Technical Bulletin 6: Toxin Dilution Recommended - Guardian R1000 Operation Manual

To: All Alexeter and Tetracore BioThreat Alert ™ Customers
Subject: Toxin Dilutions Recommended
Date: 14 March 2003
Because of the high sensitivity of Tetracore's BioThreat Alert toxin tests and the nature of the
immunoassay's response curve, care must be taken not to over-sample a toxin and to
generate a false negative result. Because of this, it is necessary for users to always run an
additional test whenever using ricin, botulinum toxin or SEB tests. The second test should be
run at a 1:40 dilution. No additional test is normally required when running anthrax,
plague, tularemia or brucella.
.
Summary:
BioThreat Alert toxin tests have a response curve that is set to give the maximum test
sensitivity. As a result, these tests can detect toxins at nanograms/ml levels. See our
specification sheets for details.
Over-sampling can saturate the immunoassay, thereby blocking the detector antibody-
antigen complex from binding to the capture antibodies. The result would be a false
negative. To avoid this problem, follow the recommendation below:
Recommendation:
Use care in sampling. Approximately a microgram of material in one milliliter of buffer
solution is sufficient to run 6 tests. When testing for toxins (ricin, botulinum toxin or SEB),
always run a second BioThreat Alert test strip, using a 1:40 dilution of the original sample.
Follow this procedure:
1. Start with your original sample in buffer solution.
2. Add one milliliter of buffer solution to a new, clean vial.
3. Add one drop of the original sample to this vial and agitate for 10 seconds.
4. Dose the additional toxin strip(s) with the 1:40 dilution.
5. Evaluate the tests as per our standard protocol. See the Guardian Reader Manual
and the Guardian Reader Testing Flow Chart for details.
If you have any questions regarding this bulletin, please contact Alexeter
Alexeter
Technical Bulletin #6
Technologies at 877-591-5571.
Alexeter Technologies, LLC
830 Seton Court, #6, Wheeling, IL 60090
phone: (847) 419-1507 fax: (847) 419-1648
www.alexeter.com
Technologies, LLC
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