August 30, 2016 SPADA Meeting Book

Clinical Diagnostic Performance Related to Disease Prevalence: 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

Clinical Diagnostic Performance Related to Disease  Prevalence: Test Parameters

Disease

present

absent

total

a=true positives

b=false positives

POS

a+b

PV+ = a/ (a+b) PV- = d/ (c+d)

Test result

c=false negatives

d=true

NEG

c+d

negatives

TOT

a+c

b+d

Sensitivity = a/ (a+c) Specificity = d/ (b+d)