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Why are enzyme levels in blood tested after damage to the heart or liver?

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blood analysis The physical and chemical properties of a sample of blood are examined during blood analysis. The examination of blood is important for the accurate diagnosis of disease.

Enzyme levels in the blood are tested after heart or liver damage because these organs contain high concentrations of specific enzymes that perform vital catalytic functions within their cells. Under normal conditions, these enzymes remain inside the cells and tissues.1

However, when cells in the heart or liver are injured or undergo necrosis—such as during a myocardial infarction or liver disorders like hepatitis—the damaged cell membranes become permeable. This allows the enzymes to leak out of the injured tissue and into the blood serum.12

By measuring the activity of these specific enzymes in a blood sample, clinicians can identify and assess the extent of tissue damage. For example, transaminases are found in particularly high concentrations in heart and liver tissue, and their elevated presence in the blood serves as a diagnostic indicator of injury to those organs.1