• Test performance parameters include:
• Sensitivity: the probability that the test will produce a positive result from an infected individual. Measures the ability of the test to detect its intended analyte
• Specificity: the probability that a test will produce a negative result from an individual that is not infected. Measures the ability of the test to distinguish between its intended analyte and other targets
• Predictive Value combines the above performance parameters with disease prevalence in the population
• Positive Predictive Value (PPV): The probability that a person is infected when a positive test result is observed (the chance that a positive result really is positive)
• Negative Predictive Value (NPV): the probability that person is not infected when a negative result is observed (the chance that a negative result really is negative)

For a more detailed discussion of the statistics used to evaluate diagnostic test accuracy, go to http://www.rapid-diagnostics.org/accuracy.htm