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A minimum of 5 dry swab results were available for each DiagCORE Respirary Panel 2 pathogen.
Parainfluenza Virus 4 and Legionella pneumophila formed an exception as only 3 and 2 results
respectively were avaialble.
Similar as above , the Clinical sensitivity or PPA was calculated as 100% x (TP / TP + FN). True positive
(TP) indicates that both the dry swab and the UTM specimen had a positive result for a specific
organism, and false negative (FN) indicates that the dry swab result was negative while the UTM
specimen result was positive. Specificity or NPA was calculated as 100% x (TN / TN + FP). True
negative (TN) indicates that both the dry swab and UTM specimen had negative results, and a
false positive (FP) indicates that the dry swab result was positive but the UTM specimen result was
negative. The exact binomial two-sided 95% confidence interval was calculated for each point
estimate
For all dry swabs, a total of 440 results were available for analysis. Overall Clinical Sensitivity or PPA
could be calculated from 244 results. The overall Clinical Specificity or NPA was calculated from
196 results . In total 241 true positive and 188 true negative dry swab results were found, as well as
3 false negative and 8 false positive dry swab results.
Because the same sample is tested, the dipped swab may be considered to be most relevant with
regard to assessing equivalency of the dry swab with the UTM specimen performance. Testing of
the dry swab involves taking 2 samples from the same patient and although paired, a bias may
occur due to this approach. Also, as the nasopharyngeal swab collection does present a level of
discomfort for the patient it is likely that the yields obtained between the 2 collections may differ.
For all dipped swabs, a total of 337 results were available for analysis. Overall Clinical Sensitivity or
PPA could be calculated from 178 results. The overall Clinical Specificity or NPA was calculated
from 159 results . In total 177 true positive and 156 true negative dipped swab results were found,
as well as 1 false negative and 3 false positive dipped swab results.
Table 3. DiagCORE Respiratory Panel 2 Sensitivity and Specificity characteristics with 95%
Confidence Intervals for dry swab specimen
All Dry Swabs
Dipped Swabs
11.2 Conclusion
This extensive multicentre study seeked to assess the performance of the UTM specimen as well as
the equivalency of the dry swab with the UTM specimen performance in the DiagCORE Respiratory
Panel 2 assay.
The overall Clinical Sensitivity of the UTM specimen was found to be 97.3% (95% confidence interval
95.4%-98.4%). The overall Clinical Specificity in 190 full negative samples was 98.4% % (95%
confidence interval 95.5%-99.5%).
DiagCORE Respiratory Panel 2
TP/
Sensitivity
TP+FN
241/244
98.80%
96.4%-99.6%
177/178
99.40%
96.9%-99.9%
TN/
95% CI
Specificity
TN+FP
188/196
95.90%
156/159
98.10%
DiagCORE Respiratory Panel 2 Instructions for Use
95% CI
92.2%-97.9%
94.6%-99.4%
49
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