Not sure why, but Glenn Reynolds links to this ignoramus about the it’s ricin/it’s not ricin series of events at the University of Texas.
Short version — a student there found a white powdery substance in a roll of coins. Initial state tests suggested it was ricin, but further tests by the FBI confirmed that it was not ricin. This seems to be a fairly common pattern with ricin tests, which makes you wonder why they even bother with the preliminary tests if it is so unreliable.
Anyway, this Associated Press article notes,
“There were no proteins in there to indicate it was in fact ricin,” Salinas said. He said was unlikely further testing would be done.
Texas health officials did “just a quick test and they don’t check for the proteins in ricin,” Salinas said.
This seems pretty straightforward, but not to the ignoramus blog who writes,
If they didn’t check for ricin in the first place, why are we having this discussion? Obviously, someone checked for ricin proteins… and allegedly found them.
The AP story that the ignoramus links to is poorly written and annoying, but nowhere does it claim that a) officials tested for ricin proteins, b) much less found them. That is something that the ignoramus is simply inventing out of whole cloth.
Hint: there might be a quick test for possible ricin contamination that looks for some sort of marker common in ricin but avoids actually testing for the specific protein. Perhaps this is why that AP story notes that, (emphasis added),
Preliminary tests for ricin came back positive Friday.
I was curious what sort of field tests for Ricin might exist. It turns out that the test that was likely used is something Osborn-Scientific’s ricin test. Rather than attempt to detect the ricin protein directly, which can take days, the test involves taking a sample of possibly infected material, exposing it to a culture, and then testing for the presence of anti-ricin antibodies which should emerge if ricin is really in the sample. But the test results in a pregnancy test-style readout that gives only very broad information about the possible presence of ricin.
As the detailed insert sheet for the test notes, however, there are any number of conditions, including contamination from non-ricin materials, that can cause the test to be inaccurate. In fact, as the insert notes,
1. There is a possibility that factors such as technical or procedural errors,
as well as other substances in the samples may interfere with the test and
cause erroneous results.. . .
A positive result indicates the sample probably contains
Ricin toxin above the cut-off concentration.
A number of other companies manufacture similar fast tests for ricin that use similar methods. They are useful for quick evaluations — if it tests positive, as it did here, then the people exposed need to take medical precautions — but the test is not good enough to guarantee that the sample does indeed contain ricin and it does not measure directly the presence of ricin proteins.
So how do they test for ricin once the sample is sent to a laboratory? According to the CDC,
What tests can be done for ricin in environmental samples
When a reference laboratory receives an environmental sample suspected of containing ricin, the laboratory performs specific tests to detect the presence of the agent. Tests performed on ricin-suspicious samples include the following:
- Time-resolved fluorescence immunoassay: In this test, the laboratory technicians use an antibody that binds to ricin to enable them to detect it in environmental samples.
- Polymerase chain reaction (PCR): PCR is a test used to locate and make copies of parts of the DNA contained in the castor bean plant. The search can specifically look for the DNA of the gene that produces the ricin protein.
Based on all of this, the logical conclusions is that the initial tests performed by the local officials were looking for ricin antibodies, whereas the FBI did a full PCR test which would directly measure the presence (or lack thereof) of ricin protein.
Perhaps some folks might want to rename their sites the “Why Keep On Blogging If I’m Not Going to Use My Brain or Google” Generation.