Coronavirus Disease 2019

Currently FDA-authorized viral tests for SARS-CoV-2 (NAATs or antigen) can be used for both diagnostic and screening* purposes. When choosing the type of test to use and when interpreting test results, it is important to consider the purpose of the testing (diagnostic or screening), the test performance characteristics (sensitivity and specificity), and the pre-test probability of infection. For a detailed discussion of COVID-19 test types, their use, and interpretation, see the COVID-19 Testing page.

*Regardless of FDA authorization, for the duration of the public health emergency, CMS has indicated all SARS-CoV-2 diagnostic tests can be used on asymptomatic people. Health plans are required to pay for COVID-19 testing for their enrollees whether they are symptomatic or asymptomatic.

Diagnostic testing

The goals of diagnostic testing are to identify persons actively infected with SARS-CoV-2 virus (based on symptoms or exposure) to help guide clinical and infection control decisions. 

Diagnostic testing is indicated when infection is suspected, such as when the person:

• Has signs or symptoms of COVID-19
  Individuals who have symptoms consistent with acute COVID-19 should be tested for SARS-CoV-2 infection regardless of vaccination status or recent history of previous infection.

• Is a close contact to a confirmed case, regardless of vaccination status
  Testing is not recommended for asymptomatic close contacts who have recovered from laboratory-confirmed COVID-19 within the past 3 months (90 days).

• Is part of an outbreak investigation and response and/or case investigation
  Testing is recommended regardless of vaccination status. Investigations may include testing of asymptomatic persons with recent history of previous infection as directed by Public Health.

Nucleic acid amplification tests (NAATs) or antigen tests can be used for diagnostic testing. Negative results from less sensitive tests (e.g., antigen tests, some NAATs), should be considered presumptive and confirmation with a standard laboratory-based NAAT test (e.g., RT-PCR) is recommended if important for clinical management or infection control decisions.

Screening testing

Screening testing is intended to identify people with COVID-19 who have no signs or symptoms of COVID-19 and no known or suspected exposure to SARS-CoV-2. This is different from surveillance testing, which is intended to characterize the incidence and prevalence of disease and is performed on de-identified specimens, and thus, results are not linked to individual people.

The rationale for screening testing is to identify persons with pre-symptomatic or asymptomatic SARS-CoV-2 infection in order to prevent additional spread of the virus within specific settings. With the presence of the very infectious Delta variant in the context of highly effective COVID-19 vaccines, there are many new and updated screening requirements.

Requirements and Recommendations

Screening testing is required*:

• Workers who are not fully vaccinated in many settings including but not limited to healthcare, high-risk congregate settings (i.e., homeless shelters, correctional facilities, and detention centers), and K-12 schools. The frequency of testing depends on the setting.
• Fully vaccinated nursing facility staff as required by California Department of Public Health. Fully vaccinated staff must continue to be included in routine screening if the facility’s weekly vaccination coverage of staff and residents is below 70%. See Guidelines for Preventing and Managing COVID-19 in SNFs for more information. 
• Youth sports athletes and staff who are not fully vaccinated in moderate- and high-risk sports organized by youth sports leagues, including school sports teams. For children under 12 years of age playing outdoor moderate- and high-risk sports in organized youth sports leagues, weekly screening testing is recommended but not required. See Protocol for Organized Youth Sports.
• International travelers, regardless of vaccination status, prior to boarding a flight bound for the United States, (screening is not required for persons with proof of recovery from laboratory confirmed COVID-19 in the past 90 days).
• Visitors who are not fully vaccinated prior to entry into certain settings, including but not limited to indoor mega-events, indoors at skilled nursing facilities, intermediate care facilities, and juvenile detention facilities, indoors and outdoors at adult correctional and detention centers, and as required by certain businesses and venues.

*This list is not inclusive of all required screening testing. There are many additional settings or facilities that have their own screening testing requirements.

Screening testing is recommended:

• For persons who are not fully vaccinated in the following settings
  • Children under 12 years of age playing outdoor moderate- and high-risk sports in organized youth sports leagues, including school sports teams.
  • Prior to entry to outdoor mega-events.
• In schools
• Routine screening testing of staff and students that are not fully vaccinated is recommended as an important part of identifying cases early in the school setting so that measures can be taken to prevent further transmission given the low vaccination rate in children.
• When community transmission rates are high, surveillance testing that includes fully vaccinated staff and students in schools is appropriate if testing capacity allows.
• Before and after travel for the following persons
  
  • People who are not fully vaccinated, testing is recommended 1-3 days prior to and 3-5 days after domestic travel.
  • 3-5 days after international travel, regardless of vaccination status.

Note: organizations conducting screening testing should have a mechanism to confirm positive results in asymptomatic persons with no known exposure when the probability of infection is low. See interpretation of NAAT and antigen test sections for more information.

Screening testing is not recommended for:

• Fully vaccinated persons unless they fall into one of the categories listed above
  To date, all published literature indicate that currently authorized vaccines are highly effective at preventing serious illness and death due to COVID-19 infection and are effective at preventing most transmission. Fully vaccinated people with no COVID-19-like symptoms and no known exposure do not need to be tested for SARS-CoV-2 infection unless they fall into one of categories listed above.
• Persons who have recovered from laboratory confirmed COVID-19 within the past 90 days and are asymptomatic
  Recently infected persons are known to shed virus for up to 90 days after recovery and reinfection is unlikely to occur during this period. To avoid false positives due to detection of non-infectious viral particles, provided they remain asymptomatic, they should not be part of screening programs until at least 90 days after the onset of initial illness (or after the date of first positive viral test if they never had symptoms).

All healthcare providers and systems should be able to provide their patients with timely access to SARS-CoV-2 diagnostic testing when indicated. See Health Officer Order: Access to Diagnostic Testing Through Healthcare Facilities for more information. Organizations that need assistance to identify a suitable laboratory provider are encouraged to view the resources in the laboratories section below.

Federal law requires all plans to provide coverage of COVID-19 testing

• Federal guidance: FAQs About Families First Coronavirus Response Act and Coronavirus Aid, Relief, and Economic Security Act Implementation (February 26, 2021).

Zero Cost Sharing

• All commercial and Medi-Cal health plans in California must provide COVID-19 testing and visits with zero cost sharing. Health plans must cover the testing whether the person is symptomatic or asymptomatic and regardless of whether the person has had recent known or suspected exposure to COVID-19. See Department of Managed HealthCare All Plan Letter (7-26-21).

New State and LA County Health Officer Orders require vaccinations or regular (weekly or biweekly COVID-19 testing) for unvaccinated employees in various settings, including health care settings and schools. These require employers and facilities to test and monitor their workforce members. This document details options for employers to meet these requirements.