​Related Materials: Antigen Tests Fact Sheet (PDF) | Antigen, PCR, and Serology Test Fact Sheet (PDF) | All Guidance

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What's new in this revision compared to May 1, 2020 Testing Guidance?

COVID-19 testing in California has rapidly expanded over the past three months and we have learned much about COVID-19 and which populations and communities it impacts disproportionately.

Consequently, CDPH recommends first prioritizing testing of hospitalized individuals with signs or symptoms of COVID-19 infection followed by testing of other symptomatic individuals and higher risk asymptomatic individuals and then other asymptomatic individuals when certain conditions exist. This guidance should be used for prioritization of patient populations as well as for the purposes of guiding laboratories in managing specimen processing.

Testing Discrimination and Inappropriate Workplace Testing

As modifications are made to public health directives and more sectors of the economy open with adaptations, it is important that employers do not use testing to impermissibly discriminate against employees who have previously tested positive for COVID-19 (such as by preventing them from resuming work after they can do so in a manner consistent with public health and safety).  This does not mean an employer must allow an employee who currently has COVID-19 to return to work before the employee's infection is resolved. Further, because PCR tests can remain positive long after an individual is no longer infectious, proof of a negative test should not be required prior to returning to the workplace after documented COVID infection.  Rather, symptom- or protocol-based criteria should be used in determining when an employee is safe to return to the workplace.

Types of Tests

Diagnostic Tests

Assesses the presence of the virus at a given point in time. A negative means only that an individual was negative at the time the test.

• Polymerase Chain Reaction (PCR) Tests and Nucleic Acid Amplification Testing:  Detects the RNA genetic material in the COVID-19 virus and are often collected via nasal pharyngeal, mid turbinate, nasal, oral or throat swab or saliva collection. 
• Antigen Tests: Not currently widely utilized. Detects the presence of COVID-19 specific protein particles and is collected via a respiratory sample. 

Note: No test is perfect. There is a false negative rate and false positive rate that varies depending on the test and the collection modality
Non- Diagnostic Tests

• Serology (Antibody) Tests: Detect antibodies in the blood indicating possible prior exposure to COVID-19, which may develop 6-14 days after infection. Please see CDPH guidance on Serology Tests for further information.
  
• Note: Commercially available antibody tests have variable performance—see FDA EUA Authorized Serology Test Performance Website.
  

Reminder - These are statewide guidelines. Local jurisdictions may modify these guidelines to account for local conditions or patterns of transmission.