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

a=true

positives

b=false

positives

c=false

negatives

d=true

negatives

Test

result

POS

NEG

total

a+b

c+d

TOT

a+c

b+d

Sensitivity = a/ (a+c)

Specificity = d/ (b+d)

PV+ = a/ (a+b)

PV- = d/ (c+d)