Question 1

Which one of the following is considered to be the most specific marker for adverse ventricular remodeling following an acute myocardial infarction?&#10;A) CK-2&#10;B) Troponin&#10;C) Myoglobin&#10;D) Brain natriuretic peptide (BNP)

Accepted Answer

Brain natriuretic peptide (BNP) is a hormone secreted by the ventricles in response to volume expansion and pressure overload, which are hallmarks of adverse ventricular remodeling. Elevated levels of BNP following an acute myocardial infarction have been shown to be strongly associated with adverse remodeling and poor outcomes. CK-2 and Troponin are markers of myocardial injury and Myoglobin is a marker of early myocardial injury, but they are not specific to adverse ventricular remodeling.

Question 2

In a point-of-care (POC)test for a cardiac biomarker used in the evaluation of an individual with possible acute coronary syndrome,which one of the following is a Laboratory Medicine Practice guideline of the National Academy of Clinical Biochemistry (NACB)?

A) POC testing must be performed with a maximum turnaround time of 24 hours.
B) POC assays should provide quantitative results.
C) Quality control and quality assurance are not required when using POC assays.
D) Laboratories that use qualitative POC biomarker assays should confirm results with a quantitative biomarker test.

Accepted Answer

POC assays should provide quantitative results to ensure accurate and reliable data for clinical decision-making in the evaluation of acute coronary syndrome.

Question 3

A 55-year-old man is taken to a hospital emergency department by helicopter following a rural automobile accident that occurred approximately 3 hours ago.The man,who is having difficulty speaking to the EMTs,is clutching his chest.Upon the man's arrival,the emergency room physician orders a cardiac marker panel that includes serum CK,CK-2 (CK-MB),troponin,and myoglobin.The CK-2 value was less than 2% of total CK,which was slightly increased; troponin was normal; and the myoglobin was increased 3 times the upper limit of normal.The physician has asked the laboratory to explain the findings.Which of the following represents the lab's explanation?

A) The assays used to determine these results were nonspecific and not sensitive enough to detect the troponin.
B) Trauma caused by the accident with possible crush injury to the chest caused elevated myoglobin with normal troponin and CK-MB.
C) The use of serum as a specimen interfered with troponin and CK-MB immunoassays giving falsely low results.
D) It is expected that in someone who has had a myocardial infarction in the past that all cardiac biomarker values except myoglobin to have returned to normal.

Accepted Answer

The elevated myoglobin suggests muscle damage, which could be due to chest trauma from the automobile accident. The normal troponin and CK-MB values suggest that there was not significant damage to the heart muscle.

Question 4

What are the laboratory results for CK-MB and cardiac troponin in the following conditions: muscular dystrophy,polymyositis,and extreme physical activity?&#10;A) CK-MB elevated,troponin normal&#10;B) CK-MB elevated,troponin elevated&#10;C) CK-MB normal,troponin elevated&#10;D) CK-MB normal,troponin normal

Accepted Answer

CK-MB is primarily found in the heart, but it can also be elevated in conditions involving muscle damage, such as muscular dystrophy and polymyositis, as well as after extreme physical activity. Cardiac troponin, however, is more specific to heart muscle damage and would typically remain normal in these conditions unless there is concurrent heart damage.

Question 5

Regarding assessment of congestive heart failure,NT-proBNP can be measured.This protein is:&#10;A) the C-terminal portion of the prepro-hormone natriuretic peptide (BNP).&#10;B) the N-terminal fragment of pro-BNP.&#10;C) an isoenzyme that migrates separately from BNP on an electrophoresis.&#10;D) degraded by circulating proteases to form the final form of BNP.

Accepted Answer

NT-proBNP is the N-terminal fragment of pro-BNP, which is the inactive precursor of the hormone BNP. When the heart muscle is stretched due to increased blood volume or pressure, pro-BNP is converted to BNP and NT-proBNP, which are released into the bloodstream. Measurement of NT-proBNP levels can be used as a diagnostic tool for congestive heart failure as it correlates with the severity of the condition.

Question 6

Which one of the following cardiac markers is elevated for the longest period of time after a myocardial infarction?&#10;A) Troponins&#10;B) hs-CRP&#10;C) CK-2 (CK-MB)&#10;D) Myoglobin

Accepted Answer

Troponins are elevated for the longest period of time after a myocardial infarction (MI), usually detectable for up to 10-14 days. CK-2 (CK-MB) is detectable for up to 48-72 hours and myoglobin for up to 24-36 hours. hs-CRP is not a cardiac marker but a marker of inflammation and can be elevated in various conditions, including MI. However, it does not have a specific time frame for elevation after an MI.

Question 7

Why would high-sensitivity C-reactive protein (CRP)be an indicator of a potential myocardial infarction?&#10;A) It is an acute phase reactant plasma protein that rises in response to inflammation and the atherosclerotic process.&#10;B) CRP levels rise in response to decreased ATP generation in the heart.&#10;C) It is a myocardial protein that regulates muscle contraction through interaction with myosin and actin.&#10;D) It is an enzyme found in skeletal muscle and cardiac muscle that is released upon muscle damage.

Accepted Answer

High-sensitivity C-reactive protein is an acute phase reactant protein that is produced by the liver in response to inflammation. Inflammation plays a significant role in the development and progression of atherosclerosis, which is a major risk factor for myocardial infarction. As such, elevations in CRP levels are thought to reflect underlying inflammation and atherosclerosis, and are therefore considered an indicator of a potential myocardial infarction. The other choices are not accurate explanations for the role of CRP in myocardial infarction.

Question 8

Laboratory measurements for brain natriuretic peptide (BNP)be reported in:&#10;A) millimoles/liter.&#10;B) grams/deciliter.&#10;C) nanograms/liter.&#10;D) picomoles/milliliter.

Accepted Answer

BNP is typically reported in nanograms per liter (ng/L). The other units listed (millimoles/L, grams/dL, and picomoles/mL) are not typically used for BNP measurement.

Question 9

Which one of the following cardiac biomarkers is elevated about 50 times the upper limit of normal at 24 hours after onset of an acute myocardial infarction?&#10;A) Total CK&#10;B) CK-2 (CKMB)&#10;C) Myoglobin&#10;D) Troponin

Accepted Answer

Troponin is the most specific biomarker for myocardial injury, with levels elevated about 50 times the upper limit of normal at 24 hours after onset of an acute myocardial infarction. Total CK and CK-2 (CKMB) are also elevated in the setting of myocardial injury, but not to the same extent as troponin. Myoglobin is an early and sensitive biomarker for myocardial injury, but its elevation is short-lived and not as specific as troponin.

Question 10

A cardiac marker that increases progressively with increasing severity of disease and is not increased (or decreased)in conditions that mimic congestive heart failure is:&#10;A) troponin I.&#10;B) CK-2.&#10;C) B-type natriuretic peptide.&#10;D) myoglobin.

Accepted Answer

B-type natriuretic peptide (BNP) is a cardiac marker that increases progressively with increasing severity of heart failure, and is not increased in conditions that mimic congestive heart failure. Troponin I and myoglobin are markers of cardiac injury, but may be elevated in non-ischemic conditions such as skeletal muscle injury. CK-2 is not a commonly used cardiac marker.

Question 11

In regard to cardiac anatomy,the myocardium:&#10;A) is the outermost layer of the cardiac wall.&#10;B) is composed of two upper chambers,the right and left atria.&#10;C) contains bundles of striated muscle fibers.&#10;D) is the sac that encloses the heart.

Accepted Answer

The answer of In regard to cardiac anatomy,the myocardium:&#10;A) is...

Question 12

The most common laboratory method used to assess brain natriuretic peptides is:&#10;A) HPLC.&#10;B) serum electrophoresis.&#10;C) nephelometry.&#10;D) immunoassay.

Accepted Answer

The answer of The most common laboratory method used to...

Question 13

Which one of the following troponins appears as uncomplexed or free following myocardial injury?&#10;A) Cardiac troponin I&#10;B) Cardiac troponin T&#10;C) Cardiac troponin C&#10;D) Ternary complex of T-I-C

Accepted Answer

The answer of Which one of the following troponins appears...

Question 14

The protein in cardiac muscle fibers that regulates contraction is:&#10;A) actin.&#10;B) myosin.&#10;C) B-type natriuretic peptide.&#10;D) troponin.

Accepted Answer

The answer of The protein in cardiac muscle fibers that...

Question 15

Which one of the following specimen types and collection methods is best for laboratory assessment of brain natriuretic peptide (BNP)in the evaluation of congestive heart failure?&#10;A) Serum in glass blood collection tubes only&#10;B) EDTA-anticoagulated whole blood or plasma in plastic blood collection tubes only&#10;C) Heparinized plasma in any type of blood collection tube&#10;D) Urine in sterile collection container for analysis of BNP metabolites only

Accepted Answer

The answer of Which one of the following specimen types...

Question 16

An ideal cardiac marker should be elevated in the circulation for how long following a cardiac event?&#10;A) At least several days&#10;B) 1 to 2 months&#10;C) 1 to 3 hours&#10;D) 1 to 3 years

Accepted Answer

The answer of An ideal cardiac marker should be elevated...

Question 17

In the process of atherosclerotic plaque formation,what is the typical precipitating event?&#10;A) Increased concentration of circulating coagulation factors&#10;B) Cellular involvement and clot formation&#10;C) Damage to the endothelium of cardiac blood vessels&#10;D) Release of tissue factor leading to coagulability

Accepted Answer

The answer of In the process of atherosclerotic plaque formation,what...

Question 18

MATCHING&#10;For each of the cardiac biomarkers,match the biochemical classification.&#10;Protein involved in muscle fiber contraction&#10;A)BNP&#10;B)CK-MB&#10;C)Troponin&#10;D)Myoglobin

Accepted Answer

The answer of MATCHING&#10;For each of the cardiac biomarkers,match the...

Question 19

In your clinical chemistry laboratory,you use an immunoassay to detect blood levels of NT-proBNP.You receive a filled green-top anticoagulant-containing plastic blood collection tube with a request for NT-proBNP.What is your next step?

A) Because this is an incorrect specimen type,contact the physician/nurse immediately and request a serum specimen.
B) Proceed,because this tube contains heparin and provides plasma after centrifugation,which is acceptable for the NT-proBNP assay.
C) Proceed,because this tube will provide serum after centrifugation,which is acceptable for the NT-proBNP assay.
D) Because only whole blood is acceptable,go ahead and run the test on the green-top tube.

Accepted Answer

The answer of In your clinical chemistry laboratory,you use an...

Question 20

Chest pain that is associated with a decrease in oxygen supply to the heart muscle but that exhibits no cellular necrosis based on cardiac troponin value and is considered a less severe event is referred to as:

A) angina.
B) acute myocardial infarction.
C) congestive heart failure.
D) thrombolysis.

Accepted Answer

The answer of Chest pain that is associated with a...

Question 21

MATCHING&#10;For each of the cardiac biomarkers,match the biochemical classification.&#10;Protein hormone&#10;A)BNP&#10;B)CK-MB&#10;C)Troponin&#10;D)Myoglobin

Accepted Answer

The answer of MATCHING&#10;For each of the cardiac biomarkers,match the...

Question 22

MATCHING&#10;For each of the cardiac biomarkers,match the biochemical classification.&#10;Oxygen-binding protein&#10;A)BNP&#10;B)CK-MB&#10;C)Troponin&#10;D)Myoglobin

Accepted Answer

The answer of MATCHING&#10;For each of the cardiac biomarkers,match the...

Question 23

MATCHING&#10;For each of the cardiac biomarkers,match the biochemical classification.&#10;Enzyme isoform&#10;A)BNP&#10;B)CK-MB&#10;C)Troponin&#10;D)Myoglobin

Accepted Answer

The answer of MATCHING&#10;For each of the cardiac biomarkers,match the...

Deck 34: Cardiovascular Disease