Patho Patho #28

Question

The client in the emergency department with chest pain. Which laboratory test is done to determine a diagnosis of myocardial infarction?

Answers

  1. Serum potassium
    • Rationale:

      This answer choice is not correct because serum potassium is not drawn to confirm a diagnosis of myocardial infarction.

  2. Homocysteine
    • Rationale:

      This answer choice is not correct because homocysteine levels are not drawn to confirm a diagnosis of myocardial infarction. Homocysteine is an amino acid commonly found in the blood.

  3. Troponin I
    • Rationale:

      This answer is correct because Troponin I is the most sensitive indicator of the diagnosis of myocardial infarction. Troponin I is a hormone that is released by necrotic myocardial cells. A Troponin I level greater than 0.40 ng/dL is indicative of myocardial damage.

  4. Highly sensitive C-reactive protein
    • Rationale:

      This answer choice is not correct because C-reactive protein is an indicator of the presence of inflammation within the body and is not sensitive to myocardial damage.

Overview

The focus of this question is asking the nurse to determine the most sensitive laboratory test to confirm a diagnosis of myocardial infarction. When signs and symptoms of myocardial infarction are present, further evaluation in the form of a 12 lead ECG and a ROMI (rule out myocardial infarction) panel is indicated. The ROMI panel consists of a series of Troponin I levels, which if elevated, is indicative of myocardial infarction.

Explanation

Learning Outcomes

When a client presents to the emergency department with reports of chest pain, the client requires further evaluation for myocardial infarction. In addition to a focused cardiac assessment, a 12 lead ECG will be performed and Troponin I levels will be drawn. Troponins are drawn at the onset of symptoms, then at the 3 hour, 6 hour, and 12 hour intervals. A consistent increase in Troponin I in addition to ECG changes is indicative of myocardial infarction.

Test Taking Tip

Be sure to review the most relevant lab values pertaining to disease processes. You will most likely not be tested over lab values that are rarely used to diagnose conditions or are not disease specific. For example, Troponin is the most important lab value in the setting of possible myocardial infarction. BNP is the most important lab value in the setting of heart failure.

Video Rationale