Question

A new tumour marker for ovarian cancer is evaluated for sensitivity by testing serum samples from patients who have been diagnosed by staging biopsy as having malignant or benign lesions. The following results were obtained:

             Number of malignant patients who are positive for ovarian cancer = 21 out of 24

             Number of benign patients who are negative for ovarian cancer = 61 out of 62

a. What is the sensitivity of the new ovarian cancer test?

b. What is the specificity of benign patients for the ovarian cancer?

c. How would you interpret these results to a layman?  

A new tumour marker for ovarian cancer is evaluated for sensitivity by testing serum samples from patients who have been diagnosed by staging biopsy as having malignant or benign lesions. The following results were obtained:

             Number of malignant patients who are positive for ovarian cancer = 21 out of 24

             Number of benign patients who are negative for ovarian cancer = 61 out of 62

a. What is the sensitivity of the new ovarian cancer test?

b. What is the specificity of benign patients for the ovarian cancer?

c. How would you interpret these results to a layman?  

Answer 1

ANSWER:-

a.

Sensitivity =( number of patients true positive / total number of person) ×100 = (21/24) ×100 = 0.875 ×100 = 87.5 % .

b.

Specificity =( number of true negative person/ total number of person) ×100= (61/62 ) ×100 = 98.34%.

c.

SENSITIVITY, means the amount of true positive cases the test can identify . Here sensitivity is 87.5% means that 87.5 % of the total people in this test have the disease ( malignant ovarian cancer). And also the test

Has a ( 100 -87.5)= 12.5 % of false negative result means the test can not detect the 12.5% of the people who have the disease but the test showing negative.

As the tumour marker can detect 87.5% of malignant cancer so it is quite good marker and useful.

SPECIFICITY,  amount of true negative results the test can detect. Here specificity is 98.34% means the tumour marker can detect 98.34% of true  negative benign patient which says that 98.34% of the patients not have the benign tumour and which is also correct.

According to the test results, the tumour marker is to much helpful and valuable as it's showing impressive , sensitivity and specificity .