(26) RA VICTORINO Flashcards

1
Q

Which one of the following is not an NPN substance?

a. Allantoin
b. Ammonia
c. Creatinine
d. Urea

A

a. Allantoin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which compound constitutes nearly half of the NPN substances in the blood?
a. Ammonia
b. Creatine
c. Urea
d. Uric acid

A

c. Urea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

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

A

d. 19.3 mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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

A

b. Lithium heparin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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

A

b. Enzymatic reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Elevated blood urea concentration is termed
a. Azotemia
b. BUN
c. Uremia
d. Uremic syndrome

A

a. Azotemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Prerenal azotemia is caused by
a. Acute renal failure
b. Chronic renal failure
c. Congestive heart failure
d. Urinary tract obstruction

A

c. Congestive heart failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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

A

d. Urinary tract obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Uric acid is the final product of
a. Allantoin metabolism
b. Amino acid metabolism
c. Purine metabolism
d. The urea cycle

A

c. Purine metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

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

a. Assay interference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which condition is not associated with elevated plasma uric acid
concentration?
a. Allopurinol overtreatment
b. Gout
c. Lesch-Nyhan syndrome
d. Renal disease

A

a. Allopurinol overtreatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Complete deficiency of hypoxanthine–guanine phosphoribosyltransferase
results in which disease?
a. Allantoinism
b. Glycogen storage disease
c. Lesch-Nyhan syndrome
d. Megaloblastic anemia

A

c. Lesch-Nyhan syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A

b. Formation of renal calculi composed of uric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

d. Uric acid 9.1 mg/dL; gout

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

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.

A

c. Creatinine is formed from creatine and creatine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

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

A

b. Bilirubin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

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

A

d. Picric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

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

A

d. Is highest for adult men aged 18 to 50 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

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

A

b. Is encouraged as a means to identify kidney disease and improve
patient care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which factor must be considered for calculation of creatinine clearance using
the MDRD equation?

a. Certification of body mass index
b. Documentation of specimen collection time
c. Identification of ethnicity
d. Verification that the patient was fasting

A

c. Identification of ethnicity

21
Q

Which situation would be expected to falsely increase measured blood
ammonia concentration?

a. The patient smoked two cigarettes 15 minutes prior to phlebotomy.
b. The patient was fasting for 8 hours before blood collection.
c. The patient ate a steak dinner the night before the specimen was
collected.

A

a. The patient smoked two cigarettes 15 minutes prior to phlebotomy.

22
Q

Although arterial blood is the recommended specimen for determination of this analyte, it is seldom used.

a. Ammonia
b. Creatine
c. Urea
d. Uric acid

A

a. Ammonia

23
Q

Toxic effects of elevated blood ammonia concentration include

a. Decreased renal function
b. Hemorrhage and dehydration
c. Mental status changes and coma
d. Pain and inflammation of peripheral joints

A

a. Decreased renal function

24
Q

Ammonia concentrations are measured to evaluate

a. Acid–base status
b. Glomerular filtration
c. Hepatic encephalopathy
d. Renal failure

A

c. Hepatic encephalopathy

25
Q

Ammonia concentration correlates with disease severity and prognosis for

a. Astrocytosis
b. Inherited deficiencies of urea cycle enzymes
c. Neurological deterioration
d. Reye’s syndrome

A

b. Inherited deficiencies of urea cycle enzymes

26
Q
  • The NPN compound present in highest concentration in the blood
  • major excretory product of protein metabolism.
A

urea

27
Q

Following synthesis in the
___, urea is carried in the blood to the ___, where it is readily filtered from
the plasma by the ___.

A

Following synthesis in the
liver, urea is carried in the blood to the kidney, where it is readily filtered from
the plasma by the glomerulus.

28
Q

Measurement of urea is used to evaluate

A
  • renal function,
  • to assess hydration
    status,
  • to determine nitrogen balance,
  • to aid in the diagnosis of renal disease, and
  • to verify adequacy of dialysis
29
Q

catalyzes hydrolysis of urea in the sample

A

urease (urea
amidohydrolase

30
Q

used to refer to urea determination.

A

Blood Urea Nitrogen (BUN)

31
Q

elevated conc. of urea in blood

A

Azotemia

32
Q

Very high plasma urea concentration accompanied by renal failure is called

A

uremia, or the uremic syndrome

33
Q

Reference range of Urea N:

A

Serum or plasma: 6-20 mg/dl
24 hours Urine: 12-20 g/day

34
Q

produced as a waste product of creatine and creatine phosphate.

A

creatinine

35
Q

measure of the amount of creatinine eliminated from the blood by the kidneys per unit time

A

Creatinine Clearance

36
Q

final breakdown product of purine metabolism (adenosine/guanine) in liver

A

uric acid

37
Q

Comes from deamination of amino acids

A

ammonia

38
Q

Reference Method

A

Isotope Dilution Mass Spectrometry

39
Q

urea site of formation

A

liver

40
Q

decreased BUN

A
  • Low protein intake,
  • Severe vomiting and diarrhea,
  • Liver disease and
  • Pregnancy
41
Q

Creatine First Transamidation:

A

Arginine and Glycine

42
Q

Creatine Second Reaction:

A

Methionine

43
Q

increased creatine

A
  • Muscular dystrophy,
  • Poliomyelitis,
  • Hyperthyroidism and
  • Trauma
44
Q

reliable test for renal function because it is relatively independent to protein diet, hydration and protein metabolism

A

serum creatinine

45
Q

Normal Urea Nitrogen/ Creatinine Ratio

A

10:1 – 20:1

46
Q

Gold standard for Glomerular Filtration Rate

A

Inulin (best exogenous substance)

47
Q
  • indirect method to assess GFR
  • mL of cleared plasma creatinine by kidneys per minute
A

Clearance

48
Q

uric acid in plasma

A

monosodium urate