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Miriam Quiambao Tests Positive for COVID Despite Initial Negative Antigen Result

Expertly reviewed by Dexter Macalintal, MD · Internal or General Medicine

Written by Lorraine Bunag, R.N. · Updated Mar 16, 2022

Miriam Quiambao Tests Positive for COVID Despite Initial Negative Antigen Result

Beauty Queen Miriam Quiambao-Roberto recently shared that she’s COVID-19 positive despite having negative antigen test results. More on Miriam’s experience and the topic, RT PCR vs antigen test, in this article.  

Miriam’s Story

Reports say it was the Robertos’ helper who first tested positive for COVID-19. Thankfully, the helper received her negative test result after a week of isolation. But their ordeal with SARS-CoV-2 didn’t end there. 

A day or two after they received the Janssen vaccine, Miriam developed symptoms. The family thought it was just the side effect of the shot. Then, a day or two after Miriam developed symptoms, her husband, Ardy Roberto, started having symptoms as well, although he thought it was just the flu. 

Miriam’s antigen test was negative, but a few days later, they learned that she really has COVID-19. 

rt pcr vs antigen test
Image: Instagram/@ardyroberto

RT PCR vs Antigen Test: What’s the Difference?

Many of us already understand that the RT PCR or Reverse Transcription Polymerase Chain Reaction swab test is the most accurate diagnostic test for COVID-19. But, RT PCR (or molecular) swab testing is more expensive and time-consuming. That’s why many people rely on the rapid antigen test instead. 

What’s the difference between these two tests?

RT PCR is a technique that looks for the viruses’ genetic material. In most cases, it uses swab samples from the back of the nose or throat. But, there are also PCR tests that only require saliva samples. 

The rapid antigen test, on the other hand, can only look for the proteins attached to the virus. It uses either nasal swabs or saliva samples. 

RT PCR vs Antigen Test: Accuracy

RT PCR COVID tests are more accurate because they are very sensitive to the genetic material of the virus. Antigen tests are less sensitive. This means a patient can be COVID-19 positive, but the antigen test can give a negative result because the patient hasn’t yet reached the test’s threshold of viral particles. 

In other words, rapid antigen tests are more likely to give patients false-negative results. 

RT PCR vs Antigen Test: Guidelines

Even though RT PCR testing is the gold standard for COVID-19 diagnosis, not everyone can afford to do it each time they suspect they have the infection. RT PCR swab testing is expensive, with a price ranging from PHP2,500 to PHP5,000. 

Having a molecular swab test done is advantageous because it casts no doubt. If you tested negative, then you can confirm that you didn’t have COVID-19 at the time of testing. On the other hand, rapid antigen tests must follow these guidelines to be valid:

  • Kits must be FDA-approved, and a trained healthcare professional has to administer the test. This is to avoid errors in sample collection and interpretation of results. 
  • The test is allowed as diagnostic testing of close contacts in communities, semi-closed or closed institutions with outbreaks, and in settings where immediate RT PCR tests are not available. 
  • It is a confirmatory test for symptomatic close contacts. There’s no need to confirm the result with a RT PCR test if you have symptoms. 
  • A negative antigen test for asymptomatic close contact is acceptable after a confirmatory molecular swab or after a second negative antigen test 48 hours after the first test. 
  • Antigen tests are most useful within 5 days of developing symptoms. 

Be Careful With Rapid Antigen Kits Online

In recent weeks, there has been an influx of rapid antigen test kits sold online. Be careful with them as the DOH has yet to release guidelines for self-testing. Additionally, all FDA-approved kits as of this writing are only for commercial use — not for self-administration. 

If you’ve been exposed to a COVID-positive patient or developed symptoms, get tested at an accredited clinic or laboratory. 

More Health News here


Hello Health Group does not provide medical advice, diagnosis or treatment.

Expertly reviewed by

Dexter Macalintal, MD

Internal or General Medicine

Written by Lorraine Bunag, R.N. · Updated Mar 16, 2022

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