FDA publishes antibody test performance characteristics - Printable Version
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FDA publishes antibody test performance characteristics - BostonCard - 05-08-2020
About a dozen different tests are included. The FDA publishes sensitivity, specificity, and positive predictive value in a 5% prevalence scenario, with confidence intervals.
https://www.fda.gov/medical-devices/emergency-situations-medical-devices/eua-authorized-serology-test-performance
All the tests listed have EUA’s.
BC
RE: FDA publishes antibody test performance characteristics - M T - 05-10-2020
Thanks.
Now that I, as a layman, have sorta understood IgG and IgM, what is pan-Ig?
I find it interesting that Roche & Abbott have put this out with relatively few (< 100) tests against known cases. I am pleased they've tested >1000 known negatives.
RE: FDA publishes antibody test performance characteristics - BostonCard - 05-10-2020
Pan-Ig refers to all immunoglobulin subtypes. In other words, it’s not specific for IgG or IgM.
BC
RE: FDA publishes antibody test performance characteristics - M T - 05-10-2020
A chart FOR ILLUSTRATIVE PURPOSES ONLY that I found useful is in
http://www.diazyme.com/covid-19-antibody-tests
showing the relation of the IgG, IgM,
(The levels and days are illustrative and not necessarily real.)
I was listening to a This Week in Virology (#608) a few days ago. It seems that the first week after symptoms arrives is usually not threatening (but the person is shedding the virus the most, and is most infectious).
Toward the latter part of the 2nd week is when decompensation may occur (8:20 in that audio, more at 17:05) and you can go downhill very fast (so, don't wait to get into care!) with breathing issues (the pneumonia). By this time, the viral levels are much lower.
Beyond the end of the 2nd week (possibly independent of the severity of breathing issues) may include clotting problems (thrombosis, strokes, etc.) This is at 19:35 in the audio. By this point, the virus is pretty much gone. [Reminder: don't change meds except by consultation with your doctor.]
There is a good bit of discussion (beginning about 22:00) about the completed remdesivir trial from Wuhan (no significant effect) and the teaser of reduced time to recovery for the not-yet-finished trial (Gilead trial, reported by NIH). I believe Stanford Hospital is one of many sites in this trial.
Remdesivir is an anti-viral. If you start treating with it when decompensation occurs and the viral levels are already low, how much good can it do? So the question would seem to be, will it be beneficial for high-risk individuals if given shortly after symptoms occur?
Btw, in a discussion I was in, the question came up that essentially was "If I come down with symptoms, why should I bother getting a test? There's really no change in treatment, is there?"
In case anyone else is thinking that....
1) If you test positive, you will probably be more cautious about risking others (often those in your household) by exposing them, and they will treat it more seriously. No thoughts of "Well, he might not really have it."
2) If those you've been in contact with may choose to self-isolate KNOWING that you have the disease and may have exposed them. That may save the life of someone that they could have exposed otherwise.
3) As described above, if you have the disease, your condition may turn much worse within hours (think Saturday 10PM). You want to have done all the things so you can seek medical care immediately and have the information (medical, insurance, etc. Now, even if you don't get the pneumonia, you want to know to be on the look out for the circulatory problems.
RE: FDA publishes antibody test performance characteristics - magnus - 05-10-2020
Wasn't there that article about the pulseox that recommended lying on your stomach or side to help after early diagnosis?
RE: FDA publishes antibody test performance characteristics - BostonCard - 05-10-2020
(05-10-2020, 07:25 PM)magnus Wrote: Wasn't there that article about the pulseox that recommended lying on your stomach or side to help after early diagnosis?
Ventilated patients are sometimes placed in the prone position (on their stomachs) in order to better match ventilation (where the air goes) with perfusion (where the blood goes). In the lung, blood naturally pools towards the back if someone is lying supine. But that might be a part of the lung that is significantly affected by COVID-19, so blood might be pumped to a portion of the lung that is not getting oxygen. Prone positioning can help with that.
I guess it is the same idea earlier in the diagnosis.
Note, there is no guarantee that the anterior lungs (the front, which would get more blood flow in the prone position, as they would be on the bottom) would be better ventilated than the posterior lungs. So, it could help, but it might not.
BC