Testing, Laboratory, and Therapeutics

Interim COVID-19 Testing Guidance for Healthcare Providers

Test all patients with symptoms consistent with COVID-19.

Rapidly test all patients with COVID-19 symptoms. Testing informs patient management and is a critical first step in identifying and isolating people with COVID-19, quarantining their close contacts, and preventing community spread. 

COVID-19 patients might present with:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle pain or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Nasal congestion or runny nose
  • Nausea or vomiting
  • Diarrhea
  • Atypical presentations have been described

Children have similar symptoms as adults and generally have milder illness. For more information on the clinical presentation and course among children, see Information for Pediatric Healthcare Providers. A new 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 similar symptoms like MIS-C, Multisystem Inflammatory Syndrome in Adults (MIS-A) might also occur in adults aged 21-50 but is very rare. 

Older adults and persons with medical comorbidities might have delayed presentation of fever and respiratory symptoms, and older persons might have new confusion, delirium or falls. 

Clinicians are encouraged to consider testing for other causes of respiratory illness, like influenza, in addition to testing for SARS-CoV-2 depending on patient age, season, or clinical setting.

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

For a visual, refer to this algorithm ‘VDH Algorithm for Evaluating a Child with COVID-19 Symptoms or Exposure.’

Test people who have had close contact with someone with COVID-19. 

VDH recommends that people who have had close contact with someone known to have COVID-19 be tested for COVID-19. This recommendation applies regardless of whether the COVID-19 case had symptoms of illness or not.

VDH defines close contact as:

  • Being within 6 feet of a person who has COVID-19 for a total of 15 minutes or more over a 24-hour period, or
  • Having direct exposure to respiratory secretions (e.g., being coughed or sneezed on, sharing a drinking glass or utensils; kissing), or
  • Providing care for a person who has COVID-19, or
  • Living with a person who has COVID-19

If there is a known exposure date, it is reasonable to test close contacts approximately one week after exposure based on the average incubation period and available evidence to date. 

If testing is not readily available, prioritize testing of symptomatic close contacts or those at increased risk for severe COVID-19

Close contacts who do not have symptoms and test negative for COVID-19 should still complete the full 14-day quarantine before it is safe to be around others. This is because it can take up to 14 days for COVID-19 symptoms to develop; if the close contact is tested too early within the 14-day period, the test might not be able to detect COVID-19 infection.

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

When personal protective equipment (PPE) and tests are in limited supply, reserve testing for selected asymptomatic people. 

The prevalence of asymptomatic and presymptomatic infection is not well understood, but these infections play a role in the transmission of SARS-CoV-2. Consider testing asymptomatic people for: 

  • Medical purposes
    • Women who are pregnant and present in labor; additional considerations here
    • Neonates born to women with confirmed or suspected COVID-19; additional considerations here.
    • People undergoing aerosol-generating procedures, within 48 hours of procedure, with limited PPE at the facility; additional considerations here.
    • People undergoing major time-sensitive surgeries, within 48 hours of procedure; additional considerations here
    • Immunocompromised people admitted to the hospital; additional considerations here
    • People undergoing immunosuppressive procedures; additional considerations here
  • Contact investigations
    • People who have had close contact with a person with lab-confirmed COVID-19, including exposed healthcare personnel; additional considerations here.
    • People who work or reside in a nursing home; additional VDH guidance here.
    • People who work or reside in a congregate setting other than a nursing home that is experiencing an outbreak; additional VDH guidance here.

Print and display ‘VDH COVID-19 Testing Algorithm’ in your healthcare facility or office. 

Report all cases to VDH.

Report all clinically suspected COVID-19 cases using VDH’s online morbidity portal at the earliest point COVID-19 is suspected. Reporting complete information, including demographics like race and ethnicity, is key to help prevent health disparities. 

VDH has developed a reporting portal 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. 

Sites that have been reporting positive POC results through the online morbidity portal will not need to do so any longer once they begin reporting through the POC Reporting 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.

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 are conducting specimen collection and either performing POC tests or sending specimens to a private or reference laboratory for testing. To find a site for your patient, visit Virginia COVID-19 Testing Sites. Each site has different policies and procedures for testing and billing.

For certain situations that meet VDH prioritization criteria, send specimens to Virginia’s public health laboratories. 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 (DCLS) courier site or shipping them via commercial courier (e.g., FedEx).

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.

Test patients using a diagnostic test for COVID-19.

Viral (RT-PCR or antigen) tests check samples from the respiratory system or saliva to determine whether COVID-19 is present. Viral tests are recommended to diagnose infection. 

The first type of viral test is a molecular-based test, such as a RT-PCR test, that detects the virus’s genetic material. 

Table 1. Molecular-based test (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 ● Current infection 

● Prompt isolation until no longer infectious by symptom-based strategy 

● If admitted to a healthcare facility, use transmission-based precautions

 ● Follow situation-specific patient management (e.g., delay major surgeries, if possible)

● Current infection 

● Prompt isolation until no longer contagious by time-based strategy

● If admitted to a healthcare facility, use transmission-based precautions

 ● Follow situation-specific patient management (e.g., delay major surgeries, if possible)

● Current infection 

● Prompt isolation until no longer contagious by time-based strategy

● If admitted to a healthcare facility, use transmission-based precautions

 ● Follow situation-specific patient management (e.g., delay major surgeries, if possible)

Negative
  • 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
  • RNA was not detected⥉
  • Close contacts who test negative must still complete 14 days of quarantine.
  • 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. 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).
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.
      • 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 90 days 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 actually 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 no active infection 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.

 

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 relatively inexpensive 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 been authorized by the FDA under an EUA 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 November 12, 2020, all rapid, point of care antigen tests have language in their EUAs stating the test is meant for use in symptomatic individuals who are suspected of having COVID-19.

Laboratory and testing professionals who conduct diagnostic or screening testing for SARS-CoV-2 with rapid 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 testing. 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, view VDH’s Antigen Testing Recommendations.

Table 2. 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 •   Current infection

•   Prompt isolation until no longer contagious by symptom-based strategy

•   Current infection

•   Prompt isolation until no longer contagious by time-based strategy

•   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 •   No antigens were detected

•   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 must still complete 14 days of quarantine.

•   Obtain COVID-19 PCR test if person develops symptoms

•   No antigens were detected

•   No additional case follow-up necessary

•   Reinforce prevention measures

#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.
      • Caveats: False positives can occur, especially in areas of low COVID-19 prevalence. Results should be interpreted in the context of disease prevalence, the device’s performance characteristics and instructions for use, and the patient’s clinical signs, symptoms, and history.
    • A negative antigen result indicates no active infection 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 a rapid 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 what your antigen test results mean and what are the next steps to take, see the VDH Antigen Testing Results and Next Steps Handout.

 

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.

    • A positive antibody result indicates that the person might have been infected with the virus at some point in the past.
      • 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 yet 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.

 

Collect and test specimens safely. 

For initial diagnostic testing for SARS-CoV-2, collect and test one of the following acceptable upper respiratory specimens (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 specimen taken with a nasopharyngeal (NP) swab as part of a COVID-19 test. The New England Journal of Medicine also has a brief video: How to Obtain a Nasopharyngeal Swab Specimen.

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

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. As a reminder, CDC recommends that all healthcare providers implement universal source control with masks for everyone entering a healthcare facility, regardless of symptoms.

Table 3.  General guidance for the preferred types of specimen collection*

Specimen Type PPE Equipment Instructions
Nasopharyngeal (NP) 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 ear to the nostril of the patient, indicating contact with the nasopharynx. Swab should reach depth equal to distance from nostrils to outer opening of the ear. 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 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 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.

*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 more information, read CDC Guidelines for Clinical Specimens.

 

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 would produce a false positive result. 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): probability a person with a positive SARS-CoV-2 test result actually has SARS-CoV-2 and was infected. Calculated by: [a/a+b]*100; PPV goes up as prevalence increases and down as prevalence decreases
  • Negative predictive value (NPV): probability a person with a negative SARS-CoV-2 test result does not actually have SARS-CoV-2 and was not infected. Calculated by: [d/c+d]*100; As 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: November 19, 2020