Question

A screening test for a newly discovered disease is being evaluated for its performance as a screening test. In order to determine the effectiveness of the new test, it was administered to 270 workers. A total of 42 individuals who had been diagnosed with the disease tested positive for it. Results showed a negative test for an additional 25 people with the disease. A total of 51 people without the disease tested positive. What is the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the test

Answer 1

- Sensitivity = 62.7 %

- specificity = 74.9 %

- positive predictive value = 45.2 %

- negative predictive value = 85.9 %

- Accuracy of the test = 71.9 %

Explanation:

Given the data in th question;

CONDITION POSITIVE CONDITION NEGATIVE TOTAL

TEST POSITIVE 42 51 93

TEST NEGATIVE 25 152 177

TOTAL 67 203 270

so; A=42, B=51, C=25 and D=152

Sensitivity = [A / ( A + C) ]×100= [42 /( 42 + 25)]×100 = [42 / 67] 100=

Sensitivity = 62.7 %

specificity = [D / ( D + B) ]×100= [152 /( 152 + 51)]×100 = [152 / 203] 100=

specificity = 74.9 %

positive predictive value = [A / ( A + B) ]×100 = [42 /( 42 + 51)]×100 =[42/93] 100

positive predictive value = 45.2 %

negative predictive value = [D / ( D + C) ]×100 = [152 /( 152 + 25)]×100 =[152/177] 100

negative predictive value = 85.9 %

Accuracy of the test = [A + D / ( A+B+C+D)] = [42 + 152 / ( 42+51+25+152)]

= [ 194 / 270 ]

Accuracy of the test = 71.9 %