The nurse is caring for client who presented to the emergency department for chest pain. The nurse knows that which of the following laboratory tests is most specific for myocardial damage?
Troponins I & T
Creatine Kinase
C Reactive Protein
Myoglobin
The Correct Answer is A
A. Troponins I & T:
Troponins I and T are the most specific biomarkers for myocardial damage. These proteins are released into the bloodstream when the heart muscle is injured, such as during a myocardial infarction (MI). Troponins remain elevated for a prolonged period (typically up to 1-2 weeks) after myocardial injury, making them highly sensitive for detecting both acute and recent myocardial damage. Because of their high specificity for heart muscle, they are considered the gold standard for diagnosing acute myocardial infarction.
B. Creatine Kinase:
Creatine kinase (CK) is an enzyme found in the heart, brain, and skeletal muscle. While CK-MB (the heart-specific isoenzyme) can be elevated in cases of myocardial damage, it is less specific than troponins because it can also be elevated due to skeletal muscle injury or other conditions. CK-MB levels rise more rapidly than troponins but return to baseline within 48-72 hours, making it less useful for detecting myocardial damage over a longer period.
C. C-Reactive Protein (CRP):
C-Reactive Protein (CRP) is an acute-phase reactant produced by the liver in response to inflammation or tissue injury. While CRP levels can be elevated in various inflammatory conditions, including atherosclerosis, it is not specific to myocardial damage. Elevated CRP is associated with increased risk for cardiovascular events but does not provide specific information about acute myocardial injury, making it less helpful for diagnosing myocardial infarction.
D. Myoglobin:
Myoglobin is an oxygen-binding protein found in both skeletal and cardiac muscle. While it is an early marker that rises rapidly after muscle injury, it lacks specificity for myocardial damage because it is also released from skeletal muscle. Myoglobin levels peak quickly (within 1-4 hours of injury) and return to baseline within 24 hours, so it is not as useful for diagnosing a myocardial infarction or monitoring long-term cardiac injury.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A) Simvastatin: Simvastatin is a medication used to lower cholesterol levels and does not typically require monitoring of blood pressure before or after administration. While statins may have some indirect cardiovascular benefits, blood pressure is not directly affected by this medication, so it is not necessary to assess blood pressure before or after administering simvastatin.
B) Metoprolol: This is the correct answer. Metoprolol is a beta-blocker commonly used to treat hypertension and other cardiovascular conditions. It works by reducing heart rate and blood pressure. Therefore, it is important to assess the client's blood pressure both before and after administering metoprolol to ensure the medication is having the desired effect and to detect any adverse changes, such as hypotension or bradycardia.
C) Acetylsalicylic Acid (Aspirin): Aspirin is primarily used for its antiplatelet effect, such as for preventing heart attacks or strokes, and it does not have a significant direct impact on blood pressure. While aspirin can have side effects, such as gastrointestinal irritation or bleeding, blood pressure monitoring is generally not necessary before or after administering aspirin.
D) Metformin: Metformin is used to manage type 2 diabetes by helping control blood glucose levels. It does not directly affect blood pressure, so routine blood pressure assessment is not required before or after giving metformin. However, monitoring for side effects like gastrointestinal distress or lactic acidosis is important, but blood pressure is not a priority for this medication.
Correct Answer is B
Explanation
A) Fasting plasma glucose of 98 mg/dl:
A fasting plasma glucose level of 98 mg/dl is within the normal range (70–99 mg/dl). According to diagnostic criteria, a fasting plasma glucose level of 100–125 mg/dl is considered prediabetes, and 126 mg/dl or higher on two separate occasions is diagnostic for diabetes. Therefore, a fasting plasma glucose of 98 mg/dl is not diagnostic for diabetes.
B) Hemoglobin A1C (glycosylated hemoglobin) of 7.2%:
An HbA1C level of 7.2% is diagnostic for diabetes. The American Diabetes Association (ADA) defines diabetes as an HbA1C of 6.5% or higher. The HbA1C test reflects the average blood glucose level over the past 2–3 months, and a level of 7.2% indicates that the patient's blood glucose levels have been elevated over time, consistent with diabetes. This is a key diagnostic criterion.
C) Random plasma glucose of 110 mg/dl:
Although a random glucose value greater than 200 mg/dl with symptoms of hyperglycemia can be diagnostic of diabetes, 110 mg/dl is within the normal range and does not meet the criteria for a diabetes diagnosis. For diagnostic purposes, a random plasma glucose must be 200 mg/dl or higher.
D) Two hour plasma glucose of 140 mg/dl:
For the test to be diagnostic of diabetes, the plasma glucose must be 200 mg/dl or higher after two hours. A level of 140 mg/dl suggests normal glucose tolerance or prediabetes, but it is not diagnostic for diabetes.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.