Technical Bulletin 8: Interpreting Positive Results - Guardian R1000 Operation Manual

To: All Alexeter Guardian Reader System™ Customers
Subject: Interpreting "Positive" Biological Screening Results
Date: 24 April 2003
An Automatic Mode test is required to obtain a positive biological screening from the
Guardian Reader System. Users of the Guardian Reader System must avoid interpreting
"positive" results prematurely, especially if interpreting based solely on the results of a
Manual Mode test. Premature interpretation contradicts Alexeter's training and published
protocols. Valid results can only be obtained by following Alexeter's full testing protocol,
which is summarized on the Guardian Reader System Testing Flow Chart.
The Guardian Reader Manual, the Guardian Reader System Testing Flow Chart, all
Technical Bulletins and Refresher training are posted on Alexeter's Web site:
www.alexeter.com.
Summary:
Per Alexeter's training and protocols, a positive result can only be obtained by running an
Automatic Mode test. There are important reasons for this:
Manual Mode tests are the "first screening" at the scene, providing the user with the
•
flexibility to screen for multiple biological agents in parallel. This means that 7 tests can
be completed in just over 30 minutes. Otherwise, 7 Automatic Mode tests, run in series,
would take about 2 hours.
Manual Mode tests rely on user-timing during field operations. Because this timing must
•
be correct to obtain valid results, a "positive" result in Manual Mode is not considered
definitive and must be followed by an Automatic Mode test to validate the result.
• Automatic Mode tests remove timing responsibility from the user, thereby reporting
results after precise timing, allowing the user to concentrate on other tasks at the scene.
Guidelines:
1. Prepare the sample by sampling moderately. You only need about a microgram of
material, dispersed in 1 ml of buffer solution to meet the sensitivity requirements for the
BioThreat Alert™ tests. Please review the sampling procedures at our website.
2. Check the sample pH. pH values outside the range of 4 to 10 indicate the presence of
strong acids or bases and the likelihood of over-sampling. If the pH is out of range,
prepare a 1:4 dilution.
3. Dose multiple test strip types. This helps ensure you do not miss an unexpected
biological agent and also helps diagnose possible chemical interference. Write the
dosing time on each test.
Alexeter
Technical Bulletin #8
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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