Which test measures specific proteins in the blood that rise after heart injury?

• A. CK-MB
• B. Lipase
• C. ESR
• D. Troponin test

Answer: (D)

Proteins released into the blood after heart muscle is damaged serve as highly specific indicators of cardiac injury. The troponin test measures cardiac-specific regulatory proteins, troponin I and troponin T, which leak into the bloodstream when heart muscle cells are damaged. Because these troponins are unique to cardiac tissue, their presence in the blood provides a precise signal of myocardial injury and helps confirm conditions like myocardial infarction, as well as gauge severity.

Other options don’t fit as well. CK-MB increases after heart injury too, but it isn’t as specific because it is also found in skeletal muscle, making it less reliable for identifying heart-only damage. Lipase is a marker for pancreatic inflammation, not cardiac injury. ESR is a broad inflammation marker and doesn’t specifically indicate heart muscle damage. Troponin testing is preferred due to its high sensitivity and specificity, and its levels remain elevated long enough to catch injuries that aren’t immediately evident.