SPADA
Test parameters
• Sensitivity: – the ability to identify as positive all those with the disease • Specificity: – the ability to identify as negative all those without the disease • Predictive value positive (PV+): – the proportion of true positives among those testing positive • Predictive value negative (PV-): – the proportion of true negatives among those testing negative
Disease
present
absent
PV+ = a/ (a+b)
total
PV- = d/ (c+d)
a=true positives
b=false positives
Test result
POS
a+b
d=true negatives
c=false negatives
NEG
c+d
TOT
a+c
b+d
Sensitivity = a/ (a+c)
Specificity = d/ (b+d)
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