Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Complete absence of false negative results would make a diagnostic kit highly successful.
Reason R: False negatives are due to poor sensitivity of the phenotypic or molecular marker deployed.

In light of the above statements, choose the correct answer from the options given below:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

Remember this relationship:
- High Sensitivity = Few or No False Negatives.
- High Specificity = Few or No False Positives.
- Sensitivity measures the limit of detection.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Diagnostic kits used in agriculture and medicine must be evaluated on sensitivity and specificity.
Sensitivity refers to the ability of a test to correctly identify positive samples (true positive rate), minimizing false negatives.
Specificity refers to the ability to correctly identify negative samples (true negative rate), minimizing false positives.
Detailed Explanation:
Let us analyze both Assertion and Reason:
Assertion A:
A highly successful diagnostic kit is one that does not miss any positive cases.
The complete absence of false negatives means that whenever a pathogen is present, the kit successfully detects it (100% sensitivity).
Thus, Assertion A is true.
Reason R:
False negatives occur when a kit indicates a sample is healthy when it is actually infected.
This failure is directly linked to the low sensitivity of the marker (molecular, serological, or phenotypic) being used, which fails to detect low titers of the pathogen.
Thus, Reason R is true.
Analyzing the connection:
Because false negatives are caused by low sensitivity (Reason R), achieving a zero false-negative rate (100% sensitivity) is the primary determinant of a kit's performance and reliability.
Therefore, Reason R directly explains why preventing false negatives makes the kit successful.

Step 2: Final Answer:
Both Assertion A and Reason R are true, and R is the correct explanation of A.
Hence, the correct option is (A).