Question

A screening test wished to improve the diagnostic ability to identify Zika-infected fetuses in pregnancy rather than after birth. A total of 330 pregnant women (carrying one baby each) in Miami were tested. A total of 36 babies had Zika; 24 of whom tested positive. A total of 300 babies tested negative for the virus. What is the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the test?
a. 94.5%
b. 33.3%
c. 66.7%
d. 96.0%
e. 98.0%
f. 80.0%

Answer 1

Answer:

Sensitivity = 66.7%  (C)

specificity= 98.0%  (E)

positive predictive value = 80.0%  (F)

Negative predictive value = 96.0%  (D)

accuracy of the test  = 94.5%  (A)

Step-by-step explanation:

Given the data in the question;

                                    Disease Present              Disease Absent        Total

Test Positive                      24                                        6                        30

Test Negative                    12                                       288                     300

Total                                   36                                       294                    330

so A = 24, B = 6, C = 12 and D = 288

sensitivity = [A/(A+C)]×100 = [24/(24+12)]×100 = [24/36]×100

Sensitivity = 66.7%  (C)

specificity= [D/(D+B)]×100 = [288/(288+6)]×100 = [288/294]×100

specificity= 98.0%  (E)

positive predictive value = [A/(A+B)]×100 = [24/(24+6)]×100

= [24/30]×100

positive predictive value = 80.0%  (F)

Negative predictive value = [D/(D+C)]×100 = [288/(288+12)]×100

= [288/300]×100

Negative predictive value = 96.0%  (D)

accuracy of the test = [A+D/(A+B+C+D)]×100 = [24+288/(24+6+12+288)]×100

= [312/330]×100

accuracy of the test  = 94.5%  (A)

Nothing 33.3% (B)