Diagnostic and/or screening tests are designed to separate persons without disease from individuals with disease based on a biological variable. Which example illustrates this?

• A. A test that predicts future risk of heart disease
• B. A test that separates diseased from non-diseased
• C. A test that measures general fitness
• D. A test that assesses mood status

Answer: (B)

Diagnostic and screening tests are used to classify people by their current disease status—whether the disease is present or not—based on a biological indicator. The best example here is a test that separates diseased from non-diseased, because it directly tags individuals as having or not having the disease using a biological variable.

A test that predicts future risk looks at who might develop disease later, not who has it now, so it’s about prognosis rather than current status. A test that measures general fitness or mood status assesses other health attributes that aren’t about identifying whether a disease is present.