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For the health and safety of others, if you've been exposed to someone with COVID-19 or have COVID-19 symptoms and are waiting for a test or your results, stay home and isolate from others. Learn more about COVID-19 testing and when you should get a test below.
Your health care provider can best advise you about the need to be tested for COVID-19. Testing is encouraged if you have COVID-19 symptoms or were recently exposed to someone who tested positive for the virus.
If you're vaccinated, wait to get tested until day 5 after your last exposure to someone with COVID-19, according to the CDC. (The day of exposure is day 0.) Testing before day 5 is likely to be too soon to indicate if you have developed, or will develop, an infection. During the five-day period, stay away from other people, including those you live with. Wear a well-fitting mask at all times if you must be around other people. If, after day 5, you test negative, you should continue to wear a well-fitting mask until day 10.
Health experts caution that COVID-19 tests only tell you what your status is for that exact moment in time. For example, you could have been exposed to the virus a few hours before testing but haven’t reached the viral level that can be detected by a COVID-19 test. If you test positive, follow isolation recommendations.
View the CDC's full quarantine and isolation guidelines for vaccinated and unvaccinated people
View a list of COVID-19 symptoms you should watch for
Find a COVID-19 testing site in California near you
You can find a COVID-19 testing location near you through the state of California’s COVID-19 website.
You can view individual county testing resources as well:
UC Davis Health patients and non-patients with COVID-19 symptoms can contact a doctor through UC Davis Express Care or by contacting your primary care provider by phone or MyUCDavisHealth. A doctor can help quickly coordinate a COVID-19 test, possibly at a UC Davis Health drive-up site in Sacramento, which are available seven days a week.
Access UC Davis Express Care for patients
Access UC Davis Express Care for patients
Healthy Yolo Together, a public health project of UC Davis, also provides free saliva-based COVID-19 testing at locations in Yolo County.
Read more from UC Davis Health: More options than ever for at-home and community COVID-19 tests
You should get tested 5 days after your last close contact with someone with COVID-19. If you develop COVID-19 symptoms, get tested anytime within 10 days after exposure. If you had confirmed COVID-19 within the past 90 days (you tested positive using a viral test), then there's no need for you to get tested unless you have symptoms.
If you were exposed to someone who tested positive for COVID-19, are up-to-date with your vaccinations OR had confirmed COVID-19 in the past 90 days, and don't have COVID-19 symptoms:
If you were exposed to someone who tested positive for COVID-19 and are not up-to-date with your COVID-19 vaccinations, but are asymptomatic:
View the CDC's full quarantine and isolation guidelines
Learn how to get your COVID-19 vaccine at UC Davis Health
You could test positive for COVID-19 for weeks to months after infection. The PCR tests generally stay positive longer than the antigen tests. Positive tests do not always indicate that you can spread COVID-19 to others and may not correlate with infectiousness.
A diagnostic test, known as a molecular PCR test, uses a nasal swab and collects samples of cells and fluids from your respiratory system. It enables the identification of specific genes for the SARS-CoV-2 virus that causes COVID-19. The specimen is collected using a long nasal swab that is inserted into the passageway between the nose and the back of the throat. PCR tests, like the ones used by UC Davis Health's lab, are close to 100% accurate in diagnosing COVID-19 infection, but the disadvantage is they take a little more time for results.
Rapid antigen tests account for most of the rapid diagnostic tests. These are done with a nasal or throat swab and looks for a protein that’s part of the virus. Antigen tests are less expensive and have a generally quicker turnaround time, sometimes within 15 mins. However, they are less accurate because if a person is not near peak infection, but still contagious, the tests may come back negative. The CDC advises people who show COVID-19 symptoms but test positive with an antigen test to get a PCR test to confirm results.
An antibody test, also known as a serology test, is done with a blood sample that may identify past infection of the virus that causes COVID-19. It’s a test that looks for evidence of the body’s immune response to the virus. Antibodies are detected in the blood after an infection. However, with COVID-19, we don’t fully know what the presence of its antibodies means yet.
Learn more about the different types of COVID-19 testing
To determine which test you should take, know why you’re being tested.
If a rapid test is more available or convenient, it’s a good idea to use it. If it’s positive, you can rely on the result. Rapid antigen tests are now being used at schools for rapid screening. They are good for this purpose. Or maybe your child has been exposed at school, and after quarantining per the CDC guidelines, they need to have two negatives tests. So, the parents may want to buy a rapid antigen home kit.
But in other instances, if the rapid test is negative, particularly if you suspect infection, it’s best to get a molecular PCR test to double-check since the PCR test is more sensitive. A PCR test can be used for asymptomatic testing or to confirm a positive antigen test. It’s also used when patients have symptoms, need to be tested before a procedure, or when they are being admitted to the hospital. PCR tests are often used to make clinical decisions.
With all home-use tests on the market, whether antigen or PCR, following testing instructions is very important to ensure the quality of testing. For example, if a swab isn’t inserted deep enough into the nose, it may not collect a good sample for testing and may give a false negative.
Read more from UC Davis Health: More options than ever for at-home and community COVID-19 tests
UC Davis Health patients and non-patients with COVID-19 symptoms can contact a doctor through UC Davis Express Care or by contacting your primary care provider by phone or MyUCDavisHealth. A doctor can help quickly coordinate a COVID-19 test, possibly at a UC Davis Health drive-up site in Sacramento, which are available seven days a week.
Access UC Davis Express Care for patients
Access UC Davis Express Care for non-patients
Read more from UC Davis Health: More options than ever for at-home and community COVID-19 tests
COVID-19 tests are free at testing sites. If you’re insured, you can get a COVID-19 test from your health provider or any out-of-network provider. If you don’t have insurance, the government pays for your test.
If you test positive for COVID-19, you should contact your health care provider right away. You should also notify any people who were recently around you so they can watch for symptoms and get tested if needed.
Rapid antigen tests search for protein pieces from the virus and are known to be less sensitive than molecular PCR tests. These COVID tests perform best with people in the early stages of COVID-19 infection, when viral load is the highest.
No test is completely accurate, which means that some cases will be missed (false negatives) and some people will be told they have the virus when they don’t (false positives). Positive tests tend to be accurate, but negative tests need to be interpreted with caution, especially in a high-risk setting or when used on asymptomatic people.
Rapid antigen tests are best used as intended, where a person tests at least twice over a 36- to 48-hour period to increase the odds of detecting an infection.
View the FDA’s list of over-the-counter antigen tests that have been authorized for emergency-use authorization
Learn more about COVID rapid tests
UC Davis Health has rolled out a groundbreaking, highly accurate test that can check for both COVID-19 and flu viruses at the same time, returning results in 20 minutes. We are the first in the region and among the first in the nation to use these rapid, combined molecular tests at the point of care.
For now, the combined COVID-19 and flu tests will be limited to the emergency department or situations when speed is critical to understand a patient’s condition. Fast, accurate flu and COVID-19 results can help with management and treatment of both viruses. They can also eliminate hours or sometimes days of anxiety for patients.
Read more about the rapid test for flu and COVID-19
Learn more about COVID rapid testing
If you have serious symptoms of illness, contact your primary care provider. UC Davis Health patients can use the MyUCDavisHealth symptom tracker to evaluate whether to seek help. Telehealth video visits and Express Care are also available.
If you think you've been exposed to COVID-19, please see current testing information.
If you have a medical emergency, call 911 and notify them of your COVID-19 symptoms.
To help limit spread of COVID-19, we have policies for visits to our hospital and outpatient clinics.
UC Davis Medical Center visitor policy
Outpatient clinic policy for caregivers
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