clinical chemistry exam 3
Which of the following methods of measuring enzyme activity utilizes an increase in absorbance at 340 nm as an indicator reaction?
"Forward" LD reaction
Portal cirrhosis is a chronic disease of the liver. Observed on an electrophoretic serum protein pattern, a predominant characteristic of this disease is:
A bridging effect between the beta and gamma bands
Elevations in which of the following are MOST likely to indicate liver disease?
AST, ALT and ALK phosphatase
A reaction rate assay measures enzyme ____________________; an endpoint assay measures enzyme ______________________.
Activity; Activity
If serum proteins were immersed in a buffer of pH 8.6, which protein, albumin (pI = 4.7) or gamma globulin (pI = 7.6) would migrate the farthest by electrophoresis, and toward which electrode?
Albumin/anode
A protein that is normally produced by the fetus but is found in increased amounts in the amniotic fluid in cases of spina bifida is:
Alpha 1-fetoprotein
The acute phase reactant protein that also inhibits proteolysis and has the highest concentration within its globulin fraction is:
Alpha1-antitrypsin
Of the following, the only clinically analyzed enzyme in the urine is:
Amylase
Which of the following enzymes requires chloride (Cl-) as an activator?
Amylase
Azotemia refers to:
An increase in urea in blood
Common clinical laboratory methods for the measurement of serum albumin are based on the properties of albumin as a/an:
Binding protein
When myocardial infarction occurs, the first enzyme to reach peak elevation is:
CK
Of the following drug therapies, which is MOST likely to interfere with the Jaffe chemistry for measuring creatinine?
Cephalosporin
Given the following lab results, what is the most likely cause of this patient's BUN? BUN 45 mg/dL Creatinine 1.8 mg/dL Uric Acid 7 mg/dL pH 7.22 pCO 2 74.4 mm Hg pO 2 32.8 mm Hg O 2 sat. 51.3%
Congestive heart failure
Increased serum albumin concentrations are seen in which of the following conditions?
Dehydration
When a purified enzyme is used as a reagent, such as urease in the measurement of urea, the enzyme must be ________________ concentration so that the reaction follows _________________ kinetics.
Excess; first
True or false? In a "kinetic" or "rate" reaction, one spectrophotometric measurement is taken at the end of an incubation period.
False
True or false? Serum urea levels are less affected by diet and metabolism than are serum creatinine levels.
False
Which of the following enzymes detects very early changes in liver cell damage?
GGT
Of the following protein fractions, the one that is NOT produced in the liver is
Gamma globulin
The most sensitive enzymatic indicator for liver damage from ethanol intake is:
Gamma-glutamyl transferase (GGT)
In the Szasz method for gamma glutamyl transferase (GGT), the typical receptor molecule is:
Glycyl glycine
A glycoprotein that binds with hemoglobin to facilitate the removal of hemoglobin by the reticuloendothelial system is:
Haptoglobin
Urea:
Is synthesized from CO2 and ammonia
Which of the following enzyme tests is most affected by "hemolysis?
Lactate dehydrogenase
Which of the following enzymes has multiple molecular forms (isoenzymes) whose clinical significance is used in diagnosis?
Lactate dehydrogenase, creatine kinase, and alkaline phosphatase
The enzyme that is inhibited by hemoglobin is:
Lipase
The major causes of decreased plasma urea concentration include:
Low protein intake and sever liver disease
Which of the following is NOT considered a coenzyme?
Magnesium
The term below that is related to the ability of plasma proteins to maintain plasma water volume is:
Ontonic pressure
In the spectrophotometric determination of AST, malic dehydrogenase catalyzes the conversion of:
Oxalacetate to malate
Prostatic acid phosphatase measurement has been replaced by:
PSA
Which of the following electrophoretic media separates proteins primarily on the basis of molecular size?
Polyacrylamide gel
An elevated aldolase level and normal myoglobin is most indicative of:
Progressive muscular dystrophy
The major cellular origin of acid phosphatase activity in serum is:
Prostate
Monitoring of _______ in patients on chemotherapy due to leukemia, lymphoma or multiple myeloma is necessary to avoid nephrotoxicity.
Serum uric acid
In the commonly used ("Caraway") colorimetric method for uric acid in serum, interference from other reducing substances such as ascorbic acid is minimized by the addition of:
Sodium carbonate
Urea can be measured in all of the following ways EXCEPT:
The Caraway method
The biuret method for total serum protein is used for serum but not for protein in urine or cerebrospinal fluid (CSF) because:
The method is not sufficiently sensitive for use with urine or CSF
True or false? An enzymatic method for creatinine on the Vitros (Kodak Ektachem) analyzer uses the reagent enzyme creatinine amidohydrolase.
True
True or false? Indirect urea methods begin with the hydrolysis of urea to ammonia.
True
True or false? Serum uric acid levels may be elevated in patients undergoing cancer chemotherapy.
True
A toxic condition involving a very high serum level of urea and creatinine accompanied by failure of the three main functions of the renal system is referred to as:
Uremia
The abbreviated Modification of Diet in Renal Disease (MDRD) equation considers all of the following variables EXCEPT:
Urine creatinine concentration
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are both elevated in which of the following diseases?
Viral hepatitis
One extracellular enzyme whose serum activity is measured clinically is:
amylase
Peptide bonds of proteins bind with _________ ions of biuret reagent to produce a colored product.
cupric
One International Unit is defined as one __________ of substrate converted to product per ___________.
micromole; minute
The greatest tissue source of CK is:
skeletal muscle