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Table 5 Measures of performance of microarray findings using normalization incorporating the external control features, compared to not incorporating the external control features.

From: Novel design and controls for focused DNA microarrays: applications in quality assurance/control and normalization for the Health Canada ToxArray™

A. Using all microarray pairwise comparisons
  Microarray result using EC Normalization Microarray result NOT using EC normalization
RT-PCR result: Significant Not Significant Significant Not Significant
Significant 11 a 3b 8a 9b
Not Significant 3c 10d 6c 4d
Sensitivity 78.6% 57.1%
Specificity 76.9% 30.8%
Positive Predictive Value 78.6% 47.1%
Negative Predictive Value 76.9% 40.0%
Efficiency of the test 77.8% 44.4%
B. Using microarray pairwise comparisons that were in disagreement
  Microarray result using EC Normalization Microarray result NOT using EC normalization
RT-PCR result: Significant Not Significant Significant Not Significant
Significant 5 a 1b 2a 7b
Not Significant 3c 10d 6c 4d
Sensitivity 62.5% 25.0%
Specificity 90.9% 36.4%
Positive Predictive Value 83.3% 22.2%
Negative Predictive Value 76.9% 40.0%
Efficiency of the test 79.0% 31.6%
  1. Sensitivity= TP/(TP+FN); Specificity = TN/(TN+FP); Pos. Predictive Value= TP/(TP+FP); Neg. Predictive Value = TN/(TN+FN); Efficiency = (TP+TN)/(TP+TN+FP+FN).
  2. a True Positive; b False Negative; c False Positive; d True Negative