Which of the following is NOT a feature of an ideal cardiac marker?

• A. Ability to predict future occurrence of cardiac disease
• B. Absolute specificity
• C. High sensitivity
• D. Close estimation of the magnitude of cardiac damage

Answer: (B)

A marker for heart damage should reliably indicate myocardial injury and be as specific to the heart as possible, while also providing information about how large the injury is and, ideally, help gauge future risk. It’s okay for a marker to be highly specific, but in practice no test is absolutely specific. There will always be some situations where non-cardiac factors, assay interference, or other conditions can cause elevations or false positives. That’s why an “absolute specificity” feature isn’t achievable, even though we strive for very high specificity. The other features—detecting injury with high sensitivity, estimating the magnitude of damage, and offering prognostic information—are consistent with what an ideal cardiac marker aims to provide.