Ask 2: Are saliva samples an accurate means of COVID-19 testing compared to nasal swabs?

Medical student Kimberly Olivares, left, takes a sample from a patient at a free COVID-19 testing site provided by United Memorial Medical Center, Sunday, June 28, 2020, at the Mexican Consulate, in Houston. Confirmed cases of the coronavirus in Texas continue to surge. On Friday, Texas Gov. Greg Abbott shut down bars again and scaled back restaurant dining as cases climbed to record levels after the state embarked on one of America's fastest reopenings. (AP Photo/David J. Phillip) (David J. Phillip, Copyright 2020 The Associated Press. All rights reserved.)

HOUSTONAt KPRC 2, we’re dedicated to keeping Houstonians informed. As part of our Ask 2 series, the newsroom will answer your questions about all things Houston.

Question: There is a group doing COVID-19 testing via saliva samples (versus nasal swab). Is this an accurate means of testing as compared to nasal swabs?

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Answer: Yes, in fact, local sinus and allergy clinic BreatheMD, says saliva-based testing is safer and more accurate than the nasal swab.

The Upper Kirby medical facility, which has tested over 1,200 patients for COVID-19 using saliva samples, also said that the lab they used MicrogenDX has shown the viral load in saliva to be 10 times greater than that found in respiratory secretions.

Saliva tests allow patients to spit into a tube or cup rather than getting their nose or throat swabbed, making it easier and more comfortable for some, as well as safer for medical personnel who can be further away during the sample collection, according to the U.S. Food and Drug Administration.

Both saliva and nasal swab collection methods are U.S. Food and Drug Administration-approved molecular tests, also known as rRT-PCR tests, that detect the genetic material in the virus.

However, the FDA does state that neither test is 100% accurate all of the time due to certain factors that may affect the tests’ accuracy including:

  • A person may have the virus but the swab might not collect it from their nose or throat
  • The swab or mucus sample may be accidentally contaminated by the virus during collection or analysis
  • The nasal or throat swab may not be kept at the correct temperature before it can be analyzed
  • The chemicals used to extract the virus’s genetic material and make copies of the virus DNA may not work correctly

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