(26) RA VICTORINO Flashcards
Which one of the following is not an NPN substance?
a. Allantoin
b. Ammonia
c. Creatinine
d. Urea
a. Allantoin
Which compound constitutes nearly half of the NPN substances in the blood?
a. Ammonia
b. Creatine
c. Urea
d. Uric acid
c. Urea
A technologist reports urea N of 9 mg/dL. What is the urea concentration for
this sample?
a. 3.2 mg/dL
b. 4.2 mg/dL
c. 18.0 mg/dL
d. 19.3 mg/dL
d. 19.3 mg/dL
Which blood collection tube additive can be used to collect a specimen for
measurement of urea?
a. Ammonium
b. Lithium heparin
c. Sodium citrate
d. Sodium fluoride
b. Lithium heparin
In the clinical laboratory, urea N is measured most often using
a. Conductivity
b. Enzymatic reactions
c. Isotope dilution mass spectrometry
d. Multilayer film formats
b. Enzymatic reactions
Elevated blood urea concentration is termed
a. Azotemia
b. BUN
c. Uremia
d. Uremic syndrome
a. Azotemia
Prerenal azotemia is caused by
a. Acute renal failure
b. Chronic renal failure
c. Congestive heart failure
d. Urinary tract obstruction
c. Congestive heart failure
A technologist obtains a urea N value of 61 mg/dL and a serum creatinine
value of 2.5 mg/dL on a patient. These results indicate
a. Congestive heart failure
b. Dehydration
c. Glomerular nephritis
d. Urinary tract obstruction
d. Urinary tract obstruction
Uric acid is the final product of
a. Allantoin metabolism
b. Amino acid metabolism
c. Purine metabolism
d. The urea cycle
c. Purine metabolism
Sources of error in measurement of uric acid include
a. Assay interference
b. Competition from alternate purine substrates
c. Narrow spectrophotometer bandwidth
d. Nonspecific enzyme activity
a. Assay interference
Which condition is not associated with elevated plasma uric acid
concentration?
a. Allopurinol overtreatment
b. Gout
c. Lesch-Nyhan syndrome
d. Renal disease
a. Allopurinol overtreatment
Complete deficiency of hypoxanthine–guanine phosphoribosyltransferase
results in which disease?
a. Allantoinism
b. Glycogen storage disease
c. Lesch-Nyhan syndrome
d. Megaloblastic anemia
c. Lesch-Nyhan syndrome
Uric acid nephrolithiasis refers to
a. Acidification of the urine to dissolve renal calculi
b. Formation of renal calculi composed of uric acid
c. Precipitation of urates in the urinary tract
d. Saturation of the kidney with uric acid
b. Formation of renal calculi composed of uric acid
A 45-year-old male presents to the emergency department complaining of
intense joint pain. The previous night the patient experienced similar pain
accompanied by inflammation and redness of his wrists and large toe. The
physician on-call orders testing for serum uric acid concentration. Which
laboratory results and diagnosis are consistent with the physician’s
assessment? The reference interval for uric acid is 3.5 to 7.2 mg/dL.
a. Uric acid 1.9 mg/dL; Fanconi syndrome
b. Uric acid 1.0 mg/dL; hereditary xanthinuria
c. Uric acid 9.1 mg/dL; alcoholism
d. Uric acid 9.1 mg/dL; gout
d. Uric acid 9.1 mg/dL; gout
Which statement describes creatinine biosynthesis accurately?
a. Creatine is phosphorylated in the liver to form phosphocreatinine.
b. Creatine phosphate undergoes spontaneous cyclization to form
creatinine.
c. Creatinine is formed from creatine and creatine phosphate in the liver.
d. Creatinine is synthesized from arginine, glycine, and methionine in the
liver.
c. Creatinine is formed from creatine and creatine
Substances known to increase results when measuring creatinine by the Jaffe
reaction include all of the following EXCEPT
a. Ascorbic acid
b. Bilirubin
c. Glucose
d. α-Keto acids
b. Bilirubin
In the Jaffe reaction, a red-orange chromogen is formed when creatinine
reacts with
a. Aluminum magnesium silicate
b. Creatininase
c. Phosphocreatine
d. Picric acid
d. Picric acid
Creatinine excretion typically
a. Decreases from childhood to middle age
b. Does not vary with age and sex
c. Is higher for females than for males
d. Is highest for adult men aged 18 to 50 years
d. Is highest for adult men aged 18 to 50 years
Use of serum creatinine to calculate GFR
a. Is discouraged because the calculations are complex
b. Is encouraged as a means to identify kidney disease and improve
patient care
c. Requires hospitalization of the patient for specimen collection
d. Requires simultaneous measurement of creatinine in a 24-hour urine
collection
b. Is encouraged as a means to identify kidney disease and improve
patient care