If biochemical test gives the same reading of r given sample on repeated testing, it is inferred that the measurement is –
**Core Concept**
The question pertains to the concept of analytical reliability in biochemical testing, specifically the principle of precision. Precision refers to the closeness of replicate measurements when the measurement procedure is applied multiple times under the same conditions.
**Why the Correct Answer is Right**
When a biochemical test yields the same result on repeated testing of the same sample, it is inferred that the measurement is precise. This is because precision is a measure of the consistency or reproducibility of the results obtained from multiple analyses of the same sample under the same conditions. In this context, the test is said to be precise if the results are consistent and not variable. This is often quantified using the coefficient of variation (CV), which is a measure of the ratio of the standard deviation to the mean.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because accuracy refers to the closeness of a measured value to the true value. Precision does not necessarily imply accuracy.
* **Option B:** This option is incorrect because stability refers to the ability of a test to maintain its performance over time. While stability is an important aspect of test quality, it is not directly related to the concept of precision.
* **Option C:** This option is incorrect because specificity refers to the ability of a test to detect only the target analyte. Precision is a measure of the consistency of the results, not the ability to detect the correct analyte.
**Clinical Pearl / High-Yield Fact**
A key concept to remember is that precision and accuracy are two distinct aspects of test quality. While a precise test may be accurate, a precise test may not necessarily be accurate if the results are consistently biased.
**Correct Answer:** D.