How is reliability defined in laboratory testing terms?

• A. Ability to distinguish between individuals
• B. Agreement between two tests
• C. Reproducibility across laboratories
• D. Precision across repeated measures

Answer: (A)

Reliability in laboratory testing means the results are repeatable and consistent. The most direct way to capture this is precision across repeated measures: if you run the same test on the same sample under the same conditions multiple times, you should get very similar results, indicating low random error.

Other aspects like reproducibility across laboratories and agreement between two tests are related facets of reliability, showing that results are consistent across different settings or methods. However, they are broader extensions of reliability rather than the core definition. Distinguishing between individuals reflects validity or discriminative ability, not reliability.