Saliva Test for COVID: Your Questions Answered

Saliva Test for COVID: Your Questions Answered

You now have a more comfortable and affordable COVID test in the Philippines. A new saliva RT-PCR test is available for anyone who can spit on demand, including those who are asymptomatic. It provides results quickly, with only a funnel and tube needed for collection.

Unlike traditional “swab” tests, which involve inserting a long swab into the back of your nasal cavity, the saliva RT-PCR test only requires a small saliva sample. You then drop it in a tube and hand it over to your testing provider for lab analysis.  

In this article, we’ll cover some of the finer points of the saliva COVID test, such as how it compares with a nasal RT-PCR, the test’s accuracy, and where you can get tested in the Philippines.

What’s the difference between the nasal PCR and the Saliva PCR test?

The nasal PCR test and the Saliva RT-PCR test are very similar in the way they work. They both detect COVID-19 virus RNA and must be analyzed in a certified clinical laboratory. However, the Saliva RT-PCR is processed in fewer steps and requires simple materials for collection. This means faster turnaround times and a reduced saliva test price for the patient.

Compared to a nasal swab test, many people find saliva collection more comfortable. It is non-invasive and requires only that you spit into a container.  

How and When is it Performed?

Collection methods may differ slightly between saliva test kits. But the general process involves spitting into a funnel that connects to a specimen tube. Afterward, you return the tube to the lab for analysis.

As far as timing, the CDC applies the same timeframe as other types of COVID tests. If you’re symptomatic, test immediately. If you’re asymptomatic, the ideal day to test is day 5 after exposure.

Guidelines for Collecting a Good Saliva Specimen

The laboratory needs the liquid part of your saliva to perform a successful test. Your saliva needs to be clear and free of mucus and debris. Please follow these guidelines before the saliva covid test to get the most accurate results:

At least 30 minutes before the test:

  • Do not drink any liquid.
  • Do not eat anything.
  • Do not brush your teeth.
  • Do not vape or use tobacco.
  • Make sure your hands are also free of contamination by washing for 20 seconds before collection.

How quickly will I get my saliva test results?

This varies widely between laboratories. Generally, it takes less time to process than a nasal swab PCR, since there are fewer steps in the lab processing. In the Philippines, the Red Cross saliva test offers results in a few hours, depending on demand. Home service testing generally has a 24-48 hour turnaround time.

Is the saliva PCR test as accurate as a nasal swab test?

Early data suggests the saliva PCR test is almost as accurate as the nasal swab PCR test. In a meta-analysis of 16 studies, researchers found only a 1.6% decrease in the sensitivity of saliva PCR tests compared to nasal swab PCR tests. Sensitivity refers to a test's ability to detect positive cases. When a saliva test is used serially (once every three days), the sensitivity rises to 98 percent. That’s on par with the nasal swab RT-PCR test.

Saliva PCR testing may be more accurate for early detection. Research at the University of Illinois suggests that testing saliva is more effective than swabs in detecting COVID at the early stages of infection — when viral loads tend to be lower.

However, COVID-19 is a rapidly evolving virus. More data is needed before drawing conclusions about whether the collection method leads to significant differences in test performance. The bottom line is that both saliva and nasal PCR tests deliver reliable results.

Benefits of a Saliva RT-PCR

Recently, there has been a push towards using saliva PCR testing as the primary method for COVID-19 diagnosis due to its faster turnaround times, lower cost, and accessibility. When choosing a test, consider the following benefits:

  • The saliva COVID test may be more accurate for early detection.
  • A saliva test is less invasive, which translates to less discomfort.  
  • Saliva COVID test components are readily available vs. nasal swab tests which can be in short supply.
  • Saliva tests are an effective and affordable method of community COVID surveillance.
  • The saliva COVID test reduces the risk of medical staff getting infected.
  • There is no RNA-extraction step at the lab. This generally means faster processing times and a cheaper price.  

Disadvantages of a Saliva Test

Every COVID test has its limitations and the saliva PCR test is not optimal for every person. Before testing, consider the following disadvantages::

  • In comparison to the nasal airways, the mouth is a more unregulated environment. What you eat or drink beforehand can impact the test.
  • When people are unwell and dehydrated, saliva can be difficult to produce.
  • It can take more than fifteen minutes to collect an adequate sample.
  • The saliva PCR test cannot be used for travelers leaving the Philippines, per the IATF.

Places To Get Saliva PCR Test in the Philippines

The Philippines market has been flooded by unreliable saliva antigen tests. These tests are not approved by the Philippines DOH. Saliva specimens are only approved for nucleic amplification-based tests, such as the PCR. It’s important to find a reputable test provider and ensure you take the saliva PCR test. Here are the laboratories in the Philippines that perform the test:

  • Singapore Diagnostics, a partner of Zennya Health, offers a saliva RT-PCR
  • The Philippines Red Cross offers a reliable saliva test

Which Type of PCR Test is Best?

Different tests have different advantages and limitations. Which PCR test is best for you will depend on your circumstances and purpose for testing. If you experience pain during the swab collection or need a more affordable test, the saliva PCR test is a better option. However, if you have difficulty with a dry mouth or are dehydrated by illness, you may wish to avoid a saliva test. If you want to explore all your test options in more detail, you can read our blog on COVID test types here.