Clinical Chem Test 3

Which of the following is a qualitative screening test for porphobilinogen that may be performed to aid in the diagnosis of the porphyrias? a. Watson-Schwartz test b. Gutman test c. Caraway test d. Jendrassik-Grof test

a

Which of the following statements regarding urobilinogen is true? a. It is formed in the intestines by bacterial reduction of bilirubin b. It consists of a single water-soluble bile pigment c. It is measured by its reaction with p-aminosalicylate d. In hemolytic anemia, it is decreased in urine and feces

a

Which of the following would indicate prehepatic liver problems? a. Total Bilirubin increased; Direct Bilirubin normal; indirect Bilirubin increased b. Total Bilirubin increased; Direct Bilirubin increased; Indirect Bilirubin increased c. Total Bilirubin increased; Direct Bilirubin normal; Indirect Bilirubin normal d. Total Bilirubin increased; Direct Bilirubin increased; Indirect Bilirubin normal

a

Which statement regarding total and direct bilirubin levels is true? a. Total bilirubin level is a less sensitive and less specific marker of liver disease than the direct level b. Direct bilirubin exceeds 3.5mg/dL in most cases of hemolytic anemia c. Direct bilirubin is normal in cholestatic liver disease d. The ratio of direct to total bilirubin exceeds 0.40 in hemolytic anemia

a

Which of the following is a common cause of post hepatic jaundice? a. Hemolytic disease of the newborn (HDN) b. Alcoholism c. Gallstones d. Sickle cell anemia

c

Which of the following preanalytical errors most commonly cause false increases in serum enzyme measurements? a. The patient was not fasting prior to blood draw b. The blood sample was not maintained on ice upon collection and during transport to the laboratory c. The serum was not separated from red blood cells within 1 hour d. The blood sample was not protected from light upon collection and during transport to the laboratory

c

Which of the following statement regarding transaminases is true? a. ALT is increased in infectious mononucleeosis, but AST is usually normal b. ALT is often increased in muscular disease, pancreatitis, and lymphoma c. ALT is more specific for liver diseases than is AST d. Substrate depletion seldom occurs in assays of serum from hepatitis cases

c

A healthy, asympotomatic athletic male age 25 was seen by a physician for a routine physical. A chemical profile was run and an elevated CK was found. This could be explained by: a. A subclinical case of mononucleosis b. A recent stroke c. Myocardial infarction d. Heavy physical exercise

d

A patient has a plasma CK-MB of 14 ug/L at admission and a total CK of 170 IU/L. Serum myoglobin is 130 ug/L and TnI is 1.6 ug/L. Three hours later, the TnI is 3.0 ug/L. Which statement best describes this situation? a. These results are consistent with skeletal muscle damage associated with a crush injury that elevated the CK-MB b. Further testing 6-12 hours post admission is required to establish a diagnosis of AMI c. A second CK-MB and myoglobin test should have been performed at 3 hours post admission to confirm AMI d. This patient has had an AMI and further testing is unnecessary

d

A serum TnT concentration is of most value to the patient with an MI when a. The CK-MB has already peaked and returned to normal concentrations b. The onset of symptoms is within 3 to 6 hours of ample being drawn c. The myoglobin concentration is extremely elevated d. The TnI concentration has returned to normal concentrations

d

Bilirubin is transported from reticuloendothelial cells to the liver by: a. Haptoglobin b. Transferrin c. Bilirubin-binding globulin d. Albumin

d

Elevation of serum amylase and lipase is commonly seen in: a. Gallbladder disease b. Acute appendicitis c. Acid reflux disease d. Acute pancreatitis

d

Enzymes that catalyze the transfer of groups between compounds are classified as belonging to which enzyme class? a. Hydrolases b. Lyases c. Oxidoreductases d. Transferases

d

If elevated, which laboratory test would support a diagnosis of congestive heart failure? a. Homocysteine b. Troponin (TnI or TnT) c. Albumin cobalt binding d. B-type natriuretic peptide (BNP)

d

LD isoenzymes are composed of: a. A combination of four subunits b. Two units made up of five subunits c. Two subunits d. Five combinations made up of two subunits

d

Which of the following tests is most specific for cardiac damage and remains clinically useful over the longest period of time? a. CK-MB b. Total CK c. Myoglobin d. Troponin I

d

Which of the three protein subunits of troponin binds calcium ions? a. Troponin A b. Troponin I c. Troponin T d. Troponin C

d

An example of using enzymes as reagents in the clinical laboratory is: a. The hexokinase glucose method b. The biuret total protein method c. The diacetyl monoxime blood urea nitrogen (BUN) method d. The alkaline picrate creatinine method

a

As a reduction product of bilirubin catabolism, this compound is partially reabsorbed from the intestines through the portal circulation for reexcretion by the liver. What is this compound? a. urobilinogen b. azobilirubin c. biliverdin d. urobilin

a

Elevation of the tissue enzymes in serum may be used to detect: a. Tissue necrosis or damage b. Inflammation c. Diabetes mellitus d. Infectious diseases

a

Enzyme reaction rates are increased by increasing temperatures until they reach the point of denaturation at: a. 40-60C b. 25-35C c. 100C d. 37C

a

Hepatocellular damage may be best assessed by which of the following parameters? a. serum AST and ALT levels b. GGT and ALP c. bilirubin, GGT, and ALP d. ammonia and urea

a

In noncompetitive inhibition the inhibitor can bind with: a. The enzyme b. Only the substrate c. Both the enzyme and the enzyme substrate complex d. The enzyme substrate complex

a

In which of the following disease states would you see an elevation in total bilirubin and conjugated bilirubin only? a. biliary obstruction b. hemolysis c. neonatal jaundice d. hepatitis

a

The definition of Km is the: a. The concentration of substrate at which 1/2 Vmax is reached b. The concentration of substrate c. The concentration of substrate where Vmax is reached d. The concentration of enzyme where Vmax is reached

a

The main purpose of porphyrin in the body is to: a. Contribute to the synthesis of heme b. Transport iron c. Combine with free hemoglobin d. Carry oxygen to the tissue

a

The primary route(s) of excretion for protoporphyrin (PROTO), uroporphyrin (URO), and coproporphyrin (COPRO) are: a. URO is excreted primarily in the urine, PROTO in the feces, and COPRO in either b. URO is excreted primarily in the urine, PROTO and COPRO in the feces c. URO is excreted primarily in the feces, PROTO and COPRO in the urine

a

The saccharogenic method for amylase determination measures: a. the amount of product produced b. the amount of substrate consumed c. the amount of starch present d. the amount of iodine present

a

The two main sites of production of heme are a. Liver and bone marrow b. Heart and lungs c. Muscle and blood d. Liver and spleen

a

To aid in the diagnosis of skeletal muscle disease, which of the following serum enzyme measurements would be of most use? a. creatine kinase b. alkaline phosphatase c. aspartate aminoctransferase d. alanine aminotransferase

a

What compound may be detected by observing its orange-red fluorescence in acid solution? a. Porphobilinogen b.Aminolevulinic acid c. Coproporphyrin d. Uroporphyrinogen

a

What is the use of a first order reaction? a. To measure the substrate concentration b. To measure the enzyme concentration c. To measure the enzyme activity d. There is no use for it

a

What would happen if you increased the substrate concentration in uncompetitive inhibition? a. There would be more binding sites available for the inhibitor b. The inhibitor would be neutralized c. The inhibitor could be overcome d. Nothing will change

a

When measuring enzyme activity, if the instrument is operating 5 degree lower than the temperature prescribed for the method, how will the results be affected? a. Lower than expected b. Higher than expected c. Varied, showing no particular pattern d. All will be clinically abnormal

a

Which condition is caused by deficient secretion of bilirubin into bile canaliculi? a. Dublin-Johnson syndrome b. Crigler-Najjar syndrome c. Neonatal hyperbilirubinemia d. Gibert disease

a

Which forms of hyperbilirubinemia is caused by an inherited absence of UDP-glucoronyl transferase? a. Crigler-Najjar syndrome b. Rotor syndrome c. Gilbert's syndrome d. Dubin-Johnson syndrome

a

Which of the following analytes has the highest specificity for cardiac injury and preferred marker for myocardial infarction? a. cTnI or cTnT b. CK-MB mass assays c. Total CK d. AST (GOT)

a

Which of the following cardiac markers is the most useful indicator of congestive heart failure? a. BNP b. LD1 c. CK-MB d. TnI

a

Which of the following enzyme patterns is MOST diagnostic of Duchennetype muscular dystrophy? a. Total CK level that is 50 to 100 times the ULN b. Total CK level that is 5 to 10 times the ULN c. Total CK level that is 1,000 times the ULN d. Total CK level that is 25 times the ULN

a

Which substrate concentration is needed to achieve zero order conditions? a. Greater than 99xKm b. Less than 10xKm c. [S]=0 d. [S]=Km

a

Why doesn't the Vmax change in competitive inhibition? a. Because the inhibitor binds only to the enzyme b. Because the inhibitor binds only to the product c. Because the inhibitor binds only to the E+S complex d. Because the inhibitor binds only to the substrate

a

Why would the Jendrassic-Grof procedure be preferred over the Malloy-Evelyn procedure? a. There is less interference by hemoglobin b. There is less interference by lipids c. There is less interference by bilirubin d. None of the others

a

Which condition produces the highest elevation of serum lactate dehydrogenase? a. Pernicious anemia b. Myocardial infarction c. Muscular dystrophy d. Acute hepatitis

a.

In which of the following does no activity of glucoronyl transferase result in increased unconjugated bilirubin and kernicterus in neonates and eventual death within 18 months? a. Gilbert's disease b. Dublin-Johnson syndrome c. Crigler-Najjar syndrome d. intravascular hemolysis

c

Other than an AMI, what other conditions may cause an very large increase in CK-MB? a. Chest trauma b. Electrocution c. All of the others d. Post angioplasty

c

What protein is the most specific to cardiac damage? a. Myoglobin b. CK c. Troponin I&T d. Chicken (great protein)

c

When AMI occurs, in what order will the enzymes AST, CK, and LDH become elevated in the serum? a. AST, LD, CK b. CK, LD, AST c. CK, AST, LD d. LD, CK, AST

c

Which of the following analytes is the best indicator of hepatobiliary damage? a. AST b. ALT c. ALP d. bilirubin

c

Which of the following cardiac markers is consistently increased in persons who exhibit unstable angina? a. Myoglobin b. Troponin C c. Troponin T d. CK-MB

c

Which of the following conditions is caused by deficient secretion of bilirubin into the bile canaliculi? a. Gilbert's disease b. physiologic jaundice of the newborn c. Dublin-Johnson syndrome d. hemolytic jaundice

c

Which of the following conditions would result in elevations in primarily conjugated bilirubin? a. Crigler-Najjar syndrome b. Physiologic jaundice of the newborn c. Dubin-Johnson syndrome d. Gilbert syndrome

c

Which of the following enzymes is most useful in establishing the hepatic origin of an elevated serum alkaline phosphatase? a. Lactate dehydrogenase b. Alanine aminotransferase (ALT) c. 5'-Nucleotidase d. Aspartate aminotransferase (AST)

c

Which of the following enzymes is responsible for the conjugation of bilirubin take place? a. Glutamate dehydrogenase b. Alkaline phosphatase c. UDP glucuronyl transferase d. Leucine aminopeptidase

c

Which of the following is NOT a function of the liver? a. Producing procoagulants b. Storage c. Antibody production d. Detoxification

c

Which of the following statements correctly describes alkaline phosphatase? a. decrease in Paget disease b. decreased in the 3rd trimester of pregnancy c. increased in obstructive jaundice d. primarily found in cardiac muscle

c

Which statement best describes the clinical use of measuring NT-proBNP? a. Used to assess risk of coronary heart disease b. Used to assess risk of angina c. Used to assess individuals treated with nesiritide (human BNP recombinant) d. Used to assess individuals treated with vitamin B

c

The definition of zero order reaction is: a. Where the concentration of the enzyme is too low to have a reaction b. Where the rate of the reaction is dependent of the substrate concentration c. The concentration of the substrate where 1/2 Vmax is reached d. Where the rate of the reaction is independent of the substrate concentration

d

The term delta-bilirubin refers to: a. Water-soluble bilirubin b. Free conjugated bilirubin c. Direct-reacting bilirubin d. Bilirubin tightly bound to albumin

d

Troponin values parallel what other test result? a. LD b. CK Total c. BNP d. CK-MB

d

What is a simple method to separate ALP isoenzymes a. Electrophoresis b. Heat denaturation at 37 degrees c. Freezing of the serum d. Heat denaturation at 56 degrees

d

When measuring CK-MB, which of the following would provide the most sensitive method? a. electrophoretic b. colorimetric c. kinetic d. mass immunoassay

d

When reaction is performed in a zero order kinetics: a. The substrate concentration is very low b. The rate of reaction is directly proportional to the substrate concentration c. The enzyme level is always high d. The rate of the reaction is independent of the substrate concentration

d

Which CK isoenzyme is elevated in muscle diseases? a. CK-MB b. CK-NN c. CK-BB d. CK-MM

d

Which cardiac marker is elevated for the longest period after myocardial infarction (MI)? a. CK-MB b. Myoglobin c. Troponin I d. Troponin T

d

Which of the following enzymes would best aid in identifying hepatobiliary disease? a. Ammonia b. Aspartate aminotransferase (AST) c. Alanine aminotransferase (ALT) d. Alkaline phosphatase (ALP)

d

Which of the following fractions of bilirubin is water soluble and reacts with diazo reagent without the addition of an accelerator? a. Total bilirubin b. Unconjugated bilirubin c. Indirect bilirubin d. Conjugated bilirubin

d

Which of the following is FALSE about cardiac troponin I (TnI) as it relates to AMI? a. Increase above reference interval seen in 3 to 6 hours b. Measure initially and serially in 3- to 6-hour intervals c. Remain elevated 5 to 10 days d. Expressed in regenerating & diseased skeletal muscle and cardiac muscle disorders

d

Which of the following is NOT a feature of an ideal cardiac marker? a. High sensitivity b. Absolute specificity c. Close estimation of the magnitude of cardiac damage d. Ability to predict future occurrence of cardiac disease

d

Which of the following is a characteristic of conjugated bilirubin? a. It reacts more slowly than unconjugated bilirubin b. It has the same absorbance properties as unconjugated bilirubin c. It is more stable than unconjugated bilirubin d. It is water soluble

d

Which of the following markers of inflammation circulates in serum bound to LDL and HDL? a. Lipoprotein-associated phospholipase A2 b. CK-MB c. cTnI d. hsCRP

d

Which of the following would indicate post hepatic obstruction? a. Total bilirubin increased; direct bilirubin decreased; indirect bilirubin normal b. Total bilirubin increased; direct bilirubin normal; indirect bilirubin normal c. Total bilirubin increased; direct bilirubin normal; indirect bilirubin increased d. Total bilirubin increased; direct bilirubin increased; indirect bilirubin increased

d

Which protein is most sensitive to an AMI? a. Troponin b. CK-MB c. CK d. Myoglobin

d

In the liver, bilirubin is conjugated in the presence of which of the following? a. beta-glucuronidase b. bilirubin oxidase c. UDP-glucuronyl transferase d. peroxidase

c

An enzyme functions by: a. Lowering the energy of activation b. Altering the pH of the reaction c. Increasing the energy of activation d. Altering the structure of the substrate

a

A 4-year-old male child is brought to the pediatrician because the parents are concerned about the child's frequent falling, which results in bruising. The parents indicated that the child has difficulty running, walking, standing up, climbing stair, and even sitting up straight. The child also appears somewhat weak. Which of the following results is NOT consistent with the most likely diagnosis? a. Moderately elevated AST b. Moderately elevated ALP c. moderately elevated LD d. markedly elevated CK

b

A serum TnT concentration is of most value to the patient with an AMI when: a. The onset of symptoms is w/in 3 - 6 hours of the sample being drawn b. The TnI conc has returned to nml conc c. The CK-MB has already peaked & returned to nml concentrations d. The myoglobin conc is extremely elevated

b

Activation energy is: a. The energy needed for an enzyme reaction to stop b. Decreased by enzymes c. Increased by enzymes d. Very high in catalyzed reactions

b

An EDTA sample for TnI assay gives a result of 0.04ng/mL (reference range 0-0.03 ng/mL). The test is repeated 3 hours later on a new specimen and the result is 0.06 ng/mL. A third sample collected 6 hours later gives a result of 0.07 ng/mL. The ECG showed no evidence of ST segment elevation (STEMI). What is the most likely explanation? a. Heparin should have been used instead of EDTA, which causes false positives b. The patient has suffered cardiac injury c. The patient has had an ischemic episode without cardiac injury d. A false-positive result occurred due to matrix interference

b

For assessing carcinoma of the prostate, quantification of PSA has virtually replaced the measurement of which of the following enzymes? a. alkaline phosphatase b. acid phosphatase c. alanine aminotransferase d. trypsin

b

In acute pancreatitis, a significant increase in which serum enzyme would be expected diagnostically? a. Creatine kinase b. Amylase c. Alkaline phosphatase d. Aspartate aminotransferase

b

In which of the following types of cells does the conjugation of bilirubin take place? a. Phagocytic cells b. Hepatocytes c. Kupffer cells d. Macrophages

b

Select the most sensitive marker for alcoholic liver disease a. GLD b. GGT c. ALT d. ALP

b

The activity of enzymes in serum may be determined rather than concentration because: a. The amount of enzyme is too high to measure b. The amount of enzyme is too low to measure c. There is not enough substrate d. The temperature is too high

b

The isoenzyme LD-4 and LD-5 are elevated in: a. renal disease b. liver disease c. pulmonary embolism d. myocardial infarctions

b

The properties of enzymes are correctly described by which of the following statements? a. Enzymes are stable proteins b. Enzymes are protein catalysts of biological origin c. Enzymes affect the rate of a chemical reaction by raising the activation energy needed for the reaction to take place d. Enzyme activity is not altered by heat denaturation

b

URO is excreted primarily in the feces, PROTO in the urine, and COPRO in either What compound chelates iron and is the immediate precursor of heme formation? a. Uroporphyrinogen III b. Protoporphyrin IX c. Porphobilinogen d. Protoporphyrinogen IX

b

Which compounds originally condense to form delta-aminolevulinic acid? a. Oxoglutarate and aspartate b. Succinyl coenzyme A and glycine c. Isocitrate and coenzyme II d. Oxalacetate and malate

b

Which of the following cardiac markers is the first to increase after an acute myocardial infarction? a. CK-MB b. Myoglobin c. Lactate dehydrogenase d. Troponin

b

Which of the following fractions of bilirubin in high concentrations is associated with kernicterus in newborns? a. delta bilirubin b. unconjugated bilirubin c. conjugated bilirubin d. unconjugated and delta bilirubin

b

Which of the following is the most sensitive test for hepatobiliary disorders? a. ALT b. GGT c. LD d. AST

b

Which of the following may cause prehepatic jaundice? a. Gilbert syndrome b. Hemolytic disease of the newborn (HDN) c. Cirrhosis d. Gall stones

b

Which of the following would indicate intrinsic liver disease? a. Total Bilirubin increased; Direct Bilirubin normal; Indirect Bilirubin increased b. Total Bilirubin increased; Direct Bilirubin increased; Indirect Bilirubin increased c. Total Bilirubin increased; Direct Bilirubin normal; Indirect Bilirubin normal d. Total Bilirubin increased; Direct Bilirubin increased; Indirect Bilirubin normal

b

Which reagent is used in the Jendrassik-Grof method to solubilize unconjugated bilirubin? a. 50% methanol b. Caffeine c. N-butanol d. Acetic acid

b

Which test becomes abnormal and used in risk assessment for the earliest stage of the acute coronary syndrome? a. Myoglobin b. High-sensitivity C-reactive protein (hsCRP) c. Myosin light chain I d. Ck-MB isoforms

b

A holoenzyme is defined as: a. An apoenzyme bound to an activator (Mg++ as an example) b. An apoenzyme and prosthetic group that are loosely bound c. An apoenzyme and prosthetic group that are tightly bound d. An isoenzyme bound to a apoenzyme

c

A normal myoglobin concentration 8 hours after the onset of symptoms of a suspected MI will: a. Essentially rule out an acute MI b. Provide a definitive diagnosis of acute MI c. Be interpreted with careful consideration of the TnT concentration d. Give the same information as a total CK-MB

c

A urinalysis dipstick test indicated that urobilinogen was absent. Which condition does this support? a. Hepatitis A acute infection b. Defective liver cell function c. Biliary obstruction d. Hepatocellular disease

c

Creatine kinase elevations are common in myocardial infarctions. Which of the following diseases will also raise the total CK but will not raise the MB above 5 percent? a. Hepatitis b. Acute pancreatitis c. Duchenne Muscular Dystrophy d. Megaloblastic anemia

c

How are ALT and AST similar? a. They both move a terminal carbohydrate group b. They both use aspartate as a substrate c. They both move a terminal amine group d. They both use alanine as a substrate

c