Final answer:
Correct option is B. An increase in troponin levels is diagnostic of a myocardial infarction (MI), as it indicates heart muscle damage and is one of the most specific indicators for an MI.
Step-by-step explanation:
The nurse should recognize that an increase in troponin levels is diagnostic of a myocardial infarction (MI). Troponin is a regulatory protein for muscle contraction, and it is released into the bloodstream when the heart muscle has been damaged. Elevated troponin levels are one of the most specific blood test indicators for an MI, and they can remain elevated for several days after the event occurred.
Other tests, such as the electrocardiogram (ECG), may show alterations in the ST and Q components, which can indicate a STEMI (ST-elevated myocardial infarction) or a non-STEMI. While creatine kinase MB, white blood cell count, and blood glucose levels may also be affected, it is the troponin levels that provide the most conclusive evidence of an MI.