Peter Bol's doping suspension lifted - B sample comes back "atypical"

Zoom Rival MD wrote:

rekrunner wrote:

+1

Both EPO tests for urine seems to be prone to errors (false negatives and false positives). The study you linked earlier says that both tests for EPO have "a false presumptive finding rate of 4.3% and 6%" -- i.e. known false positives. Conducting a B-sample test with the same false positive rate, means the expected false positives will be 0.2% and 0.36% -- maybe not enough for a false positive in 100 samples, but we can expect a few B-sample confirmed positives over thousands of tested samples.

Completely incorrect.

They do a screening test to see which samples MIGHT test positive, and the rest they can sign off on. This means they can efficiently eliminate all the clearly negative samples, they can focus on only the few suspicious ones for the actual confirmation testing and determination or not of an adverse finding.

This is the process of testing ONE sample. If there was an adverse finding and the athlete wants to test the B it goes through the entire process again

You geniuses are quoting the results of the screening test. When you come to these conclusions do you not stop to think whether it is even remotely plausible. You're claiming essentially one in every 20 A samples in clean athletes would test positive. Wasn't Bol alone was tested 20 plus times last year. Everyone would be getting done

So, once again, the ACTUAL false positive rate shown by the EPO test in the study is ZERO.

Wise Old Man wrote:

Zoom Rival MD wrote:

Completely incorrect.

They do a screening test to see which samples MIGHT test positive, and the rest they can sign off on. This means they can efficiently eliminate all the clearly negative samples, they can focus on only the few suspicious ones for the actual confirmation testing and determination or not of an adverse finding.

This is the process of testing ONE sample. If there was an adverse finding and the athlete wants to test the B it goes through the entire process again

You geniuses are quoting the results of the screening test. When you come to these conclusions do you not stop to think whether it is even remotely plausible. You're claiming essentially one in every 20 A samples in clean athletes would test positive. Wasn't Bol alone was tested 20 plus times last year. Everyone would be getting done

So, once again, the ACTUAL false positive rate shown by the EPO test in the study is ZERO.

Link:www.ncbi.nlm.nih.gov/pmc/articles/PMC6...

What we don’t actually know is the testing process in the real world, or do we?. If the A sample is run once and there is a clear cut band indicating exogenous epo, and then the A sample is run again independent of the first run, and there is a clear and identical band to the first run, and only under these circumstances is the A sample deemed positive, then yes, that would be in keeping with the quoted study. Then of course, you need to run the B sample twice and each time get a clear, matching band, also matching the A sample, for the athlete to have an AAF. Do we know that’s how it’s done? That strikes me as the stringency level required at a minimum to call out a positive when the consequences are so dire. Though doping is a scourge on the sport, it’s imperative that the tests be run and interpreted in a manner that sets the specificity as close to possible at 100% even if it means sacrificing sensitivity. You agree with this, right? Reading between the lines, it seems that Bol’s results are not going to meet this standard. I’m not a biochemist, just a fan, but the more I read about the epo assay, the more it seems squishy.

rekrunner wrote:

Zoom Rival MD wrote:

Completely incorrect.

They do a screening test to see which samples MIGHT test positive, and the rest they can sign off on. This means they can efficiently eliminate all the clearly negative samples, they can focus on only the few suspicious ones for the actual confirmation testing and determination or not of an adverse finding.

This is the process of testing ONE sample. If there was an adverse finding and the athlete wants to test the B it goes through the entire process again

You geniuses are quoting the results of the screening test. When you come to these conclusions do you not stop to think whether it is even remotely plausible. You're claiming essentially one in every 20 A samples in clean athletes would test positive. Wasn't Bol alone was tested 20 plus times last year. Everyone would be getting done

So, once again, the ACTUAL false positive rate shown by the EPO test in the study is ZERO.

Sure, that study says they didn't seek a second opinion, nor send it it WADA experts, as would be the case in the real world.

But forgive me if I guard my scepticism when an anonymous poster on the internet tries to convince me something has a ZERO% false positive rate, and then links to a study in 2019 which says "As data on the performance of these methods are incomplete ..."

Maybe in practice, false positives can be reduced by multiple testing of the A-sample for confirmation, and ultimately sending it for re-evaluation to "a WADA‐recognized expert", from a select pool of experts who "have extensive scientific knowledge of ... potential issues in the detection of ESAs".

But all these steps are not necessary if the lab testing itself didn't produce a non-negligible rate of "false presumptive findings".

We are left with, not trusting the objective science, but trusting the competence, objectivity and aligned motivations, of a small pool of WADA-accredited lab technicians, and WADA-experts, whose results and criteria are not easily made available for independent corroboration to the accused.

Quote...

rekrunner wrote:+1Both EPO tests for urine seems to be prone to errors (false negatives and false positives). The study you linked earlier says that both tests for EPO have "a false presumptive finding rate of 4.3% and 6%" -- i.e. known false positives. Conducting a B-sample test with the same false positive rate, means the expected false positives will be 0.2% and 0.36% -- maybe not enough for a false positive in 100 samples, but we can expect a few B-sample confirmed positives over thousands of tested samples.

Zoom Rival MD wrote:

rekrunner wrote:

Sure, that study says they didn't seek a second opinion, nor send it it WADA experts, as would be the case in the real world.

But forgive me if I guard my scepticism when an anonymous poster on the internet tries to convince me something has a ZERO% false positive rate, and then links to a study in 2019 which says "As data on the performance of these methods are incomplete ..."

Maybe in practice, false positives can be reduced by multiple testing of the A-sample for confirmation, and ultimately sending it for re-evaluation to "a WADA‐recognized expert", from a select pool of experts who "have extensive scientific knowledge of ... potential issues in the detection of ESAs".

But all these steps are not necessary if the lab testing itself didn't produce a non-negligible rate of "false presumptive findings".

We are left with, not trusting the objective science, but trusting the competence, objectivity and aligned motivations, of a small pool of WADA-accredited lab technicians, and WADA-experts, whose results and criteria are not easily made available for independent corroboration to the accused.

Quote...

rekrunner wrote:+1Both EPO tests for urine seems to be prone to errors (false negatives and false positives). The study you linked earlier says that both tests for EPO have "a false presumptive finding rate of 4.3% and 6%" -- i.e. known false positives. Conducting a B-sample test with the same false positive rate, means the expected false positives will be 0.2% and 0.36% -- maybe not enough for a false positive in 100 samples, but we can expect a few B-sample confirmed positives over thousands of tested samples.

This is one for the books, folks

I literally just linked the study that you were quoting. Those exact numbers 4.3% and 6% are from it.

Anyway not trying to convince you of anything, just pointing out literally what YOUR beloved study actually says.

But carry on arguing with yourself why your own study sucks