What are "Probable Cases/ATK" and is it hiding cases?

[djay]

as presented on the https://ddc.moph.go.th/covid19-dashboard with the literal translation being "Probable Cases".

[djay]

"Probable cases" is a bad translation from the thai. What it represents is some subset of positive ATK results. Thailand only includes PCR positive as being a "confirmed case".

Advice from doctors I've talked is that this number represents those registered for home isolation based on ATK positive result alone.

• Thailand only uses PCR to confirm a case (MOPH says this is a WHO recommendation)
  • Most countries don't include ATK positives in their confirmed case numbers. Malaysia and England are two exceptions.
• NHSO are now doing large amounts of free ATK testing
  • possibly replacing proactive PCR testing which has reduced. ATK is a lot cheaper than PCR.
• If ATK positive and symptoms are severe or they can't isolate at home they will take a PCR test and enter the hospital system.
  • We don't know the number of probable cases that become confirmed cases so we can't add the two numbers togeather
• Use of ATK could be decreasing OR increasing confirmed case numbers
  • Thailand wasn't detecting many cases before ATK's had wide spread use. It's possible that with some ATK positives following up with a PCR test and becoming a confirmed case that the case numbers are now larger than they would have been without ATK. esp since PCR tests were very hard to get when capacity was reached.
• There is another number of ATK positives from free HNSO provided tests. It's not the same and it's not clear why.
  • 
  • the do know that it's positive rate is much lower so likely being used to filter the PCR tests perhaps replacing PCR proactive testing
  • 
• False positives from ATK are low (1-2%) and 2-3 tests makes them as accurate as PCR tests (helps reduce false negatives)