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Vivalytic Bordetella
– Instructions for Use
Analytical Performance Evaluation
Analytical Sensitivity (Limit of Detection)
The limit of detection (LoD) of the Vivalytic Bordetella test was determined
as the lowest concentration of analyte that can be consistently detected
(≥ 95 % of samples tested under routine laboratory conditions using a
defined type of sample, Table 1).
Inclusivity
To evaluate inclusivity, an in silico analysis (BLAST alignment) of the genom-
ic sequence of various relevant Bordetella pertussis, Bordetella parapertussis
and Bordetella holmesii strains against the sequence of the PCR primers and
hydrolysis probe used in the Vivalytic Bordetella test for amplification and
detection of the respective pathogens was performed. Inclusivity could be
shown for organisms listed in Table 2.
Exclusivity / Analytical Specificity
To exclude cross-reactivity (exclusivity), an in silico analysis (BLAST align-
ment) of the target region of Bordetella pertussis, Bordetella parapertussis
and Bordetella holmesii against the genomic sequence of various other
pathogens representing common respiratory pathogens or closely related
species was conducted. For the detection system of Bordetella pertussis,
sequence matches in the probe and primer area could be detected for the
Bordetella bronchispetica strains NCTC10543, MBORD731, NCTC8344,
E001, MBORD595, concluding a possible amplification. For the detection
system of Bordetella parapertussis, sequence matches in the probe and prim-
er area could be detected for the Bordetella bronchispetica strains KM22,
BB5, FR3523, FR2017, FR3823, concluding a possible amplification. There
was no evidence of an interference for the detection system of Bordetella
holmesii (Table 3).
Reproducibilty
The reproducibility of the Vivalytic Bordetella test was established using
a panel with 3 different concentrations of Bordetella pertussis, Bordetella
parapertussis and Bordetella holmesii. At 3 test sites, each mix was tested on
the same set of Vivalytic instruments by the same operator with 3 LOTs in 4
replicates on 3 days, respectively. The obtained positivity rates for the differ-
ent combinations were correlated to the expected positivity rate (Table 4a).
Repeatability
The repeatability of the Vivalytic Bordetella test was established using
a panel with 1 concentration (3x c95) of Bordetella pertussis, Bordetella
parapertussis and Bordetella holmesii. At 1 test site, the mix was tested on
the same set of Vivalytic instruments by the same operator with 3 LOTs in
20 replicates, respectively, yielding in a total of 60 observations per target
pathogen. The obtained positivity rates for the different combinations were
correlated to the expected positivity rate (Table 4b).
Interferences
Interferences were evaluated for endogenous and exogenous substances,
that are potentially present in the patient sample. Refer to Table 5 for sub-
stances that have the potential to interfere with the test. No interferences
were detected.
Clinical Performance Evaluation
Sensitivity and specificity results derived from native nasopharyngeal swab
samples. Samples were collected in a clinical setting and compared with
results of reference methods.
561 nasopharyngeal swab samples in eNAT were tested at one study site
using a screening approach with potentially clinical positive samples. 8
clinical samples were found positive for one of the three pathogens (all Bor-
detella parapertussis) leading to a positive rate within the sample set of 1.9%
(8/411). Additionally, 150 negatively pre-characterized samples were spiked
with respective reference material (50 sample per pathogen).
In total, 495 results were included in the data set gained from testing with
a reference test (Bordetella Speciation Plus Toxin - OSR for BD MAX™) and
Vivalytic Bordetella, leading to the performance results shown in Table 6.
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