Wednesday, May 21, 2008

Urinalysis another example of forensic science with subjective results

The rate of positive results on urinalyses at the Bexar County probation department jumped fourfold after the private lab doing the tests changed their procedures in February, reports KSAT in San Antonio:
On Monday, the president of the Central Texas Association of Public Employees and a Bexar County probation officer said the high numbers of positives were alarming."Confirmation has come back to the department and we're concerned about those, and also, a lot of defendants on their own have gone out and had hair follicle tests in other labs to confirm their suspicions," Sheri Simonelli said.
Here's another great example of the subjectivity of forensic science. In this case, there exist no concrete standards for how to measure urinalysis results. Reports KSAT, "Jeff Warner, the owner of Treatment Associates, said a test used before a February switch wasn't aggressive enough, and has led to a 35 percent jump in positive drug tests. He said the county's probation department was using an outdated test and an unguarded urine specimen process."

Normally one doesn't think of judging a scientific metric by whether it's "aggressive," but whether it's "accurate." I have no way of knowing which standard lies closer to the truth. But if a change in (unregulated) testing protocols resulted in such dramatic a difference in results, the disparity demonstrates once again how large the error rate can be in common forensic science techniques that most people consider reliable.


Anonymous said...

This guy warner is using the tox-cup which is a preliminary test. The test may be a good first line test but not for court. Chief Probation Officer Fitzgerald should not be using this for Motions To Revoke. How many are in Jail??? Grits, should you order these confirmation under open records??? The confirmation tests should be positive or those officers are very very right with the whistleblow. How about those poor probationers sitting in jail on a preliminary test. This is very sad. Check out the female probationer on the site under video on demand, who states she was jailed under this Chief Fitzgerald lab tests. I smell a big civil rights suit. Where are the county commissioners in all this- no control over Bexar County????

kbp said...


I had commented on a testing related post of yours and asked if you followed the Duke case any.

My knowledge is basics I have learned reading some, questioning a few that do the testing and following cases.

In the Duke the state lab took samples from false nails and ran auto-somal STR, coming back with totally inconclusive results. Definately not enough markers.

Then DNA Securities, using the exact data, came up with "not excluded", with IIRC, 2 or markers that would did not exclude.

The sample was a mix brewed up from swabbing ALL the nails into a single sample.

The point here is that Multiple people, very familiar with the testing, read the results from both labs.

Lab 2 was using data from lab 1 on the same program, getting different results.

All agreed the only way they knew such could happen was for lab 2, DNA Securities, to have tweaked the programed parameters to read the data differently.

I see it as a prime example of that "subjective" problem.

To top it off, DNA Securities Inc. classified results showing full profiles of UNKNOWN MALES in their Y-str results report as 'NON-PROBATIVE" and then tried to call the only report ever presented an "INTERIM REPORT", based on what the DA told them he wanted results for.

EVERY defendant needs an expert to read 100% of all lab data today.

Of course that is in criminal trials and not job UA's!

Anonymous said...

Shouldn't drug test results be expressed something like:

Detected X ppm drug/metabolite with +/- Y% certainty

Gritsforbreakfast said...

But even then, at what "X" do you declare the test "positive," I think is the question, 1:57. As I understand it, it's not enough to search for a trace, because other substances can create false positives. So how many ppm gets you to "Yes"? If you lower that threshold, you might get both fewer false negatives and simultaneously MORE false positives.

I think the hair follicle tests are considered more accurate, but they're too expensive for routine use at the volume needed by the probation department.

KBP, good example on the subjectivity question and DNA. A lot of DNA sample are contaminated and require a judgment call by experts, according to a presentation I saw recently from the head of the Houston crime lab. The more I learn about forensic science, the more I think we may trust the folks in the white lab coats just a bit too readily.

rericson said...

Just a bit of anecdotal stuff...
I recently was involved with a 15 yr. old male on probation for a minor juvenile offense....posession....very, very small quantity...but it was drug related so part of his probation requirement was regular urine testing....well, one Friday afternoon, went in for his peeing in a cup routine and went home...the following tues.his probation officer came to school and took him into custody for a violation...he had a hot pee for opiates....while in detention, awaiting his hearing, he was retested...still showed opiates but to a lesser this kid was CLEAN!!!.....after much ado, turned out he had eated close to a dozen poppy seed bagels over just a few days.....and ate one everyday for breakfast......
He's out with huge appologies from his jpo......

Anonymous said...

There was a Mythbusters episode where Jamie ate bagels and Adam ate poppy-seed cake. Both tested positive for opiates for quite a number of hours.

Excerpt from
The Discovery channel program Mythbusters put the poppy seed claim to the test, feeding mythbuster Adam an enitre loaf of poppyseed cake and Jamie three poppy seed bagels. Tests were administered every half hour, and Adam tested positive after the first test. Jamie was slower, taking two hours to test positive after eating the bagels. Both tested positive for the remainder of the day, but were clean the next morning, 18 hours later. Myth status: confirmed.

You can download the Mythbustes poppy seed episode for $1.99 from the Discovery Channel Store web site.

Anonymous said...

The test results should be a ratio like when your vision is rated at 20/20.

[amount detected]/[failure amount]

15/20 would be a No
20/20 would be a minimum Yes
40/20 would be a big Yes

If it was done like this we could probably figure out by looking at the averages across people if the San Antonio increse was due to "agressive" failure policies or a change in behavior of the detection equipment.

Gentlemen, we can rebuild these tests. We have the technology. Better, stronger, faster.

Anonymous said...


Sheri Simonelli has now been placed on 5 days admin. leave pending termination for speaking out as president of our association. She has tried very hard to protect the officers and probationers. I feel the department is acting very irrational here and is trying to cover their tracks to silence what they have done with the UA results.
Can you Help us????

Anonymous said...

The on-site tests may yield a postive result due to the sensitivity, and a confirmation may yield a negative result based on a higher threshhold standard.

No one is speaking about why violations are reported to the court prior to confirmations or admissions.

Some offenders are obviously using, while other offenders could be innocent of drug use (especially the meth results).

Who knows? Big meth user state, who is guilty and who is innocent? These false positives are crazy to determine who is who.

Why are officers discouraged from asking for confirmations from this lab? Bexar County administration?

Civil rights issues? When in doubt, I want to side with caution.

Who is really running the show in Bexar County?

Judges need to finally put an end to this mess.

Anonymous said...

Again the message from the Chief/Admin is "Piss on the officers! Remember, Deputy Chief Paul Koserowski stated, " DON'T MAKE A CAREER OUT OF THIS JOB."

Anonymous said...

Yea, didn't he and his partner in crime both retire from Arizona before coming here? Career what career? It is a shame that now probationers and probation officers are both denied GUARANTED CONSTITUTIONAL RIGHTS in relation to this fiasco. Only time will tell if the judges and public put up with this. Maybe, Federal Judge Xavier Rodriguez should take a closer look at that pending Federal RETALIATION lawsuit, instead of believing the LIE that the Texas Attorney Genera told him.l