Question
The table below shows the results of an Enzyme-Linked Immunosorbent Assay (ELISA) test for Human Immunodeficiency Virus (HIV) infection.
| True Infection Status |
Positive |
Negative |
Total |
| Infected |
4900 |
100 |
5000 |
| Non-infected |
950 |
94050 |
95000 |
| Total |
5850 |
94150 |
100000 |
Consider the following statements:
- The sensitivity is 98%.
- The specificity is 99%.
Which of the statements given above is/are correct?
| A. |
1 only
|
| B. |
2 only
|
| C. |
Both 1 and 2
|
| D. |
Neither 1 nor 2
|
Show Answer
|
Correct Answer » C
Explanation
|
|
To calculate the validity of a diagnostic test, identify the following:
- True Positive (TP) = 4900
- False Negative (FN) = 100
- False Positive (FP) = 950
- True Negative (TN) = 94050
Statement 1: Sensitivity
Sensitivity is the ability of a test to correctly identify individuals who have the disease.
Formula:
Sensitivity = TP / (TP + FN) × 100
Calculation:
= 4900 / (4900 + 100) × 100
= 4900 / 5000 × 100
= 98%
Therefore, Statement 1 is correct.
Statement 2: Specificity
Specificity is the ability of a test to correctly identify individuals who do not have the disease.
Formula:
Specificity = TN / (TN + FP) × 100
Calculation:
= 94050 / (94050 + 950) × 100
= 94050 / 95000 × 100
= 99%
Therefore, Statement 2 is also correct.
Hence, both statements are correct.
