My son's camp allows for the antigen or PCR test prior to coming to camp. If we have not knowingly been exposed and he is healthy which one should we do? What are the differences? Thanks in advance.

Typically the antigen test is testing for viral protein while the qPCR test is testing for viral genome

The main difference is in sensitivity. They are both very specific, meaning a positive in either is almost always a true positive.

The qPCR test is more sensitive and thus less likely to produce a false negative.

But the antigen test is much faster.

Those are the main differences and trade-offs.

Thanks. Is one more invasive than another?

PCR is nasal swab
Antibodies is finger *****.

Finger Pr1ck
Texag censors!

Antigen is going to show that you've gotten it at some point, but don't necessarily currently have it. Whereas PCR is going to show that you currently have it, right?

My 18 yr old son just had an antibody test today, at Walgreens/LabCorp. He said it was a venipuncture blood draw , enough the size of his index finger he said. I thought that was alot of blood, I was told it was going to be a finger *****. Anyway, maybe that gives them a higher % of correct positive/negative, I don't know. They didn't even tell him how long until he got the results, said he was there like 2 minutes.

Not quite.

Antigen and genome (qPCR) are going to show you currently have virus, either protein or genome.

You're thinking of the third kind of test which is antibody. That will show you've had it in the recent past.

To help with the confusion going on here, there are 3 types of tests:

qPCR (tests for viral RNA)
Antigen (tests for viral protein)
Antibody (tests for antibodies produced by your body specific to SARS-CoV-2)


qPCR and antigen tests are directly testing for virus parts. These are both meant to diagnose an active viral infection. And they're both done using nasal swabs and in some cases (not sure if it's approved yet), saliva or oral swabs.

The antibody test is done using a blood draw and is meant to confirm a past infection since it takes a week or so post infection for the body to develop antibodies.

I was told that they now count the antibody test in the new case numbers. Is this true?

DrZ said:

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I was told that they now count the antibody test in the new case numbers. Is this true?

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Initially Texas reported them all together a couple of months ago. They were rightfully told how stupid that was since they are fundamentally different in what they're testing for.

They changed to reporting the qPCR and antigen tests separately from the antibody tests.

So positive antibody tests are reported as "new" cases in the sense that it does represent a newly discovered case.

It's not reported as a "current" case since a positive antibody test does not mean there is an active infection at the time.

Well, they don't break that down on the news. So when they report xxx New Cases, that means antigen plus antibody?

Honestly, I don't watch the news, so I'm not sure.

I can tell you for the Texas Med Center data, our "daily new positive cases" are only qPCR assay tests.

But outside of that, I don't know where the news sources are getting their numbers.