Heme Derivatives (Chemistry) Flashcards
(32 cards)
Hemoglobin A1C represents:
A) valine substitution for glutamine at the 6th position of the beta chain of hemoglobin
B) ketone formation due to hydrolysis of the alpha and beta C-terminus forming an abnormal hemoglobin
C) glycosylation of valine in the polypeptide N-terminus of normal adult hemoglobin
D) glucose reduction in the presence of oxygen at the N-terminus of the polupeptide chains of hemoglobin
C) glycosylation of valine in the polypeptide N-terminus of normal adult hemoglobin
The principle of the occult blood test depends upon the:
A) coagulase ability of blood
B) oxidative power of atmospheric oxygen
C) hydrogen peroxide in hemoglobin
D) peroxidase-like activity of hemoglobin
D) peroxidase-like activity of hemoglobin
A breakdown product of hemoglobin is:
A) lipoprotein
B) bilirubin
C) hematoxylin
D) Bence Jones protein
B) bilirubin
Hemoglobin S can be separated from hemoglobin D by:
A) electrophoresis on a different medium and acidic pH
B) hemoglobin A2 quantitation
C) electrophoresis at higher voltage
D) Kleihavuer-Betke acid elution
A) electrophoresis on a different
On electrophoresis at alkaline pH, which of the following is the slowest migrating hemoglobin?
A) HgbA
B) HgbS
C) HgbC
D) HgbF
C) HgbC
The hemoglobin that is resistant to alkali (KOH) denaturation is:
A) A
B) A2
C) C
D) F
D) F
The following bilirubin results are obtained on a patient:
Day 1: 4.3 mg/dL (73.5 umol/L)
Day 2: 4.6 mg/dL (78.7 umol/L)
Day 3: 4.5 mg/dL (77.0 umol/L)
Day 4: 2.2 mg/dL (37.6 umol/L)
Day 5: 4.4 mg/dL (75.2 umol/L)
Day 6: 4.5 mg/dL (77.0 umol/L)
Given that the controls were within range each day, what is a probable explanatino for the result on day 4?
A) no explanation necessary
B) serum, not plasma, was used for testing
C) specimen had prolonged exposure to light
D) specimen was hemolyzed
C) specimen had prolonged exposure to light
Urobilinogen is formed in the:
A) kidney
B) spleen
C) liver
D) intestine
D) intestine
In bilirubin determinations, the purpose of adding a concentrated caffeine solution or methyl alcohol is to:
A) allow indirect bilirubin to react with color reagent
B) dissolve conjugated bilirubin
C) precipitate protein
D) prevent any change in pH
A) allow indirect bilirubin to react with color reagent
If the total bilirubin is 3.1 mg/dL (53.0 umol/L) and the conjugated bilirubin is 2.0 mg/dL (34.2 umol/L), the unconjugated bilirubin is:
A) 0.5 mg/dL (8.6 umol/L)
B) 1.1 mg/dL (18.8 umol/L)
C) 2.2 mg/dL (37.6 umol/L)
D) 5.1 mg/dL (87.2 umol/L)
B) 1.1 mg/dL (18.8 umol/L)
The principle of the tablet test for bilirubin in urine or feces is:
A) the reaction between bile and 2,4-dichloronitrobenzene to a yellow color
B) the liberation of oxygen by bile to oxidize orthotolidine to a blue-purple color
C) chemical coupling of bile with a diazonium slat to form a brown color
D) chemical coupling of bilirubin with a diazonium salt to form a purple color
D) chemical coupling of bilirubin with a diazonium salt to form a purple color
Ten heparinized plasma samples samples were assayed for bilirubin by Jendrassik-Grof method on analyzer 2, in a method comparison study. The results were all 10-20% higher from analyzer 2 most likely because:
A) the caffine-benzoate stabilizer in the 2nd analyzer prevented falsely decreased results as found in analyzer 1
B) fibrinogen in the plasma samples caused falsely decreased results in the Jendrassik-Grof method
C) alcohol reagents in the second method cause precipitation of proteins and increased background turbidity
D) hemolysis caused greater interference in method 1 than in method 2
C) alcohol reagents in the second method cause precipitation of proteins and increased background turbidity
Serial bilirubin determinations performed by Jendrassik-Grof method are charted below:
Day 1:
Time: 7 am
Assayed: 8 am
Result: 14.0 mg/dL (239.4 umol/L)
Day 2:
Time: 7 am
Assayed: 6 pm
Result: 9.0 mg/dL (153.9 umol/L)
Day 3:
Time: 6 am
Assayed: 8 pm
Result: 15.0 mg/dL (256.5 umol/L)
The best explanation for the results is:
A) sample on day 2 has mild hemolysis and hemoglobin deterioration
B) sample on day 2 has exposure to light
C) sample on day 2 shows normal day to day variation
D) reagent deterioration is evident on day 3
B) sample on day 2 has exposure to light
In the liver, bilirubin is concerted to:
A) urobilinogen
B) urobilin
C) bilirubin-albumin complex
D) bilirubin diglucuronide
D) bilirubin diglucuronide
In which of the following disease states is conjugated bilirubin a major serum component?
A) biliary obstruction
B) hemolysis
C) neonatal jaundice
D) erythroblastosis fetalis
A) biliary obstruction
Kernicterus is an abnormal accumulation of bilirubin in:
A) heart tissue
B) brain tissue
C) liver tissue
D) kidney tissue
B) brain tissue
In which of the following conditions does decreased activity of glucuronyl transferase result in increased unconjugated bilirubin and kernicterus in neonates?
A) Gilbert disease
B) Rotor disease
C) Dubin-Johnson syndrome
D) Crigler-Najjar syndrome
D) Crigler-Najjar syndrome
A 21 year old with nausea, vomiting, and jaundice has the following laboratory findings:
total serum bilirubin
Patient Value: 8.5 mg/dL (145.4 umol/L)
Reference Range: 0-1.0 mg/dL (0.0-17.1 umol/L)
conjugated serum bilirubin
Patient Value: 6.1 mg/dL (104.3 umg/dL)
Reference Range: 0-0.5 mg/dL (0.0-8.6 umol/L)
urine urobilinogen: increased
fecal urobilinogen: decreased
urine bilirubin: positive
AST
Patient Value: 300 U/L
Reference Range: 0-50 U/L
alkaline phosphatase
Patient Value: 170 U/L
Reference Range: 0-150 U/L
These can best be explained as representing:
A) unconjugated hyperbilirubinemia, probably due to hemolysis
B) unconjugated hyperbilirubinemia, probably due to toxic liver damage
C) conjugated hyperbilirubiemia, probably due to hepatocellular disease
D) conjugated hyperbilirubinemia, probably due to hepatocellular obstruction
C) conjugated hyperbilirubiemia, probably due to hepatocellular disease
A stool specimen that appears black and tarlike should be tested for the presence of:
A) occult blood
B) fecal fat
C) trypsin
D) excess mucus
A) occult blood
What substance gives feces its normal color?
A) uroerythrin
B) urochrome
C) urobilin
D) urobilinogen
C) urobilin
A condition in whihc erythrocute protoporhyrin is increased is:
A) acute intermittent prophyria
B) iron deficiency anemia
C) porphyria cutanea tarda
D) acute porphyric attack
B) iron deficiency anemia
The definitive diagnosis for hereditary coproporphyria (HPC) is a markedly increased:
A) urine delta-aminolevulinic acid (ALA)
B) urine prophobilinogen (PBG)
C) fecal coproporphurin III
D) erythrocyte protoprophyrin
C) fecal coproporphurin III
A fresh urine sample is received for analysis for “porphyrins” or “porphuria” without further information or speifications. Initial analysis should include:
A) porphyrin screen and quantitative total porphyrin
B) quantitative total porphyrin and porphobilinogen screen
C) porphyrin and porphobilinogen screen
D) porphobilinogen screen and ion-exchange analysis for porphobilinogen
C) porphyrin and porphobilinogen screen
Which of the following enzymes of heme biosynthesis is inhibited by lead?
A) aminolevulinate synthase
B) porphobilinogen synthase
C) uroporphyrinogen synthase
D) bilirubin synthetase
B) porphobilinogen synthase
