Testing for infection with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, can inform individual patient care and decision-making for parents and families. In addition, population-level testing helps determine what interventions may need to be put in place to control the spread of disease within a community. This guidance is intended to assist pediatricians in understanding indications for SARS-CoV-2 testing as well as test selection and interpretation. The document also provides algorithms for common testing scenarios and information about practical considerations for in-office testing for SARS-CoV-2. No guidance can cover all clinical scenarios, and information regarding SARS-CoV-2/COVID-19 is evolving rapidly. Links to guidelines and research from CDC and other organizations are provided for additional information to help guide decision making.

Testing Indications

Patients with symptoms consistent with COVID-19

Symptoms Consistent with COVID-19 (Any of the following) 

  • Fever or chills 
  • Cough 
  • Congestion or runny nose 
  • Loss of taste or smell 
  • Shortness of breath or difficulty breathing 
  • Body aches 
  • Fatigue or headache 
  • Sore throat 
  • Nausea, vomiting, or diarrhea 
  • Testing for SARS-CoV-2 infection should be guided by clinician judgment in accordance with the prevalence of COVID-19 in a given community.
  • Given the occurrence of breakthrough SARS-CoV-2 infections in vaccinated individuals, the vaccine status of the patient should not guide decisions about testing in the setting of compatible symptoms.
  • Children who have had laboratory-confirmed SARS-CoV-2 infections in the prior 3 months may continue to have positive test results even in the absence of current infection. In particular, small amounts of viral genetic material may remain detectible for several months after infection. Nucleic acid amplification tests (NAATs – see Test Selection and Interpretation below) including polymerase chain reaction (PCR) may remain positive during that time despite clinical recovery and lack of contagiousness. Decisions about testing symptomatic children with prior confirmed infections in the past 3 months should take into account the possibility of false-positive results. In a child with known exposure and compatible symptoms, there may be situations in which it is reasonable to retest within the 3-month window.
  • The decision to test does not differ by the age of the child, although some symptoms such as body aches, shortness of breath, and loss of taste/smell are more prevalent in young adults than in school-aged children.
  • It is reasonable to decide not to test for SARS-CoV-2 infection in the context of other illnesses that lack shared symptoms (eg, cellulitis, urinary tract infection, etc) if no symptoms compatible with COVID-19 are present.
  • Decisions regarding testing for other pathogens should be informed by local epidemiology including current levels of community transmission. Diagnosis of some other infections that share symptoms with SARS-CoV-2 (eg, influenza) may be clinically actionable, and coinfections may occur. Children with influenza documented by testing may be treated with an influenza antiviral, with more rapid resolution of symptoms possible, allowing for earlier return to school, per AAP policy. Clinicians should consider local seasonal influenza activity when deciding whether to test patients for influenza. Tests for many common causes of upper and lower respiratory tract symptoms, such as rhinovirus, are not routinely available.
  • See AAP Newborn Guidance for additional information about testing newborn infants.

Patients who have close contact with individuals with confirmed or probable SARS-CoV-2 infection

Key Definitions

Close contact: a distance of less than 6 feet for a cumulative total of at least 15 minutes over a 24-hour period from a person with laboratory-confirmed or probable SARS-CoV-2 infection starting from 2 days before illness onset (or, for asymptomatic patients, 2 days prior to test specimen collection) until the time the patient is isolated. The period that one is considered a close contact is for 14 days from last contact with the index case. Wearing a mask or cloth covering is presently not considered sufficient to alleviate the risk of transmission if close contact conditions are met, regardless of vaccination status.

Fully vaccinated: In general, children will be defined as fully vaccinated if they are ≥14 days past the final dose of their primary COVID-19 vaccine series (second dose for an mRNA vaccine; first dose for the Johnson & Johnson adenovirus vector vaccine). If that condition is not met, the individual should be considered unvaccinated or “not fully vaccinated.”

 

  • Patients who meet the definition of close contact above should be tested for SARS-CoV-2 infection. Testing for active SARS-CoV-2 infection may be considered for exposures of shorter duration or greater distance, or intensity of exposure, on a case-by-case basis.
  • If the patient (the one who has been in close contact with a confirmed/probable case) has symptoms consistent with COVID-19 (See above), testing should be performed without delay and without regard to vaccination status. Testing these patients in a timely fashion is important especially if participating in school, sports, or work so that local groups can begin contact tracing, outlining school/work closures, and notifying families to begin home quarantines until test results are received.
  • If the patient is asymptomatic and not fully vaccinated, testing should be performed without delay once it is determined he or she is a close contact. If the test result is negative, it should be repeated at 5 to 7 days after the last exposure (or immediately if symptoms develop).
  • If the patient is asymptomatic and fully vaccinated, testing should be delayed for 5 to 7 days after the most recent contact with the confirmed/probable case. If symptoms develop during that period, the patient should be tested immediately. The probability of a false-negative result decreases substantially over the first 5 days after exposure. Because symptoms develop 2 to 14 days following exposure and most commonly between 5 and 6 days, further testing after an appropriately timed negative test result should be guided by symptoms and the presence of ongoing exposures.
  • In general, asymptomatic children who have had laboratory-confirmed SARS-CoV-2 infections in the prior 3 months may be exempted from testing after close contact exposures.
  • Testing for SARS-CoV-2 infection is not necessary if there is exposure to a close contact of an individual with confirmed/probable SARS-CoV-2 infection and not the infected person themselves, unless the close contact is also a confirmed/probable case.

Screening testing in asymptomatic individuals without known SARS-CoV-2 exposures

  • Screening testing of asymptomatic individuals without known SARS-CoV-2 exposures may be required in a variety of settings, including but not limited to school or camp attendance, extracurricular activities, employment, air travel, or health care settings (such as admission for reasons unrelated to SARS-CoV-2 infection/COVID-19).
  • Screening testing is generally carried out under the guidance of local public health authorities, school districts, or other local organizations, consistent with state and federal laws. It is important for pediatricians to be aware of local testing practices and requirements and to work in concert with the relevant authorities.
  • Unlike testing of symptomatic individuals, the vaccination status of the individual may affect decisions about the need for screening.

Specific situations in which screening testing may be used:

  • School/Camp Attendance
    • The CDC and AAP strongly support efforts to provide safe, in-person instruction in K-12 schools. Screening (ie, testing of groups of asymptomatic individuals without known SARS-CoV-2 exposure) may be useful for early identification and isolation of SARS-CoV-2 cases, identification of additional potentially exposed individuals through contact tracing, and detection of clusters of cases.
    • In some cases, including some examples of school screening strategies provided by CDC, fully vaccinated students may be exempted from screening testing protocols. School districts and local health authorities may elect to include fully vaccinated students in screening programs.
    • In general, children who have had laboratory-confirmed SARS-CoV-2 infections in the prior 3 months may be exempted from screening protocols. School districts and local health authorities may elect to include students with confirmed SARS-CoV-2 in the past 3 months in screening programs.
    • Screening can be offered to students who are not fully vaccinated against SARS-CoV-2 at times when local community transmission is at moderate, substantial, or high levels (as defined by the CDC) as part of a layered approach to mitigation in schools.
    • Because of the incubation period of SARS-CoV-2 infection, screening programs should be offered at least once per week. Many schools opt to test a random subset of students (approximately 10%) weekly.
    • Some testing strategies for school screening testing are discussed below. Decisions about testing strategies should take into account local epidemiology, testing characteristics, turnaround time, and cost. More information is available from CDC.
  • Extracurricular Activities and Workplace Screening
    • Preparticipation screening of children may be performed prior to higher-risk extracurricular activities (eg, intermediate- or high-risk sports, or high-risk extracurriculars such as those that involve increased exhalation such as singing, shouting, band, or other exercise), particularly for activities conducted indoors. Specific CDC recommendations regarding such screening are available.
    • Screening in these situations depends on the specific activities, physical spacing, and the relative rates of disease in a community.
    • Adolescents who are employed may be subject to screening testing as a condition of employment. Such policies are instituted by employers, subject to local public health guidance and applicable laws.
  • Air Travel (detailed information is available at the CDC website)
    • There are currently no requirements for testing prior to or following domestic travel within the United States and its territories.
    • International travel poses additional risks and even fully vaccinated travelers are at increased risk for getting and possibly spreading new COVID-19 variants. CDC recommends delaying international travel until individuals are fully vaccinated.
    • The United States currently requires SARS-CoV-2 testing for all incoming international travelers regardless of vaccination status.
    • Outbound international travelers who are unvaccinated are required to have SARS-CoV-2 testing within 3 days of departure.
    • All outbound international travelers regardless of vaccination status or recent prior infection should check entry requirements at their destinations, which may differ from those of the United States.
    • In general, children who have had laboratory-confirmed SARS-CoV-2 infections in the prior 3 months may be exempted from international travel testing protocols established by the United States, but these protocols may vary by destination, as noted above.
  • Health Care Settings
    • Many hospitals recommend that children receive testing for active SARS-CoV-2 infection prior to outpatient procedures such as elective surgery and for all children admitted to a hospital for any reason. These decisions should be made on the basis of local recommendations and institutional policies.
    • Parents or other caregivers of children may be subject to public health requirements and hospital-based or other health care-based screening policies as well.

Test Selection and Interpretation

Key Definitions

Viral Tests: tests that detect the presence of SARS-CoV-2 nucleic acid or proteins. This category includes both NAAT and antigen tests.

Nucleic Acid Amplification Tests (NAATs) include polymerase chain reaction (PCR) tests as well as strategies for isothermal amplification of nucleic acid, such as loop-mediated isothermal amplification (LAMP) and nicking enzyme amplification reaction (NEAR). NAATs are generally performed on respiratory tract samples, most often nasal or nasopharyngeal swab specimens, and more recently, saliva samples. A PCR test that has received FDA authorization or approval is the “gold standard” for testing an individual child for acute SARS-CoV-2 infection.

Antigen Tests are generally performed on nasal or oral swab specimens. Antigen tests generally have lower sensitivity than molecular tests, particularly in later stages of COVID-19. Some antigen tests have rapid turnaround at the point of care, making them useful for specific situations, including screening testing and at-home use, particularly for those who are symptomatic.


Nonviral Tests: tests that detect immune responses to SARS-CoV-2 infection or vaccination. This category includes antibody (serologic) tests.

Antibody (Serologic) Tests can provide evidence of previous infection with SARS-CoV-2 but are not useful for the diagnosis of acute infection. A positive antibody test result does not prove that a patient has protection against SARS-CoV-2, and results of these tests should not be used to guide decisions about the need for vaccination or to group people in classrooms or other facilities. Individuals with positive antibody tests should continue to adhere to guidelines about masking, physical distancing, and other preventive measures. 


Test selection

  • Decisions about testing platforms may take into account local epidemiology and test characteristics such as sensitivity, specificity, and positive/negative predictive values.
  • Practical considerations such as test availability, turnaround time, and cost may be important factors as well.
  • There are positive and negative aspects to all available SARS-CoV-2 testing platforms. Some of these are reviewed in Table 1 below:


Table 1. Positive and Negative Aspects of SARS-CoV-2 Testing Platforms

positive and negative aspects covid testing.jpg

Test interpretation

Key Definitions

Sensitivity: Ability of the test to correctly identify those with SARS-CoV-2 infection (true positive rate).

Specificity: Ability of the test to correctly identify those without SARS-CoV-2 infection (true negative rate).

Pretest Probability: Likelihood of a particular individual patient having SARS-CoV-2 infection based on community prevalence, exposure, symptoms, and other factors.

Positive Predictive Value (PPV): Probability that people who test positive are truly positive (ie, they have SARS-CoV-2 infection).

Negative Predictive Value (NPV): Probability that people who test negative are truly negative (ie, they do not have SARS-CoV-2 infection).

 

  • Interpretation of SARS-CoV-2 test results depends on the sensitivity and specificity of the chosen test as well as community prevalence and the reason the test was performed (symptomatic vs exposure vs epidemiologic studies).
  • Sensitivity and specificity are test characteristics that do not vary based on community prevalence. Available data for specific testing platforms may vary and pediatric data may not be available, particularly for newer tests made available under emergency use authorization.
  • Sensitivity and specificity alone are not enough to determine a test’s reliability. Pretest probability must be combined with sensitivity and specificity to give the positive predictive value (PPV) and negative predictive value (NPV) of the test.
  • Note that the context in which the test was performed, the result of a test, and the clinician and family’s risk tolerance in a given situation determines whether a particular test’s result is “good enough.”
  • Receipt of SARS-CoV-2 vaccine does not result in positive NAAT or antigen test results. Antibody (serology) tests that detect responses to the spike (not nucleocapsid) protein may become positive following vaccination. Antibody testing is not recommended to determine immunity to COVID-19 following vaccination or to assess the need for vaccination.
  • Interpretation of point-of-care or at-home testing performed by schools, workplaces, parents, or others: There are several home tests with Emergency Use Authorization, with both molecular and antigen options available. These tests have become less costly and more readily available as schools, employers, and public gatherings search for more convenient ways to exclude COVID infection for asymptomatic individuals or those with mild/vague symptoms. Pediatricians are challenged to evaluate these test results because of the inability to verify the adequacy of the sample collection or whether the testing procedure was performed correctly. Generally, because of the high specificity of these tests, any positive result should result in home quarantine. As these tests become more affordable and readily available, the absolute number of false positives will increase even if the relative rate of false positives remains very low. If the pretest probability is high (eg, high prevalence of disease in community, close-contact exposure, or symptoms), a NAAT (PCR) confirmation is generally not necessary after a positive at-home test result, and the patient should quarantine per routine and notify other potential contacts. If the pretest probability is low (eg, low community prevalence, no symptoms or exposures), a NAAT such as PCR should be considered, although a negative PCR test result does not eliminate the need to quarantine. Specific situations will be discussed in the Testing Algorithms section below.

Testing Algorithms

The algorithms below are intended to provide guidance for common clinical situations. Please see CDC testing guidance including the Interim Guidance for the Use of Antigen Testing and the draft Antigen Testing Algorithm for further details.

Table 2 provides an interpretation to the color-coded outcomes in testing of symptomatic and asymptomatic children as noted in the following algorithms. These algorithms assign patients to one of three categories based on a combination of pretest probability (including both clinical presentation and exposures) and testing results:

COVIDtesting_Table2.png

In each algorithm, a pathway is provided depending on whether the initial testing is performed with a PCR test or an antigen test. Non-PCR NAATs have not been included because of limited availability and limited performance data in children. Until more pediatric data are available, we suggest considering results of non-PCR NAATs such as LAMP and NEAR assays as comparable to antigen testing rather than PCR. This guidance may change in the future as more data become available.

COVIDtesting_AlgorithmA.png

  • Patients who have symptoms consistent with COVID-19 should be tested without delay. Given the ongoing spread of SARS-CoV-2 throughout the United States, a positive test (PCR or antigen) in a symptomatic patient should be taken as evidence of SARS-CoV-2 infection.
  • A symptomatic patient with a negative PCR test (done either as an initial test or as follow-up to a negative antigen test) who has a known close contact exposure to an individual with confirmed or probable SARS-CoV-2 infection in the past 14 days falls into the “no current evidence of SARS-CoV-2” category and requires quarantine. These patients may have symptoms from another viral infection while still potentially in the incubation period with SARS-CoV-2 and therefore require continued quarantine.
  • A symptomatic patient with a negative PCR test (done either as an initial test or as follow-up to a negative antigen test) but without a known exposure to an individual with confirmed or probable SARS-CoV-2 infection in the past 14 days can be considered “not infected with SARS-CoV-2” but should still isolate until symptom resolution.

COVIDtesting_AlgorithmB.png

  • Asymptomatic patients with close contact exposure to an individual with confirmed or probable SARS-CoV-2 infection in the past 14 days should be tested for SARS-CoV-2 infection.
    • If the patient is asymptomatic and not fully vaccinated, testing should be performed without delay once it is determined he or she is a close contact. If the test result is negative, it should be repeated at 5 to 7 days after the last exposure (or immediately if symptoms develop).
    • If the patient is asymptomatic and fully vaccinated, testing should be delayed for 5 to 7 days after the most recent contact with the confirmed/probable case. If symptoms develop during that period, the patient should be tested immediately.
  • Asymptomatic children who are not fully vaccinated against SARS-CoV-2 and who have negative testing require quarantine.
  • If an asymptomatic child who is fully vaccinated against SARS-CoV-2 has close contact with an individual with confirmed SARS-CoV-2 infection, the child does not need to quarantine per CDC guidance. However, the child should wear a mask in all public indoor settings for 14 days or until a negative test result is received. Similar guidance applies if the exposed person has had laboratory-confirmed SARS-CoV-2 infection in the past three months.
  • New approaches to school screening test results have been developed, including the “test to stay” strategy, under which close contacts of confirmed cases can shorten or eliminate the quarantine period by utilizing frequent testing. This approach is not currently endorsed by the CDC or AAP, although as more data become available, it may become more widespread.

COVIDtesting_AlgorithmC.png

  • Screening testing algorithms apply to children who do not have symptoms consistent with COVID-19 and who do not have a known close contact exposure to an individual with confirmed or probable SARS-CoV-2 infection in the past 14 days.
  • Many schools are using new testing platforms to balance test accuracy with cost and logistical barriers to use. For example, pooled PCR testing followed by individual testing of samples from positive pools can decrease cost, although turnaround time may be increased.

Practical Considerations for In-Office Testing

  • Decisions about offering in-office SARS-CoV-2 testing may involve many factors including:
    • Equipment and supply availability and cost
    • Access to specific testing platforms
    • Staff training and need for CLIA certification for some platforms
    • Patient/family convenience and access to other sites for testing
    • Reporting and other regulatory requirements
    • Potential for increased wait times if families wait for results
  • PPE requirements: PPE is often necessary for testing but depends on the test being used (saliva vs nasal vs nasopharyngeal specimens), the developmental age of the patient, and the potential to aerosolize during the testing process. At a minimum, the use of gloves, face mask, and eye protection is necessary for all specimen handling and collection. When collecting samples using nasopharyngeal swab; for patients for whom crying, gagging, or coughing is likely; or for patients who are otherwise deemed as higher risk, such as high suspicion of SARS-CoV-2 infection based on household contacts, the addition of gowns and N95 masks is encouraged. Gowns and gloves should be changed between each collection, per AAP interim guidance on PPE. For tests that can be administered as self-swabs, no additional PPE is required (although staff members must directly observe to ensure adequate sample collection).
  • Reporting test results to local public health authorities: At a minimum, pediatricians should follow state and local guidelines regarding reporting test results to public health officials to allow for contact tracing and quarantine, if appropriate. Local and state health department guidelines on reporting persons under investigation (PUIs) may vary; however, the CDC is not monitoring PUIs at this time. Although many reference laboratories will report testing directly to local health departments, point-of-care testing requires daily submission of positive, and sometimes negative, results depending on state requirements. This is relevant to pediatricians who elect to perform in-office testing.

 

Interim Guidance Disclaimer: The COVID-19 clinical interim guidance provided here has been updated based on current evidence and information available at the time of publishing. Guidance will be regularly reviewed with regards to the evolving nature of the pandemic and emerging evidence. All interim guidance will be presumed to expire on December 31, 2021 unless otherwise specified.

Last Updated

11/15/2021

Source

American Academy of Pediatrics