Table 2.

Characteristics of assay analytical performance and statistical analyses for evaluating test(s) accuracy

Characteristics
Specimen and analytical performance characteristics
• Specimen stability with freeze/thaw
• Specimen type and matrix complexity (undiluted plasma/serum may have circulating antibodies that can cross-react with the specific antibodies)
• Assay specificity (interference, cross-reactivity)
• Assay sensitivity (lower limit of detection)
• Assay range
• Precision within runs and between runs
• Accuracy: Recovery of spiked analyte is within 75%-125% at all ranges
Analysis for test(s) accuracy evaluation
• Sensitivity: Proportion of subjects in a sample of patients with the target condition in whom the test is positive
• Specificity: Proportion of subjects in a sample of patients without the target condition in whom the test is negative
• Receiver operator characteristic curve: A plot of the true-positive rate vs the false-positive rate for all possible cut points of a biomarker
• Positive predictive value: Proportion of patients in the overall population with a positive test who have the target condition
• Negative predictive value: Proportion of patients in the overall population with a negative test who do not have the target condition