Biochemical Cardiac Markers

New cardiac markers are frequently being developed, so we need to know how to interpret their evaluation. Cardiac markers are typically evaluated by a diagnostic cohort study in which the new marker is compared to a reference standard, such as AMI, defined by recognised criteria.

The results of these studies often focus upon sensitivity or negative predictive value to demonstrate the value of the marker (or panel of markers) for ruling out AMI, but this only tells half the story.

A new cardiac marker has 100% sensitivity and 100% negative predictive value for AMI. Will it be diagnostically useful?

• Sensitivity – the proportion of subjects who have the condition and test positive for it
• Specificity – the proportion of subjects who do not have the condition and test negative for it
• Negative Predictive Value – the probability that a subject with a negative test result does not have the disease
• Positive Predictive Value – the probability that a subject with a positive test result has the condition