[thelean12]

Your site seems to be getting hugged to death. Can you answer a few questions here:

- Is this test to see if someone currently has it, or if they have the anti-bodies and are (presumably) immune?

- What are the false-positive/false-negative rates? How does this compare to current leading tests?

- What's the cost per test? How does this compare to current leading tests?

[dvdt]

Thanks for letting me know about the site!

This is a test to see if someone has a current COVID-19 infection. The antibody tests (serological) tests are also important, but since it is estimated that only ~1% of the US has previously contracted COVID-19, it will be a while before serological testing becomes useful at a population level.

Our initial data show no false-positives and no false-negatives out of all specimens assayed. However, it is early days still and none of the leading tests have real-world data on false-positive and false-negative rates. The crucial parameter here to compare test performance is limit of detection (LOD). We showed we could detect as few as 10 molecules of virus, which is on par with the best RT-qPCR tests.

Cost is definitely an important consideration for roll-out of a widespread test. We anticipate that the cost will be about $15 per test.

[treis]

>Our initial data show no false-positives and no false-negatives out of all specimens assayed.

Your test is perfect? Color me skeptical.

[dang]

That's obviously not what he said. Please stick to the site guidelines:

"Have curious conversation; don't cross-examine."

"Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith."

https://news.ycombinator.com/newsguidelines.html

[treis]

What's the stronger interpretation?

[scrollaway]

They say they have not had false positives or false negatives. If that's not a lie, then that's not a lie. It does not mean the test is perfect, but it likely means the false result rate is low.

[treis]

Im not sure what you think the stronger interpretation is?

[dang]

That he was simply making a claim about what their initial data show. That is not a claim to perfection. Indeed, the whole point of saying 'initial' is to leave open the possibility that later data show something different.

[treis]

Personally, I don't think your interpretation is more charitable. If they think that their initial results possibly aren't correct then launching a business and claiming things like "Extremely Accurate" and "on par or better than other COVID-19 tests available" is fraudulent.

[zepto]

Dismissing the value of serological testing seems like a self-serving move.

Such tests are immediately of very high value because they allow us to understand immunity to Covid-19, and to actually validate the estimates of cases amongst those who haven’t sought treatment.

These are both of huge value regardless of the percentage of the US population estimate to have previously contracted Covid-19.

By all means market your test which seems like an awesome contribution, but please don’t do so by devaluing other important tools.

[edit: the parent post has been edited to be less dismissive without acknowledgement since I made this comment]

[edit: looks like I’m wrong about the post being edited. Sorry for that. I stand by everything else I say here:

Serological tests are useful and needed right now, not at some future stage. It’s not hard to google to verify this, and it’s irresponsible to downplay the value of a test we need now.]

[billiontoone]

I don't think we are in any way undervaluing the serological tests. A great serological test would be very useful. However, because of the indirect measurement, they tend not to be very sensitive or specific, so it is fair to say that they become more important not at the peak of the pandemic but at the post-pandemic period.

By the way, as a company, we really don't have much to gain from this test. If it does not get adopted, we'll go back to building our core business which has been growing 100% quarter over quarter. We have poured resources into the current development, because it is the right thing to do. No investor in our Series B round will take into account any non-recurring sell-almost-at-cost revenues that we get from a once-in-a-century pandemic.

[zepto]

You are downplaying the value by saying they will be useful in the future, rather than now.

This is not so. They are valuable right now.

[mrkurt]

For what? "Google for answers" isn't very helpful. It sounds like they're saying serological tests are valuable, but not viable for immediately testing a large population.

[zepto]

Answering questions about immunity is absolutely critical right now.

https://www.newscientist.com/article/mg24532754-600-can-you-...

https://www.ksbw.com/article/new-study-investigates-californ...

[petertodd]

Part of the problem with serological testing is false positives. I'm no expert, but my understanding is that the tests available may have false positive rates on the order of 0.5% to 2%

If only 1% are infected, and the false positive rate is 1%, it's quite hard to determine what the test result actually means. On the other hand, some places like New York City are already at 0.7% per-capita known positives, and they're not even able to test everyone with symptoms. Their true infection rate could very well be 10%, which serological testing could confirm.

[zepto]

Yes, which is why a better serological test would be extremely useful, the sooner the better. In no way does this undermine the value of BillionToOne’s test, but it is irresponsible for their CEO to be saying that serological tests are not useful yet when they are.

[onion2k]

Serological tests are useful and needed right now, not at some future stage.

It takes about a month before an antibody test is accurate in someone who has had a virus, so using them now would only detect cases where the person had the virus in early March. That limits the value of serological testing considerably.

[ejstronge]

> It takes about a month before an antibody test is accurate in someone who has had a virus

This is only true for the IgG class of antibodies; we typically see the IgM class of antibodies arise within 5-7 days of infection.

You are generally correct, however, in stating that antibody tests have a window in which they cannot detect a new infection.

[zepto]

Ignoring exponential growth has been a perennial mistake in handling this pandemic.

[dang]

The parent post wasn't edited.

[zepto]

Weird - I could have sworn I saw two different versions, when I pressed the back button.

But I’ll accept that I am mistaken about that.