covid-19 testing

COVID-19 Testing

Hot Off the Press – COVID-19 Testing

 

CDC updates as of April 18, 2020:
https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html

Who should be tested?

– The CDC clinical criteria for considering testing for COVID-19 have been developed based on what is
known about COVID-19 and are subject to change as additional information becomes available.

– Please click on the link below to see the priority for testing based upon availability of test kits.
https://www.cdc.gov/coronavirus/2019-ncov/downloads/priority-testing-patients.pdf

– Testing for other more common pathogens should be conducted whenever possible before Co-VID19
testing is requested. Flu and other respiratory pathogens are still in circulation in Houston.

What test should be used?

RT- PCR test by deep nasopharyngeal swab
– This is the gold standard for detecting the virus and confirming diagnosis of CoVID 19 infection.
– Test is performed by “moderate to high complexity labs” such as Quest and Hospital Laboratories.
– On a patient who has been ill for more than 24 hours, if the specimen is collected properly by ddep
nasal swab by trained medical personnel, the test is 97-99% sensitive and 99% specific.
– We do not run this test on site. We collect the swab, place in viral transport media and send to Quest.
– Turn-around time for Quest is generally 3-7 days, but we have seen it take up to 11 days.
– Turn-around time for patients tested in hospital is same day. We are not allowed to submit specimens
to hospitals for testing.
Abbott ID Now CoVID 19 Testing – approved under the Emergency Use Authorization
– This is a new rapid PCR testing for one gene of the Covid 19 virus that is performed with nasal swab.
– Results are rapid – less than 15 minutes.
– Higher rate of false negatives than the formal PCR test which tests for more genes and uses deep
nasopharyngeal swab collected by trained medical personnel.
– This is available in moderate complexity labs such as pharmacies and direct to consumer available labs.
– If you test negative through this method, but you have fever and respiratory symptoms, it is still
possible that you are infected with Covid 19.
Serology Testing – Beware of companies claiming accurate serology testing by finger-poke samples.
– Blood is drawn and tested for antibodies against CoVID 19 in high complexity labs.
– IgM antibodies are usually elevated within 2 weeks of infection.
– IgG antibodies indicated a remote infection and some degree of immunity at least temporarily.
– Serology testing is still being evaluated and changes are happening day-by-day.

Please follow information based upon the CDC and FDA links in regard to this rapidly evolving form of testing:

https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html
https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-serological-tests