nal von minden NADAL Strep A Test Instructions D'utilisation page 8

ENGLISH
12. Expected Results
It is known that approximately 19% of all upper respiratory
tract infections are caused by Group A Streptococci. Such
infections are most prevalent in winter and early spring, with
most cases arising in patients living in highly populated areas.
13. Limitations
 The accuracy of the test depends on the quality of the swab
sample. False negatives results can originate from improper
sample collection or storage.
 A negative result can also be obtained from patients at the
onset of the disease due to low antigen concentration.
Therefore, when a patient is suspected of having Strep A
Pharyngitis however has a negative NADAL® Strep A test
result, additional testing using a culture should be pre-
formed.
 The test does not differentiate asymptomatic carriers of
Group A Streptococcus from those with the infection. If
clinical signs and symptoms are not consistent with labora-
tory test results, a follow-up throat culture is recommend-
ed.
 In few cases, test specimens heavily colonized with Staphy-
lococcus aureus can yield false positive results.
 Respiratory infections, including pharyngitis, can be caused
by Streptococci from serogroups other than Group A, as
well as by other pathogens.
 As in the case of any diagnostic procedure, the results
obtained with this test should be used in conjunction with
other information available to the physician.
14. Performance Characteristics
Sensitivity (Detectable Limits) Study
To determine the analytical sensitivity of the NADAL® Strep A
Test cassette, Group A Streptococcus bacteria organisms were
cultivated by standard culture techniques. The detection limit
of the NADAL® Strep A Test cassette was determined to be
5
1.5×10 organisms per test.
Specificity Study
To determine the specificity of the NADAL® Strep A Test
cassette to Group A Streptococcal bacteria, the following
Group A Streptococcal strains at different levels of organisms
per test were examined. Positive results obtained at level of
5
1.5×10 organisms/test for all strains indicate that NADAL®
Strep A Test cassette is sensitive to Group A Streptococcal
bacteria:
Group A Streptococcal strains
SS-091; SS-410; SS-492; SS-496; SS-633; SS-634, SS-635, SS-
721; SS-754; SS-799; ATCC-19615;
Cross-reactivity studies
Cross-reactivity studies with organisms likely to be found in
the respiratory tract were also performed using the NADAL®
Strep A Test cassette. The following organisms were tested at
8
1×10 organisms/test.
The NADAL® Strep A Test cassette gave negative results in all
cases.
nal von minden GmbH • Carl-Zeiss-Strasse 12 • 47445 Moers • Germany • info@nal-vonminden.com • www.nal-vonminden.com
NADAL® Strep A Test (test cassette)
(Ref. 222001A)
Bordetella
pertussis
Candida albicans
Corynebacterium diphtheriae
Escherichia coli
Haemophilus
parahaemolyticus
Moraxella catarrhalis
Neisseria gororrhoeae
Neisseria lactima
Neisseria meningitidis
Neisseria sicca
Neisseria subflava
Proteus vulgaris
Pseudomonas aeruginosa
Staphylococcus aureus
Staphylococcus epidermidis
Correlation Study
The correlation study between the NADAL® Strep A Test
cassette and a conventional culture was performed in multiple
clinical centres. Throat swab specimens were taken from
children and adults exhibiting symptoms of pharyngitis. The
swabs were then used to inoculate blood agar plates prior to
testing with the NADAL® Strep A Test. Beta-hemolytic colonies
from the blood agar plates were confirmed as Group A Strep-
tococcus using serologic streptococcal grouping methods.
Strep A was reported as present or not present. Quantification
was not performed during testing of clinical samples.
The results are summarized as follows:
+
Culture
--
Total
Sensitivity: 97.6% (95% Cl,93.8% to 99.4%)
Specificity: 97.5% (95% Cl,93.7% to 99.3%)
Positive predictive value (PPV): 95,3%
Negative predictive value (NPV): 98,7%.
Accuracy: 97,5%
You receive within 5 minutes 238 right results of 244 patients
without doing a culture (97.5%).
Physician Office Laboratory Studies
An evaluation of NADAL® Strep A Test was conducted at three
Physician Office Laboratory sites, using a panel of coded
samples containing negative controls, weak positive samples
and middle positive samples. Each specimen level was tested
in replicates of five, at each site, over a period of five days.
One hundred percent (100%) agreement with the expected
results was obtained
Staphylococcus
saprophyticus
Streptococcus bovis
Streptococcus faecalis
Streptococcus faecium
Streptococcus Gruppe B
Streptococcus Gruppe C
Streptococcus Gruppe D
Streptococcus Gruppe F
Streptococcus Gruppe G
Streptococcus mitis
Streptococcus mutans
Streptococcus pneumoniae
Streptococcus salivarius
Streptococcus sanguis
NADAL® Strep A test
cassette
+ --
82 2
4 156
86 158
Total
84
160
244
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