Deck 11: Nonprotein Nitrogen Questions

Question 1

Which of the following is NOT an NPN substance?

A) Urea
B) Ammonia
C) Creatinine
D) Troponin T

Answer 1

Troponin T

Question 2

Urea/BUN is produced from:

A) The catabolism of proteins and amino acids.
B) Oxidation of purines.
C) Oxidation of pyrimidines.
D) The breakdown of complex carbohydrates.

Answer 2

The catabolism of proteins and amino acids.

Question 3

An elevated BUN usually indicates:

A) Liver disease.
B) Kidney disease.
C) Pancreatic disease.
D) Myocardial infarction.

Answer 3

Kidney disease.

Question 4

BUN is increased with:

A) A high protein diet.
B) A low protein diet.
C) A high carbohydrate diet.
D) It is not affected by diet.

Question 5

In the Berthelot method, BUN is measured by reaction with:

A) Sodium hydroxide and arsenomolybdate.
B) Dinitrophenylhydrazine.
C) Phenol and sodium hypochlorite.
D) Dinitrocarbazone.

Question 6

Urea can be measured by incubation with urease followed by all of the following EXCEPT:

A) Formation of a colored product by reaction with diacetyl.
B) Measurement of increased conductivity.
C) Ion-selective electrode measurement of the ammonia produced.
D) NADH consumption in a reaction catalyzed by glutamate dehydrogenase.

Question 7

Normal values for urea are generally expressed as urea nitrogen. If it is necessary to convert urea nitrogen values to urea, the concentration may be calculated easily by multiplying the urea nitrogen value by:

A) 0.47.
B) 1.47.
C) 2.14.
D) 28.
E) 60.

Question 8

A BUN of 10 mg/dL is obtained by a technologist. What is the urea concentration?

A) 25.0 mg/dL
B) 21.4 mg/dL
C) 18.4 mg/dL
D) 9.3 mg/dL

Question 9

Renal azotemia is found in:

A) Advanced cirrhosis.
B) High protein diets.
C) Nephrotic syndrome.
D) Dehydration.

Question 10

Prerenal hyperuricemia is caused by:

A) Dehydration.
B) Uremia.
C) Bladder tumors.
D) Prostatic hypertrophy.

Question 11

Creatinine is formed from the:

A) Oxidation of creatine.
B) Oxidation of protein.
C) Deamination of dibasic amino acids.
D) Metabolism of purines.

Question 12

Creatinine reacts with strong alkaline picrate to form a yellow-red compound. This reaction is:

A) Nessler's reaction.
B) Ehrlich's diazo reaction.
C) Jaffe reaction.
D) Lieberman-Burchard reaction.

Question 13

Creatinine levels are usually:

A) 0.1-0.6 mg/dL.
B) 0.8-1.2 mg/dL.
C) 1.5-2.5 mg/dL.
D) 3.0-5.0 mg/dL.

Question 14

Creatinine would be increased in which of the following?

A) Reye's syndrome
B) Myocardial infarction
C) Muscular dystrophy
D) Hepatitis

Question 15

Serum urea nitrogen and serum creatinine determinations are frequently requested together so that their ratio may be evaluated. What is the range of the normal ratio of urea nitrogen to creatinine?

A) 1/1 and 10/1
B) 12/1 and 20/1
C) 15/1 and 20/1
D) 20/1 and 30/1
E) 25/1 and 30/1

Question 16

A high BUN/creatinine ratio with an elevated creatinine is usually seen in:

A) Liver disease.
B) Low protein intake.
C) Tubular necrosis.
D) Postrenal azotemia.

Question 17

A technologist obtains a BUN value of 61 mg/dL and serum creatinine value of 3.5 mg/dL on a patient. The BUN/Creatinine ratio indicates:

A) Renal failure.
B) Liver failure.
C) Gout.
D) Prerenal failure.

Question 18

Increased uric acid is found in each of the following conditions EXCEPT:

A) Gout.
B) Hypothyroidism.
C) Lesch-Nyhan syndrome.
D) Renal failure.

Question 19

All of the following conditions are associated with hyperuricemia EXCEPT:

A) Liver failure.
B) Malignancy.
C) Renal failure.
D) Primary "essential" overproduction of uric acid.

Question 20

Uric acid values are usually elevated in patients with leukemia because of the breakdown of:

A) Proteins.
B) Nucleic acids (adenine and guanine).
C) Amino acids.
D) Epinephrine.

Question 21

Uric acid may be determined with:

A) The enzyme urease.
B) The enzyme uricase.
C) Formation of a blue color with phosphotungstic acid.
D) Formation of a red color with diazotized sulfanilic acid.
E) both B and C above

Question 22

The creatinine clearance test is routinely used to assess the glomerular filtration rate. Given the following information for an average size adult, calculate a creatinine clearance.
Urine creatinine: 120 mg/dL
Plasma creatinine: 1.2 mg/dL
24h urine volume: 1520 ml

A) 10.6 mL/min
B) 15.2 mL/min
C) 63.3 mL/min
D) 94.7 mL/min
E) 105.6 mL/min

Question 23

The chief source of error in kidney evaluation using the excretion rate of substance is:

A) The chemical method of analysis.
B) The timing and completeness of collection.
C) The test chosen for the evaluation.
D) The day-to-day variation of renal function.

Question 24

Leukocyte reagent strips are used to detect leukocyte:

A) Peroxidase.
B) Esterases.
C) Hydroxylase.
D) Phosphatase.