FSRU, Table 1

Table 1. Results of the Evaluation of Six Hand-held Assays for the Detection of Anthrax (B. anthracis)
and Plague (Y. pestis)

Organism
Supplier
Sensitivity Specificity# Repeatability* Robustness** Stability
B. anthracis
 
Unpurified spores
Washed spores
   
No target
Target
 
1
106
108
1/30
97/99
20/20
17/20
+
 
2
105
105
10/30
86/99
18/20
17/20
+
 
3
105
106
25/30
93/99
17/20
17/20
+
 
4***
105
n.d.
7/17
21/27
n.d.
n.d.
n.d.
Y. pestis
 
37° C
25° C
 
 
 
 
 
 
5
105
n.r.
1/15
99/99
20/20
20/20
+
 
6
104
n.r.
2/15
97/99
97/99
17/20
+

(#) All HHAs tested positive to some degree with vegetative cells, which are the progenitor of the spores,
but the results are not included in the data reported here. Also, the false-positive results obtained with
interferents in the absence of target organisms are not included here. In these studies, 107 spores or cells
were used.

(*) The repeatability is the ratio of the number of sets of replicates that yielded identical results for each ticket
relative to the total number of sets examined.

(**) The robustness of the assay is reported as the number of times the HHA yielded expected results
relative to the number of tests performed.

(***) The evaluation of these HHAs was terminated midway in the project because the testing required too
much total time. Each test had to be analyzed with a fluorescence reader, and only one strip could be
analyzed at a time, which took 15 minutes. Thus, 10 tests would require at least 150 minutes total analysis
time. In addition, if the wicking of the solution along the pad did not occur within the correct time interval,
the reader automatically aborted the test. Slow wicking was observed with a number of the strips used in this
study, so the experiments had to be repeated. The sensitivity of these devices was obtained from examining
a series of two replicates, instead of from the stringent test.

(+) Stable up to 86°C

n.d. = Not determined

n.r. = No reactivity observed

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