CC2 LEC (P) L6: CK

aint in la adela

A

What specific chemical reaction is catalyzed by Creatine Kinase (CK)?

a. The transfer of phosphate to creatine.

b. The reversible conversion of lactate and NAD into pyruvate.

c. The hydrolysis of phosphomonoesters into alcohol and phosphate.

d. The transfer of the gamma glutamyl from gamma glutamyl peptides.

A

Which substances are required as a co-factor and a source for the activation of Creatine Kinase?

a. Magnesium and a thiol source (cysteine).

b. Calcium and chloride.

c. Zinc and manganese.

d. Iron and copper.

A

Which elements are known to inhibit Creatine Kinase activity, especially when present in excess?

a. Zinc and manganese.

b. Calcium and chloride.

c. Iron and copper.

d. Sodium and potassium.

A

What is the product formed from creatine by the action of Creatine Kinase that can be used as a source of energy?

a. Phosphocreatine.

b. Pyruvate.

c. 2-monoglyceride.

d. Maltopentose.

A

Which Creatine Kinase isoenzyme is recognized as the "brain type"?

a. CK-BB / CK-1.

b. CK-MB / CK-2.

c. CK-MM / CK-3.

d. Macro-CK type 1.

A

Which Creatine Kinase isoenzyme is recognized as a marker for the heart in healthy individuals and is known as the "hybrid type"?

a. CK-MB / CK-2.

b. CK-BB / CK-1.

c. CK-MM / CK-3.

d. Mitochondrial CK.

A

Which Creatine Kinase isoenzyme is the predominant form found in skeletal muscle?

a. CK-MM / CK-3.

b. CK-MB / CK-2.

c. CK-BB / CK-1.

d. Macro-CK type 2.

A

What percentage of total Creatine Kinase activity in normal serum is derived from the CK-MM isoenzyme?

a. 95% of total CK activity.

b. 5% of total CK activity.

c. 50% of total CK activity.

d. 100% of total CK activity.

A

What is the approximate half-life of the CK-BB isoenzyme in circulation?

a. 2-3 hours.

b. 12 hours.

c. 15 hours.

d. 48 hours.

A

What is the approximate half-life of the CK-MB isoenzyme in circulation?

a. 12 hours.

b. 2-3 hours.

c. 15 hours.

d. 72 hours.

A

What is the approximate half-life of the CK-MM isoenzyme in circulation?

a. 15 hours.

b. 2-3 hours.

c. 12 hours.

d. 24 hours.

A

Under what specific condition does Mitochondrial CK appear in the circulation?

a. When more severe cellular damage (massive tissue destruction) takes place.

b. Following minor muscular exercise.

c. During normal healthy states.

d. Following a fatty meal.

A

Which statement accurately describes the electrophoretic mobility of Creatine Kinase isoenzymes from most cathodal to most anodal?

a. CK-mitochondria -> CK-MM/3 -> CK-MB/2 -> CK-BB/1.

b. CK-BB/1 -> CK-MB/2 -> CK-MM/3 -> CK-mitochondria.

c. CK-MM/3 -> CK-BB/1 -> CK-mitochondria -> CK-MB/2.

d. CK-MB/2 -> CK-mitochondria -> CK-BB/1 -> CK-MM/3.

A

During electrophoresis, where is the Macro-CK type 1 band typically located relative to the standard isoenzymes?

a. In between CK-MB and CK-MM.

b. Faster than CK-BB.

c. Slower than Mitochondrial CK.

d. Between CK-BB and CK-MB.

A

Following an Acute Myocardial Infarction (AMI), when does CK-MB typically begin to rise?

a. Rises after 4-8 hours.

b. Rises after 12-24 hours.

c. Rises after 1-2 hours.

d. Rises after 48 hours.

A

At what time point does CK-MB typically reach its peak concentration following an AMI?

a. Peaks at 12-24 hours.

b. Peaks at 4-8 hours.

c. Peaks at 48-72 hours.

d. Peaks at 96 hours.

A

When does CK-MB generally return to normal levels following an Acute Myocardial Infarction?

a. Returns to normal within 48 to 72 hours.

b. Returns to normal within 12-24 hours.

c. Returns to normal within 5 days up to 2 weeks.

d. Returns to normal within 10 days.

A

Which specific disease is known to produce the highest elevation of Creatine Kinase (increasing 100x in elevation)?

a. Duchenne's muscular dystrophy.

b. Acute Myocardial Infarction.

c. Polymyositis.

d. Dermatomyositis.

A

In which major organ is Creatine Kinase completely absent, making its absence useful for ruling out issues in this organ when evaluating CK levels?

a. LIVER.

b. Heart.

c. Brain.

d. Skeletal muscle.

A

Which of the following conditions is categorized as causing a "Pronounced Elevation" (5 or more times than Normal) of Creatine Kinase?

a. Polymyositis.

b. Severe exercise.

c. Hypothyroidism.

d. Pulmonary infarction.

A

Which muscular disorder, alongside Duchenne's and Polymyositis, causes a pronounced elevation of Creatine Kinase?

a. Dermatomyositis.

b. Delirium tremens.

c. Alcoholic myopathy.

d. Myasthenia gravis.

A

Which cardiac event causes a pronounced elevation (5 or more times than Normal) of Creatine Kinase?

a. Myocardial infarction.

b. Mild angina.

c. Pulmonary edema.

d. Benign palpitations.

A

Why must hemolysis specifically be avoided when collecting a sample for Creatine Kinase analysis, even though CK itself is not present in RBCs?

a. Adenylate kinase, which catalyzes a similar reaction as that of CK, is present in RBCs, causing a false increase.

b. Hemoglobin reacts with the sulfhydryl activator causing a false decrease.

c. RBCs contain large amounts of zinc which inhibits the reaction entirely.

d. Hemolysis drops the optimal pH required for the Oliver-Rosalki method.

A

What specific precaution must be taken regarding the storage environment for a Creatine Kinase specimen?

a. Stored in the dark since it has been found that CK is inactivated by light.

b. Stored under bright UV light to activate the isoenzymes.

c. Stored exclusively at 37°C indefinitely.

d. Stored in a vacuum to prevent oxidation

A

What is the reference range for Total CK in males at 37°C?

a. 46-171 U/L.

b. 34-145 U/L.

c. 125-220 U/L.

d. <5% total CK.

B

What is the reference range for Total CK in females at 37°C?

a. 46-171 U/L.

b. 34-145 U/L.

c. 5-38 U/L.

d. 30-220 U/L.

B

What is the expected reference proportion for the CK-MB isoenzyme relative to total CK?

a. >95% total CK.

b. <5% total CK.

c. 50% total CK.

d. >20% total CK.

B

Which type of chemical compound is required as an activator in the methodologies measuring Creatine Kinase?

a. A calcium-binding chelator.

b. A sulfhydryl activator (e.g., cysteine, N-acetyl cysteine, glutathione).

c. A strong oxidizing agent.

d. A copper salt complex.

B

Which of the following is listed as a specific sulfhydryl activator used in CK methodologies?

a. Phenazine methosulfate.

b. Dithiothreitol or Cleland's reagent.

c. p-nitrophenylhydrazine.

d. Wheat germ lectin.

B

The Tanzer-Gilvarg method measures which direction of the Creatine Kinase reaction?

a. The Reverse Reaction.

b. The Forward Reaction.

c. The continuous monitoring method.

d. The chromogenic reaction.

B

In the first step of the Tanzer-Gilvarg (Forward Reaction) method, what are the starting substrates?

a. Creatine phosphate and ADP.

b. Creatine and ATP.

c. Pyruvate and NADH.

d. Glucose and ATP.

B

What is the final coupled reaction measured in the Tanzer-Gilvarg method?

a. Conversion of Glucose 6-phosphate to 6-phosphogluconate.

b. Pyruvate + NADH + H+ -> Lactate + NAD+.

c. ADP + phosphoenolpyruvate -> Pyruvate + ATP.

d. Creatine + ATP -> Creatine phosphate + ADP.

B

What specific change in absorbance is measured in the Tanzer-Gilvarg method at 340 nm?

a. The increase in absorbance as NAD is reduced to NADH.

b. The decrease in absorbance as NADH is oxidized to NAD, because NADH absorbs light at 340 nm while NAD does not.

c. The appearance of a blue-purple color.

d. The appearance of a golden brown color.

B

What is the optimal pH maintained for the Tanzer-Gilvarg (Forward Reaction) method?

a. 6.8.

b. 9.0.

c. 7.4.

d. 10.15.

B

The Oliver-Rosalki method measures which direction of the Creatine Kinase reaction?

a. The Forward Reaction.

b. The Reverse Reaction.

c. The amyloclastic reaction.

d. The saccharogenic reaction.

B

How does the reaction rate of the Oliver-Rosalki method compare to the Tanzer-Gilvarg method?

a. It is 3x slower.

b. It is faster than the forward (2-6x).

c. It is identical in speed.

d. It takes 24 hours to complete.

B

Which of the two main methodologies for measuring Creatine Kinase is the most commonly performed method?

a. The Tanzer-Gilvarg method.

b. The Oliver-Rosalki method.

c. The Cherry and Crandall method.

d. The Bowers and Mc Comb method.

B

In the first step of the Oliver-Rosalki (Reverse Reaction) method, what are the starting substrates?

a. Creatine and ATP.

b. Creatine phosphate and ADP.

c. ATP and glucose.

d. Glucose 6-phosphate and NADP.

B

In the Oliver-Rosalki method, what is the ATP produced in the first step immediately used for?

a. To reduce pyruvate to lactate.

b. It is immediately used by hexokinase to phosphorylate glucose, producing glucose-6-phosphate (G-6-P).

c. To activate the sulfhydryl bonds in the enzyme.

d. To oxidize NADH back to NAD.

B

What is the final coupled reaction measured in the Oliver-Rosalki method?

a. Pyruvate + NADH + H+ -> Lactate + NAD+.

b. Glucose 6-phosphate + NADP -> 6-phosphogluconate + NADPH (via G-6-PD).

c. Creatine phosphate + ADP -> Creatine + ATP.

d. ATP + glucose -> ADP + glucose-6-phosphate.

B

What specific change in absorbance is measured in the Oliver-Rosalki method at 340 nm?

a. The decrease in absorbance as NADH is oxidized.

b. The increase in absorbance as NADP is reduced to NADPH, because NADPH absorbs light at 340 nm while NADP does not.

c. The change in color of p-Nitroaniline.

d. The precipitation of a fatty acid-copper complex.

B

What is the optimal pH maintained for the Oliver-Rosalki (Reverse Reaction) method?

a. 9.0.

b. 6.8.

c. 10.5.

d. 5.0.

B

Which of the following non-muscular conditions is listed as causing a "Mild or Moderate Elevation" (up to 5 times Normal) of Creatine Kinase?

a. Acute pancreatitis.

b. Hypothyroidism.

c. Mumps.

d. Viral hepatitis.

B

Which psychiatric condition is known to cause a mild or moderate elevation of Creatine Kinase?

a. Generalized anxiety disorder.

b. Acute agitated psychoses.

c. Major depressive disorder.

d. Obsessive-compulsive disorder.

B

Which of the following conditions involving alcohol consumption can cause a mild or moderate elevation in CK?

a. Uncomplicated acute intoxication.

b. Delirium tremens, alcoholic myopathy.

c. Alcoholic cirrhosis.

d. Alcoholic hepatitis.

B

Which of the following iatrogenic or physical causes can lead to a mild or moderate elevation of Creatine Kinase?

a. Venipuncture using a butterfly needle.

b. Severe exercise, trauma, surgical procedure, intramuscular injections.

c. Subcutaneous insulin administration.

d. Oral ingestion of opioid analgesics.

B

What is the relationship between Creatine Kinase (CK) isoenzymes and their structural composition?

a. They are tetramers composed of H and M subunits.

b. They are dimers composed of M (muscle) and B (brain) subunits.

c. They are monomers with no subunit distinction.

d. They are hexamers exclusively found in mitochondria.

B

On an electrophoresis gel, which Creatine Kinase band migrates the furthest toward the anode (+)?

a. CK-MB.

b. CK-BB.

c. CK-MM.

d. Mitochondrial CK.

B

On an electrophoresis gel, which Creatine Kinase band remains closest to the cathode (-)?

a. CK-MB.

b. CK-MM.

c. CK-BB.

d. Macro-CK type 1.

B

Based on the time course of elevation graph, how does the peak time of CK compare to AST and LD after a myocardial infarction?

a. CK peaks after AST and LD.

b. CK peaks before AST and LD.

c. All three enzymes peak simultaneously.

d. LD peaks first, followed by CK, then AST.

C

What happens to Creatine Kinase activity when a specimen is exposed to light?

a. It becomes hyperactive due to photo-activation.

b. It converts completely into the CK-BB isoenzyme.

c. CK is inactivated by light.

d. Light has no effect on Creatine Kinase stability.

C

In healthy individuals, which CK isoenzyme is almost entirely responsible for the total CK activity found in serum?

a. CK-BB.

b. CK-MB.

c. CK-MM.

d. Mitochondrial CK.

C

If a patient presents with a pronounced elevation of Creatine Kinase, but tests confirm the absence of myocardial infarction, what broad category of disease is most likely?

a. Hepatobiliary disease.

b. Pancreatic disease.

c. Muscle-related disease (e.g., Duchenne's, Polymyositis).

d. Renal disease.

C

Which enzyme present in red blood cells is the specific reason why hemolysis causes a false increase in Creatine Kinase assays?

a. Lactate dehydrogenase.

b. Acid phosphatase.

c. Adenylate kinase.

d. Gamma glutamyl transferase.

C

In the Oliver-Rosalki method, which enzyme is utilized to catalyze the reaction between glucose 6-phosphate and NADP?

a. Hexokinase.

b. Pyruvate kinase.

c. Glucose-6-phosphate dehydrogenase (G-6-PD).

d. Lactate dehydrogenase.

C

What is the specific role of N-acetyl cysteine or Cleland's reagent in the CK methodologies?

a. They act as the primary substrate.

b. They act as the chromogenic dye.

c. They serve as a sulfhydryl activator required for the reaction.

d. They act to precipitate out interfering adenylate kinase.

C

Which CK isoenzyme is specifically noted as being low in healthy individuals but seen in massive tissue destruction?

a. CK-MB.

b. Macro-CK type 1.

c. Mitochondrial CK (CKMi).

d. CK-BB.

C

What is the significance of the 48 to 72 hour mark following an Acute Myocardial Infarction regarding CK-MB?

a. It is the time when CK-MB begins to rise.

b. It is the exact time CK-MB reaches its peak.

c. It is the time when CK-MB returns to normal.

d. It is when CK-MB permanently disappears from the blood.

C

Which pulmonary condition is known to cause a mild or moderate elevation of Creatine Kinase?

a. Pulmonary fibrosis.

b. Emphysema.

c. Pulmonary infarction.

d. Asthma exacerbation.

C

Besides pulmonary infarction, which other pulmonary event may cause a mild or moderate elevation of CK in some patients?

a. Acute bronchitis.

b. Viral pneumonia.

c. Pulmonary edema.

d. Pleural effusion.

C

What is the primary difference in the physical measurement taken between the Tanzer-Gilvarg and Oliver-Rosalki methods at 340 nm?

a. Tanzer-Gilvarg measures color change; Oliver-Rosalki measures turbidity.

b. Tanzer-Gilvarg measures the formation of a precipitate; Oliver-Rosalki measures dissolution.

c. Tanzer-Gilvarg measures a decrease in absorbance (NADH -> NAD); Oliver-Rosalki measures an increase in absorbance (NADP -> NADPH).

d. They both measure the exact same increase in absorbance.

C

Why does the Oliver-Rosalki method require a pH of 6.8 compared to the 9.0 pH of the Tanzer-Gilvarg method?

a. To destroy the CK-MM fraction.

b. To inhibit the action of endogenous adenylate kinase.

c. Because it is the optimal pH for the reverse reaction (Creatine phosphate -> Creatine).

d. To ensure the complete precipitation of calcium ions.

C

Which condition would most likely result in a Creatine Kinase level that is exactly zero (undetectable)?

a. Severe muscular dystrophy.

b. Following an intramuscular injection.

c. A healthy individual with a strictly normal liver profile (since CK is not in the liver, its absence in liver doesn't mean it's zero in serum; serum CK is normally 34-171 U/L. Trick question, but based on text, CK is simply "not present in LIVER").

d. End-stage renal failure.

C

What is the relative speed of the Oliver-Rosalki method compared to the Tanzer-Gilvarg method?

a. 10 times slower.

b. Exactly the same speed.

c. 2-6 times faster.

d. 100 times faster.

C

Which of the following is considered a source of energy produced by the CK reaction?

a. Pyruvate.

b. Lactate.

c. Phosphocreatine.

d. Glucose-6-phosphate.

C

Which macro-enzyme form of CK migrates between CK-MB and CK-MM on electrophoresis?

a. Macro-CK type 2.

b. Mitochondrial CK.

c. Macro-CK type 1.

d. CK-BB.

C

Which of the following represents the correct sequence of reactions in the Tanzer-Gilvarg method?

a. Creatine phosphate + ADP -> Creatine + ATP -> ATP + glucose -> ADP + G6P -> NADPH.

b. Creatine + ATP -> Creatine phosphate + ADP -> ADP + phosphoenolpyruvate -> Pyruvate -> Lactate + NAD+.

c. Glucose + ATP -> G6P + ADP -> 6-phosphogluconate + NADPH.

d. Pyruvate + NADH -> Lactate + NAD+ -> Creatine phosphate.

C

What is the role of Hexokinase (HK) in the Oliver-Rosalki method?

a. It acts as the primary substrate.

b. It converts NADP to NADPH.

c. It immediately uses the ATP produced to phosphorylate glucose into G-6-P.

d. It reduces pyruvate to lactate.

C

In the context of a myocardial infarction, which of the following is true about CK-MB?

a. It stays elevated longer than LD.

b. It peaks later than AST.

c. It rises after 4-8 hours and peaks at 12-24 hours.

d. It remains elevated for over 10 days.

C

Which of the following is a key distinguishing characteristic of Creatine Kinase compared to Amylase or Lipase?

a. CK is primarily a digestive enzyme.

b. CK is strictly found in the pancreas.

c. CK is primarily an intracellular enzyme of muscle (and brain), elevated in muscle/cardiac damage, and entirely absent from the liver.

d. CK levels are solely influenced by dietary fat intake.

C

Which condition would NOT typically cause an elevation in Creatine Kinase, based on its tissue distribution?

a. Acute Myocardial Infarction.

b. Duchenne's muscular dystrophy.

c. Uncomplicated Viral Hepatitis (since CK is not present in the liver).

d. Severe trauma and crushing injuries.

C

If a laboratory technician leaves a serum sample for CK analysis on a brightly lit benchtop for an extended period, what is the likely outcome?

a. A false elevation due to light-induced activation.

b. A conversion of CK-MM to CK-MB.

c. A falsely decreased result because CK is inactivated by light.

d. No change, as light does not affect CK stability.

C

What is the specific component in the Oliver-Rosalki method that absorbs light at 340 nm?

a. NAD.

b. NADP.

c. NADPH.

d. Glucose-6-phosphate.

C

What is the specific component in the Tanzer-Gilvarg method that absorbs light at 340 nm?

a. NAD+.

b. ATP.

c. NADH.

d. Pyruvate.

C

n the calculation example provided, if total CK is 170 U/L and CK-MB is 8.5 U/L, what percentage of the total is CK-MB?

a. 1%.

b. 10%.

c. 5% (8.5 is 5% of 170, representing the typical upper limit or borderline for normal/abnormal <5%).

d. 20%.

D

Which of the following best summarizes the diagnostic significance of a markedly elevated CK-MM fraction?

a. It indicates a massive acute cerebral hemorrhage.

b. It strongly suggests an acute pulmonary embolism.

c. It is diagnostic for early-stage pancreatic carcinoma.

d. It points primarily to skeletal muscle injury or disease, as 95% of total CK is normally CK-MM.

D

How does the occurrence of a severe ischemic injury affect Creatine Kinase levels?

a. It causes a pronounced elevation (over 10 times normal).

b. It completely suppresses all CK activity.

c. It causes an isolated elevation of CK-BB only.

d. It causes a mild or moderate elevation (up to 5 times normal).

D

Which of the following is true regarding the use of CK-MB as a cardiac marker?

a. It is the most specific marker available and stays elevated for weeks.

b. It only rises after 48 hours, making it a late marker.

c. It is entirely non-specific and is elevated equally in liver disease.

d. It rises after 4-8 hours, peaks at 12-24 hours, and returns to normal rapidly (48-72 hours), making it useful for diagnosing re-infarction.

D

What distinguishes Mitochondrial CK (Macro-CK type 2) from the standard CK isoenzymes in terms of normal physiology?

a. It is the predominant fraction in healthy serum.

b. It acts specifically to inhibit the forward reaction.

c. It has the longest half-life of all isoenzymes (over 10 days).

d. It is found within the mitochondria and does not appear in circulation unless severe cellular damage occurs.

D

In the context of a suspected myocardial infarction, if a patient's blood is drawn 3 days (72 hours) after the onset of chest pain, what is the expected status of CK-MB?

a. It should just be beginning to rise.

b. It should be at its absolute peak concentration.

c. It should be higher than total CK.

d. It is expected to have returned to normal or near normal levels.

D

Which metallic ions act as inhibitors of Creatine Kinase?

a. Calcium and magnesium.

b. Sodium and potassium.

c. Iron and cobalt.

d. Zinc and manganese.

D

What is the fundamental principle behind why hemolysis falsely elevates CK levels?

a. Hemolysis releases large amounts of intracellular CK-MM.

b. Hemolysis releases free hemoglobin which mimics NADPH absorbance.

c. Hemolysis decreases the sample pH below 6.8.

d. Hemolysis releases adenylate kinase, an enzyme that catalyzes a similar reaction to CK.

D

Which of the following is NOT a characteristic of the Tanzer-Gilvarg method?

a. It measures the forward reaction (Creatine to Phosphocreatine).

b. It utilizes a pH of 9.0.

c. It measures a decrease in absorbance at 340 nm.

d. It is the most commonly performed method due to its speed (2-6x faster).

D

What is the primary reason the Oliver-Rosalki method is more commonly performed than the Tanzer-Gilvarg method?

a. It does not require any sulfhydryl activators.

b. It is entirely unaffected by hemolysis.

c. It uses a much simpler, single-step reaction.

d. It measures the reverse reaction, which proceeds 2-6 times faster than the forward reaction.

D

Which condition would most likely NOT be considered a cause for elevated Creatine Kinase, based on the provided text?

a. Polymyositis.

b. Delirium tremens.

c. Hypothyroidism.

d. Viral Hepatitis.

D

Which of the following isoenzymes migrates the shortest distance from the point of application toward the anode during electrophoresis?

a. CK-BB.

b. CK-MB.

c. Macro-CK type 1.

d. CK-MM.

D

In an electrophoretic separation of a healthy individual's serum, which band would appear the darkest and most prominent?

a. CK-BB.

b. CK-MB.

c. Mitochondrial CK.

d. CK-MM.

D

What does a CK-MB relative index (percentage) of <5% generally indicate?

a. The patient is currently experiencing a massive myocardial infarction.

b. The patient has Duchenne's muscular dystrophy.

c. The sample is severely hemolyzed.

d. A normal relative proportion, suggesting skeletal muscle rather than cardiac muscle is the primary source of any total CK elevation.

D

Which of the following represents the correct sequence of enzymes used in the Oliver-Rosalki coupled reaction?

a. Creatine Kinase -> Pyruvate Kinase -> Lactate Dehydrogenase.

b. Amylase -> Glucosidase -> Hexokinase -> G6PD.

c. Lipase -> Peroxidase.

d. Creatine Kinase -> Hexokinase -> Glucose-6-Phosphate Dehydrogenase.

D

Which of the following conditions is specifically noted to cause a pronounced elevation (5x or more) of CK due to skeletal muscle inflammation?

a. Myocardial infarction.

b. Severe ischemic injury.

c. Alcoholic myopathy.

d. Dermatomyositis and Polymyositis.

What is the role of Monothiolglycerol in the CK assay methodologies?

a. It acts as the primary buffer to maintain pH at 9.0.

b. It is the chromogen that absorbs light at 340 nm.

c. It serves to complex with and remove interfering zinc ions.

d. It acts as a necessary sulfhydryl activator.

D

What occurs during the final step of the Oliver-Rosalki method?

a. Pyruvate is reduced to lactate.

b. Creatine is phosphorylated.

c. ATP is generated from ADP.

d. Glucose 6-phosphate is oxidized, and NADP is reduced to NADPH.

D

Based on the time course graph for an AMI, what enzyme remains elevated the longest, well past the 5-day mark?

a. Total CK.

b. CK-MB.

c. AST.

d. LD (Lactate Dehydrogenase).

D

What distinguishes the structure of CK-MB from the other main CK isoenzymes?

a. It is the only monomeric isoenzyme.

b. It is exclusively composed of brain subunits.

c. It is exclusively composed of muscle subunits.

d. It is a hybrid type composed of one muscle (M) and one brain (B) subunit.

D

In evaluating a patient with severe muscle pain following a marathon (severe exercise), what would you expect their CK profile to look like?

a. Pronounced elevation primarily composed of CK-MB.

b. Pronounced elevation primarily composed of CK-BB.

c. Slight elevation primarily composed of Mitochondrial CK.

d. Mild or moderate elevation primarily composed of CK-MM.

D

If a laboratory does not add a sulfhydryl activator (like N-acetyl cysteine) to the reagent when testing for CK, what is the most likely consequence?

a. The reaction will proceed 2-6 times faster.

b. The reaction will permanently remain at a pH of 6.8.

c. The measurement will be falsely elevated due to adenylate kinase.

d. The Creatine Kinase enzyme will not be fully activated, leading to a falsely decreased or zero result.

D

Which of the following provides the best evidence that an elevated total CK is NOT due to a myocardial infarction?

a. The patient has a history of severe trauma.

b. The sample was drawn 1 hour after chest pain began.

c. The sample is severely hemolyzed.

d. The CK-MB fraction is less than 5% of the highly elevated total CK.

D

Which statement is true regarding the presence of Creatine Kinase in the brain (CK-BB)?

a. It has the longest half-life in circulation.

b. It is the predominant fraction found in healthy serum.

c. It migrates the slowest on electrophoresis.

d. It migrates the fastest toward the anode during electrophoresis.

D

In the Tanzer-Gilvarg method, why does the absorbance decrease at 340 nm as the reaction progresses?

a. Because NAD+ is being reduced to NADH.

b. Because the pH drops from 9.0 to 6.8.

c. Because the sulfhydryl activator is consumed.

d. Because NADH (which absorbs at 340 nm) is oxidized to NAD+ (which does not).

D

A patient in the ICU with acute agitated psychoses and a history of delirium tremens shows an elevated total CK. Based on the text, what degree of elevation is typically expected?

a. Pronounced elevation (100x normal).

b. No elevation is expected; CK should be normal.

c. An elevation consisting exclusively of CK-BB.

d. Mild or moderate elevation (up to 5 times normal).