  FDA’s list of antigen tests with an EUA provides details about each test.

Laboratory and testing professionals who conduct diagnostic or screening testing for SARS-CoV-2 with antigen tests must comply with Clinical Laboratory Improvement Amendments (CLIA) regulations. Any laboratory or testing site that intends to report patient-specific test results must first obtain a CLIA certificate and meet all requirements to perform that test. For more information, see the Centers for Medicare & Medicaid Services’ (CMS) summary of the CLIA regulations. For more information from CDC about antigen testing, see here. For more information on antigen testing in Virginia, see the VDH documents Getting Started with COVID-19 Point of Care (POC) Antigen Testing and  Antigen Testing Recommendations

Table 3. Antigen test result interpretation for symptomatic and asymptomatic persons

Test Result Person being Tested
  Symptomatic Person

(test as close to symptom onset as possible and as recommended by manufacturer)

Asymptomatic Person with Close Contact# to a known COVID-19 case Asymptomatic Person without Close Contact# to a known COVID-19 case
Positive
  • Presumptive current infection
  • Prompt isolation while awaiting confirmatory test result
  • Confirm positive result with a PCR test done in a high-complexity CLIA-certified laboratory*
  • Patients with positive confirmatory test should isolate until no longer contagious by time-based strategy
Negative
  • Indicates no antigens were detected; however, amount of antigen in a sample decreases as duration of illness increases, particularly ≥ 5 days after symptom onset.
  • Confirm negative antigen result with a PCR test done in a high-complexity CLIA-certified laboratory
  • Prompt isolation while awaiting confirmatory test result
  • No antigens were detected
  • Close contacts who test negative should  complete 14 days of quarantine.§
  • Obtain COVID-19 PCR test if person develops symptoms
  • Retest close contact 5-7 days after last exposure
  • No antigens were detected
  • No additional case follow-up necessary
  • Reinforce prevention measures

§ If the person had a known exposure to someone with COVID-19, the person should continue to quarantine until 14 days after the last known exposure. VDH and CDC continue to recommend a 14-day quarantine period as the safest option. If the person cannot stay home for the full 14 days after exposure and does not have symptoms, the person may end quarantine earlier. Counting the date of last exposure as Day 0, the person may end quarantine after Day 10 without testing, or after Day 7 with a negative PCR or antigen test performed on or after Day 5. If the person does not stay home for the recommended 14 days, the person should continue monitoring for symptoms and follow all other recommendations (e.g., wear a mask, practice physical distancing, and wash hands often) for the full 14-day period after the last exposure. If the person has recovered from COVID-19 and does not develop new COVID-19 symptoms within 3 months or has been fully vaccinated for COVID-19, the person is not required to quarantine (even after close contact with someone with COVID-19), as long as the person does not develop symptoms and does not live or work in a congregate setting, healthcare facility, or high-density workplace. Healthcare personnel (HCP) who are fully vaccinated for COVID-19 do not need to quarantine after a workplace or community-associated exposure as long as they do not have any symptoms and do not have underlying immunocompromising conditions (e.g., organ transplantation, cancer treatment). HCP should continue to follow all travel recommendations. For additional details about COVID-19 vaccination for people living or working in healthcare settings, see here. The person should still watch for symptoms for 14 days and continue to wear a mask, practice physical distancing, avoid crowds, and wash their hands often. See exceptions to masking and physical distancing for fully vaccinated people here.
# Close contact
* A positive antigen test result in an asymptomatic, unexposed individual should be immediately followed by a PCR test run in a high-complexity CLIA-certified laboratory to verify the positive result. This follow-up specimen should be collected within 24 hours of the original test, if possible, and no more than 48 hours after the antigen test. Specimens collected more than 48 hours after the initial test may lead to discordant results. If the confirmatory PCR is negative on an appropriate specimen collected in the proper time frame, and the individual has remained asymptomatic, the antigen test would be considered a false positive and the individual not counted as a COVID-19 case.
+ While multiple specimen types may be acceptable, if possible, confirmatory tests should be performed using specimens with evidence of the most sensitivity, such as nasopharyngeal or mid-turbinate swabs.

  • A positive antigen result indicates current infection or presumptive current infection.
    • Caveats: False positives can occur, especially in areas of low COVID-19 prevalence. Results should be interpreted in the context of disease prevalence, the test’s performance characteristics and instructions for use, and the patient’s clinical signs, symptoms, and history.
  • A negative antigen result indicates no antigens were detected at the time of testing.
    • Caveats: Studies have shown that antigen levels in some patients who have been symptomatic for more than five days might drop below the limit of detection of the test. This might result in a negative test result, while a more sensitive test, such as a molecular test, might return a positive result. It might be necessary to confirm an antigen test result with a molecular test, especially if the result of the antigen test is inconsistent with the clinical context. When confirming an antigen test result with a molecular test, it is important that the time interval between the two sample collections is less than two days, and there have not been any opportunities for new exposures between the two tests. If more than two days separates the two tests, or there have been opportunities for new exposures between the two tests, the molecular test should be considered a separate test – not a confirmatory test.

For 1-page patient handouts about antigen test results and next steps, see the ‘VDH Antigen Testing Results and Next Steps Handout.’

Cycle Threshold (Ct) Values for PCR Tests

Ct stands for “Cycle Threshold.” Ct is a number generated during a PCR test. The Ct number refers to the number of cycles needed for a sample to grow and cross a cutoff point (threshold) where it changes from negative (not detectable) to positive (detectable).

Ct values and cutoffs differ by test and cannot be compared from one test to another. Some PCR tests also do not use Ct values but use a different value instead to report the test being positive or negative.  Ct values are not meant to be used as a proxy measure of the amount of virus (viral load) a person has.

PCR positive results and the Ct values cannot determine the infectiousness of the person tested. More research is needed to determine the amount of virus necessary to infect someone else. Viral load changes drastically over the course of infection.

For more information on Ct values, refer to the CDC Lab FAQs for Interpreting Results of Diagnostic Tests and the Association of Public Health Laboratories (APHL) resource: ‘Ct Values: What They Are and How They Can be Used.’

Antibody Tests

Serology, or antibody tests, are NOT recommended for making a diagnosis of acute COVID-19 infection. Serology tests identify the body’s immune response to exposure to SARS-CoV-2. These tests could be useful to determine how widespread infection has been in different populations, to identify people with antibodies who can donate plasma, for serosurveys in populations to determine true infection rates, and to learn more about the antibody response to SARS-CoV-2 and its relationship with symptom history. Confirmed and suspected cases of reinfection of the virus that causes COVID-19 have been reported, but remain very rare. For more information, see Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Serologic Testing.

On April 6, 2021 the FDA issued an EUA for the Symbiotica COVID-19 Self-Collected Antibody Test System, the first antibody test authorized for use with home collected dried blood spot samples. Samples collected at home are then sent to a Symbiotica, Inc. laboratory for analysis. This test is available by prescription and provides a qualitative result only for IgG antibodies. To obtain this test, a health history must be completed.

  • A positive antibody result indicates the person might have been infected with the virus at some point in the past. A positive result is also possible if the person has been vaccinated for COVID-19. 
    • Recommendation: Test with PCR or antigen test if clinically indicated. 
    • Caveat: Detection of antibodies does not mean the person is infectious or immune to SARS-CoV-2. A false positive is possible if the test cross-reacts with commonly circulating coronaviruses.
  • A negative antibody result means that antibodies to SARS-CoV-2 were not detected in serum. 
    • Recommendation: Retest if antibody status is needed, or test with PCR or antigen if clinically indicated.
    • Caveat: This could indicate that the person has not been infected, that antibodies had not developed at the time of specimen collection, antibody levels are too low for the test to detect, or the immune system has not mounted a response to the exposure (e.g., because of immunosuppression).

Refer to the ‘VDH COVID-19 Testing Algorithm’ for a visual overview of molecular and antigen testing. Get helpful advice on informing your patients of COVID-19 test results. Provide additional guidance and education to patients with confirmed or suspected COVID-19. 

Refer to the ‘VDH Table of COVID-19 Test Types’ for a comparison chart of frequently asked questions about PCR, antigen, and antibody tests.

Step 5: Report all cases to VDH.

Clinicians should utilize the Confidential Morbidity Portal to report suspected and confirmed COVID-19 cases as soon as they are identified. Please include symptoms and other critical epidemiologic fields, including race and ethnicity, in your report.

VDH has developed a reporting portal specifically for point-of-care (POC) COVID-19 test results. This portal will assist testing sites in meeting the requirement of the CARES Act to report every diagnostic and screening test performed to detect SARS-CoV-2 or to diagnose a possible case of COVID-19 (e.g., molecular, antigen, antibody). This portal allows the rapid entry of person-level test results for positive and negative results, and provides the ability to enter aggregate negative results as necessary for high-volume testing sites. All COVID-19 test results should be reported to VDH within 24 hours. Testing sites should go here to register for the POC Reporting Portal. 

All COVID-19 reports from clinicians or facilities based on point-of-care tests should be reported using the VDH Point-of-Care (POC) Portal, not the Confidential Morbidity Portal. For other reports not involving POC testing, healthcare providers should continue to report patients with suspected or confirmed COVID-19 through the Confidential Morbidity Portal.

Step 6: Educate patients on when it is safe to be around others.

Ending isolation and quarantine: when is it safe for my patients to be around others? 

People with a positive COVID-19 viral test and symptoms may be around others after:

  1. At least 10 days have passed since symptoms first appeared, and
  2. At least 24 hours with no fever without fever-reducing medication, and
  3. Other symptoms have improved.

People with a positive COVID-19 viral test, regardless of vaccination status, but who never had any symptoms may be around others after 10 days have passed since the first positive diagnostic test. In general, retesting for COVID-19 is not recommended for 3 months after the first positive viral test. However, for people who are severely immunocompromised, a test-based strategy for ending isolation could be considered in consultation with an infectious diseases expert.

Close contacts who do not have symptoms and who test negative for COVID-19 on a viral test (PCR or antigen test) should still complete the full 14-day quarantine. VDH and CDC continue to recommend a 14-day quarantine period as the safest option. 

If the person cannot stay home for the full 14 days after exposure and does not have symptoms, the person may end quarantine earlier. Counting the date of last exposure as Day 0, the person may leave home after Day 10 without testing or after Day 7 with a negative PCR or antigen test performed on or after Day 5. If the person does not stay home for the recommended 14 days, the person should continue monitoring for symptoms and follow all other recommendations for the full 14-day period after the last exposure. 

If the person has recovered from COVID-19 and does not develop new COVID-19 symptoms within 3 months, the person might not need to quarantine (even after close contact with someone with COVID-19), but the person should still watch for symptoms for 14 days and continue to wear a mask, practice physical distancing, avoid crowds, and wash their hands often. 

If the person has been fully vaccinated for COVID-19, the person does not need to quarantine (even after close contact with someone with COVID-19), as long as they do not develop symptoms. They should still get tested, but do not need to quarantine if they live or work in a non-healthcare congregate setting, dormitory (or similar high-density housing setting) at educational institutions, healthcare facility, or high-density workplace. Testing in these settings is still recommended because they may face high turnover of residents, a higher risk of transmission, and challenges in maintaining recommended physical distancing.

Healthcare personnel (HCP) who are fully vaccinated for COVID-19 do not need to quarantine after a workplace or community-associated exposure as long as they do not have any symptoms and do not have underlying immunocompromising conditions (e.g., organ transplantation, cancer treatment). HCP should continue to follow all travel recommendations. For additional details, see here.

Fully vaccinated inpatients and residents of healthcare facilities should continue to follow quarantine recommendations after close contact with someone with COVID-19. Healthcare settings include hospitals and long-term care facilities (e.g., nursing homes, assisted living facilities). 

People who are immunocompromised who have been fully vaccinated should talk with their healthcare provider about whether quarantining after close contact exposure is recommended. 

These recommendations are based on what we know about COVID-19 vaccines and protection provided by previous infection at this time and apply to COVID-19 vaccines that have been authorized for emergency use by FDA (i.e., Pfizer-BioNTech, Moderna, and Johnson & Johnson Janssen) and WHO (i.e., AstraZeneca/Oxford). CDC and other scientists continue to research the ability of COVID-19 vaccines to prevent transmission of the virus, but this process takes time. As we learn more, changes could be made to these recommendations.

If the person has been fully vaccinated for COVID-19, the person does not need to get tested before or after travel in the United States or quarantine after U.S. travel if they are traveling in the United States unless their destination requires it. All people who travel internationally should pay close attention to the situation at your international destination before travel should get tested 3-5 days after international travel. The person will still need to show a negative test result or documentation of recovery from COVID-19 before boarding a flight to the United States. If you have been fully vaccinated for COVID-19, you do not need to quarantine after international travel. For additional details, see here.

People who are not required to quarantine after exposure should still watch for symptoms for 14 days and continue to wear a mask, practice physical distancing, avoid crowds, and wash their hands. See exceptions to masking and physical distancing for fully vaccinated people here

For additional information, see CDC’s recommendations here and more information from VDH here.

Additional Information

Retesting

In general, retesting asymptomatic people within 3 months of their initial COVID-19 infection by a viral test is not recommended. People with COVID-19 can have persistently positive PCR tests for many weeks after their infection, even though they are not infectious. Although there have been limited reports of people with confirmed COVID-19 reinfection, the data collected so far indicate that reinfection within 3 months is not likely to occur. For people who are severely immunocompromised, a test-based strategy could be considered in consultation with an infectious diseases expert.

For people who have recovered from COVID-19 but subsequently develop new COVID-19 symptoms within 3 months of their initial infection, retesting can be considered if there is no alternate diagnosis. People who are fully vaccinated for COVID-19, do not have to get tested (even after close contact with someone with COVID-19) as long as they do not develop symptoms and do not live or work in a congregate setting, healthcare facility, or high-density workplace. If a person lives or works in one of these places, they may still need to get tested after an exposure even if they are fully vaccinated. Employees should continue to follow workplace testing procedures if in place. The person should still watch for symptoms for 14 days and continue to wear a mask, practice physical distancing, avoid crowds, and wash their hands. See exceptions to masking and physical distancing for fully vaccinated people here. For additional information, see CDC’s recommendations here and more information from VDH here

Billing and reimbursement

Payment is available to healthcare providers to counsel patients, at the time of COVID-19 testing, about the importance of self-isolation after they are tested and prior to the onset of symptoms. Reimbursement for providers who are eligible to bill CMS for counseling services will be handled using existing evaluation and management payment codes.

The COVID-19 Uninsured Program Portal was launched by the federal government to allow healthcare providers who have conducted COVID-19 testing or provided COVID-19 treatment for uninsured persons on or after February 4, 2020 to submit claims for reimbursement. Providers can access the portal at COVIDUninsuredClaim.HRSA.gov.

Working with employers

VDH does not recommend that employers require test results or a healthcare provider’s note to excuse them from work, qualify for sick leave, or allow for return to work. For more information see the VDH Algorithm for Evaluating Non-Critical Infrastructure Workers with COVID-19 Symptoms or Exposures here and VDH Graphic on Ending Isolation in Non-Healthcare Settings here.

Emerging SARS-CoV-2 Variants

Multiple SARS-CoV-2 variants that cause COVID-19 have been documented during this pandemic. Currently, several variants are circulating globally and in the United States. These new variants seem to spread more easily and quickly than non-variants. Research is ongoing to assess other variant characteristics, such as disease severity, the impact on vaccine-induced immunity, and the impact on diagnostic tests. Most currently available PCR tests will still detect the virus, even if there is a mutation.

The variant that was first identified in the United Kingdom in 2020 (B.1.1.7) has been identified in many U.S. states or jurisdictions, including Virginia. At least one preliminary report suggests the possibility of increased risk of death with this variant, but additional studies are ongoing. The variant that was first identified in South Africa in 2020 (B. 1.351) has also been identified in many U.S. states or jurisdictions, including Virginia. The variant first identified in travelers from Brazil (P.1) has also been found in many U.S. states or jurisdictions, including Virginia. The variants that were first identified in California (B.1.427 and B.1.429) have been identified in many other U.S. states or jurisdictions, including Virginia. VDH continues to work with laboratory partners to study new COVID-19 variants to track their spread and ensure these are detected with the available viral tests. 

Public health recommendations for stopping the spread of COVID-19 will work for all COVID-19 variants. The best way to stop variant strains from developing in the first place is to stop the spread of the virus.

Please ask patients suspected of having COVID-19 about recent travel to and from areas outside the United States with known circulating variant strains. If you diagnose COVID-19 by nucleic acid or antigen test in a person who traveled to one of these areas in the 14 days before symptom onset (or specimen collection, if asymptomatic), please contact your local health department.

For the latest information, see VDH’s Variants of the Virus that Causes COVID-19 and CDC’s About Variants of the Virus that Causes COVID-19​​ and Emerging SARS-CoV-2 Variants.  To see where these variants are being identified in Virginia, visit VDH’s Variants of the Virus Dashboard. To see how commonly variants are being identified in the U.S. and where these variants are being identified, visit CDC’s COVID Data Tracker.

Refresher on useful epidemiology terminology about test performance:

  • Sensitivity: measures the ability of a test to correctly identify persons who have COVID-19. Calculated by:  [a/a+c]*100
  • Specificity: measures the ability of the test to correctly identify persons who do not have COVID-19. Calculated by: [d/b+d]*100
  • Cross-reactivity:        
    • PCR – reagents used for SARS-CoV-2 test react with non-SARS-CoV-2 organisms by either actual lab testing or by theoretical sequence analysis
    •  Antigen – reagents react with related pathogens, high prevalence organisms or normal flora likely to be encountered in a clinical specimen
    • Serology - detection of other related antibodies (e.g., produced by past infection with other coronaviruses) which could produce a false positive result for antibodies to SARS-CoV-2. Researchers (Gorse et. al) estimate that 90% of persons age 50 or older have antibodies to common non-SARS-CoV-2 human coronaviruses HKU1, NL63, OC43, or 229E. 
  • Pretest probability: Probability of a patient having an infection before the test result is known; based on the proportion of people in a community with the disease at a given time (prevalence) and the clinical presentation of the patient.
  • Prevalence: proportion of population that have been infected with SARS-CoV-2.
  • Positive predictive value (PPV): the probability that a person with a positive SARS-CoV-2 test result actually is infected with SARS-CoV-2. Calculated by: [a/a+b]*100. To calculate PPV, disease prevalence must be known or estimated. PPV goes up as disease prevalence increases, and down as prevalence decreases
  • Negative predictive value (NPV): the probability that a person with a negative SARS-CoV-2 test result is not infected with SARS-CoV-2. Calculated by: [d/c+d]*100. To calculate NPV, the disease prevalence must be known or estimated. As disease prevalence increases, NPV decreases, and as prevalence decreases, NPV increases.
    Disease + Disease -
Test + a=true positive b=false positive
Test - c=false negative d =true negative

Page Last Updated: May 5, 2021