NPNs

Question 1

Which non protein nitrogen has the highest plasma concentration? a ammonia b creatinine c urea d uric acid

Answer 1

Urea

Question 2

Arrange plasma NPN from most to least concentrated? a urea amino acid uric acid creatinine creatine ammonia b creatinine urea ammonia uric acid c urea uric acid amino acid creatinine ammonia d ammonia creatine creatinine uric acid urea

Answer 2

Urea amino acid uric acid creatinine creatine ammonia

Question 3

BUN is considered what type of term? a modern b enzymatic c older traditional d calculated

Answer 3

Older traditional

Question 4

Urea is the major end product of what metabolism? a lipid b carbohydrate c protein and amino acid d nucleic acid

Answer 4

Protein and amino acid

Question 5

Detoxified ammonia produces what compound? a creatinine b urea c uric acid d glutamine

Answer 5

Urea

Question 6

Urea is filtered in which structure? a tubules b loop of henle c glomerulus d collecting duct

Answer 6

Glomerulus

Question 7

Less than what percent of urea is reabsorbed? a 25 b 40 c 50 d 75

Answer 7

50

Question 8

Creatinine undergoes which renal process? a filtration and reabsorption b secretion only c filtration and secretion d reabsorption only

Answer 8

Filtration and secretion

Question 9

Blood contains more of which analyte? a creatinine b ammonia c urea d uric acid

Answer 9

Urea

Question 10

Which metabolite elevates first in kidney disease? a creatinine b ammonia c uric acid d urea

Answer 10

Urea

Question 11

Which affects BUN concentration? a protein catabolism b diet c kidney status d all of the choices

Answer 11

All of the choices

Question 12

CLINICAL APPLICATIONS OF UREA

Question 13

Urea is used to evaluate what organ function? a liver b kidney c heart d pancreas

Answer 13

Renal function

Question 14

Urea is used to assess what physiologic state? a oxygenation b hydration c acid base d glucose status

Answer 14

Hydration

Question 15

Urea is used to determine what balance? a electrolyte b nitrogen c water d acid base

Answer 15

Nitrogen balance

Question 16

Which condition increases BUN? a pregnancy b celiac disease c dehydration d repeated dialysis

Answer 16

Dehydration

Question 17

Burns increase BUN due to what process? a infection b inflammation c hemorrhage d obstruction

Answer 17

Inflammation

Question 18

Which diet increases BUN? a low fat b low protein c high protein d vegetarian

Answer 18

High protein

Question 19

Which medication increases BUN? a insulin b antibiotics c steroids d antihistamines

Answer 19

Steroids

Question 20

Which condition causes decreased BUN? a dehydration b chronic renal disease c pregnancy d stress

Answer 20

Pregnancy

Question 21

Severe liver disease causes what BUN change? a increase b no change c decrease d fluctuation

Answer 21

Decrease

Question 22

Acute tubular necrosis causes what BUN effect? a increase b decrease c normal d variable

Answer 22

Decrease

Question 23

Which anticoagulant should be avoided due to urease inhibition? a heparin b EDTA c sodium fluoride d oxalate

Answer 23

Sodium fluoride

Question 24

Bacterial contamination causes error due to what property? a oxidase positive b catalase positive c urease positive d fermentative

Answer 24

Urease positive

Question 25

Diacetyl monoxime method produces what color derivative? a blue b green c yellow diazine d red orange

Answer 25

Yellow diazine

Question 26

Most frequently used urea method is what type? a chemical b direct enzymatic c indirect enzymatic d potentiometric

Answer 26

Indirect enzymatic

Question 27

Indirect urea method measures which analyte? a urea b carbon dioxide c ammonia d nitrogen

Answer 27

Ammonia

Question 28

What enzyme source is used in urease method? a bacteria b fungi c jack beans d liver

Answer 28

Jack beans

Question 29

Which reagent is used to measure ammonia? a Nessler b Berthelot c Biuret d Lowry

Answer 29

Berthelot

Question 30

Coupled urease and GLD method is also known as what? a endpoint b colorimetric c kinetic d titrimetric

Answer 30

Kinetic

Question 31

Urea urease method measures what change? a absorbance b conductivity c pH d turbidity

Answer 31

pH

Question 32

Electrode method measures what property? a voltage b absorbance c conductivity d fluorescence

Answer 32

Conductivity

Question 33

What is the reference method for urea? a Jaffe b Berthelot c IDMS d GLDH

Answer 33

Isotope dilution mass spectrometry

Question 34

What factor converts BUN to urea? a 1.14 b 1.86 c 2.14 d 3.00

Answer 34

2.14

Question 35

Creatinine is synthesized in which organ? a kidney b muscle c liver d pancreas

Answer 35

Liver

Question 36

Which amino acids form creatine? a alanine serine cysteine b arginine glycine methionine c valine leucine isoleucine d glycine glutamate lysine

Answer 36

Arginine glycine methionine

Question 37

Creatinine is the end product of what metabolism? a lipid b carbohydrate c muscle d protein

Answer 37

Muscle

Question 38

Creatinine is affected by protein diet? a yes b no c slightly d only in disease

Answer 38

No

Question 39

Creatinine is excreted at what rate? a variable b diet dependent c constant d intermittent

Answer 39

Constant

Question 40

Most commonly used test to monitor renal function? a BUN b ammonia c creatinine d uric acid

Answer 40

Creatinine

Question 41

BUN creatinine ratio normal range? a 5 to 10 b 10 to 20 c 20 to 30 d 30 to 40

Answer 41

10 to 20

Question 42

Creatinine is difficult to remove by what process? a filtration b secretion c dialysis d excretion

Answer 42

Dialysis

Question 43

Jaffe reaction forms what colored complex? a blue violet b yellow diazine c red orange d green

Answer 43

Red orange

Question 44

Jaffe reaction uses which reagent? a biuret b picric acid c Nessler d Berthelot

Answer 44

Picric acid

Question 45

Which interferes with Jaffe reaction? a sodium b acetoacetate c calcium d potassium

Answer 45

Acetoacetate and: glucose, acetone, pyruvate, ascorbate (AGAPA)

Question 46

Most accurate Jaffe modification uses what reagents? a urease and GLD b Fuller earth and Lloyd reagent c Berthelot and Nessler d chromogen only

Answer 46

Fuller earth and Lloyd reagent

Question 47

Disadvantage of this method? a low accuracy b low specificity c time consuming d expensive reagents

Answer 47

Time consuming

Question 48

Kinetic Jaffe method requires what setup? a manual titration b incubation only c automated equipment d centrifugation

Answer 48

Automated equipment

Question 49

Advantage of kinetic Jaffe method? a expensive b slow c rapid and easy d highly manual

Answer 49

Rapid and easy

Question 50

Which enzyme converts creatinine to creatine? a creatinase b creatininase c urease d oxidase

Answer 50

Creatininase

Question 51

Sarcosine oxidase produces what analyte measured? a ammonia b hydrogen peroxide c carbon dioxide d urea

Answer 51

Hydrogen peroxide

Question 52

Final colored product is formed using what enzyme? a oxidase b catalase c peroxidase d dehydrogenase

Answer 52

Peroxidase

Question 53

Azotemia is defined as elevation of what? a creatinine only b urea only c urea and creatinine d ammonia only

Answer 53

Urea and creatinine

Question 54

Pre renal azotemia is caused by what primary factor? a obstruction b nephron damage c decreased blood flow d infection

Answer 54

Decreased blood flow

Question 55

Renal azotemia is characterized by what urea creatinine pattern? a both normal b urea high creatinine low c urea striking high creatinine slow rising d creatinine only elevated

Answer 55

Striking high urea slowly rising creatinine

Question 56

Post renal azotemia is caused by what? a dehydration b stone c fever d stress

Answer 56

Stone

Question 57

Uremia is azotemia with what condition? a dehydration b obstruction c renal damage d liver failure

Answer 57

Renal damage

Question 58

Uremia causes what electrolyte imbalance? a hypokalemia b hypernatremia c hyperkalemia d hypocalcemia

Answer 58

Hyperkalemia

Question 59

Burr cells are seen in which condition? a anemia b leukemia c uremia d liver disease

Answer 59

Uremia

Question 60

Ammoniacal breath is associated with what condition? a ketoacidosis b uremia c sepsis d pneumonia

Answer 60

Uremia

Question 61

Which purines are catabolized from DNA & RNA? a. Adenosine b. Guanine c. Cytosine d. Thymine

Answer 61

a b

Question 62

Excess purine is converted into which compounds? a. Hypoxanthine b. Guanine c. Adenosine d. Uracil

Answer 62

a b

Question 63

What enzyme allows purines to be returned to purine metabolism? a. HGPRT b. Uricase c. Allopurinol d. Phosphotungstic acid

Answer 63

a

Question 64

Hypoxanthine and guanine are converted into which substance? a. Allantoin b. Uric acid c. MSU d. Tungsten blue

Answer 64

b

Question 65

Uric acid binds with which element to form monosodium urates (MSU)? a. Sodium b. Potassium c. Calcium d. Magnesium

Answer 65

a

Question 66

What percentage of uric acid exists as monosodium urates in the kidneys? a. 80% b. 95% c. 50% d. 100%

Answer 66

b

Question 67

How much uric acid is reabsorbed in the proximal tubule? a. 50-60% b. 75% c. 98-99% d. 100%

Answer 67

c

Question 68

What fraction of uric acid is excreted in urine? a. 2% b. 10% c. 25% d. 50%

Answer 68

a

Question 69

Which body system also excretes some uric acid? a. Respiratory b. Gastrointestinal c. Nervous d. Muscular

Answer 69

b

Question 70

What condition occurs when uric acid is insoluble and deposits in joints? a. Hyperuricemia b. Gout c. Lesch-Nyhan syndrome d. Fanconi’s syndrome

Answer 70

b

Question 71

Which of the following diseases is associated with increased nuclear metabolism leading to hyperuricemia? a. Leukemia b. Hemolytic disease c. Lymphoma d. All of the above

Answer 71

d

Question 72

Lesch-Nyhan syndrome is caused by deficiency of which enzyme? a. Uricase b. HGPRT c. Allopurinol d. Phosphotungstic acid

Answer 72

b

Question 73

Lesch-Nyhan syndrome follows which inheritance pattern? a. Autosomal dominant b. Autosomal recessive c. X-linked d. Mitochondrial

Answer 73

c

Question 74

What symptom is seen in children with small renal tracts due to uric acid? a. Hematuria b. Hypertension c. Proteinuria d. Hyperglycemia

Answer 74

a

Question 75

Chronic renal disease leads to hyperuricemia due to what mechanism? a. Increased GFR b. Reduced GFR and tubular secretion c. Increased liver metabolism d. Decreased protein intake

Answer 75

b

Question 76

Hyperuricemia with urinary uric acid >10 mg/dL can lead to what complication? a. Kidney stones b. Liver failure c. Hypertension d. Diabetes

Answer 76

a

Question 77

Which of the following is NOT a cause of hyperuricemia? a. Toxemia of pregnancy b. Ethanol c. Lactic acidosis d. Fanconi’s syndrome

Answer 77

d

Question 78

Which hormonal problem can cause hyperuricemia? a. Menopause b. Diabetes c. Hypothyroidism d. Hyperthyroidism

Answer 78

a

Question 79

Hypouricemia can be caused by which tubular defect? a. Fanconi’s syndrome b. Lesch-Nyhan syndrome c. Polycythemia d. Megaloblastic anemia

Answer 79

a

Question 80

Which disease is associated with hypouricemia due to liver damage? a. Wilson’s disease b. Severe liver disease c. Hodgkin’s disease d. All of the above

Answer 80

d

Question 81

Which chemotherapy drugs can cause hypouricemia? a. 6-mercaptopurine b. Azathioprine c. Allopurinol d. Both a and b

Answer 81

d

Question 82

What is the cause of gout symptoms? a. WBCs consuming uric acid in joints b. Excess sodium c. Tubular damage d. Phosphotungstic acid

Answer 82

a

Question 83

Fasting is required for uric acid measurement? a. Yes b. No c. Only in children d. Only in adults

Answer 83

b

Question 84

Which sample types are suitable for uric acid determination? a. Heparinized plasma b. Serum c. Urine d. All of the above

Answer 84

d

Question 85

Which anticoagulants should be avoided in uricase studies? a. EDTA b. Fluoride c. Heparin d. Both a and b

Answer 85

d

Question 86

How long is uric acid stable at room temperature in serum or urine? a. 1 day b. 2 days c. 3 days d. 7 days

Answer 86

c

Question 87

Urine collection for uric acid should be at which pH? a. 6 b. 7 c. 8 d. 5

Answer 87

c

Question 88

Which method of uric acid determination is chemical and lacks specificity? a. Caraway method b. Uricase method c. Coupled enzyme method d. Mass spectrometry

Answer 88

a

Question 89

The principle of uricase method involves conversion of uric acid into what? a. MSU b. Allantoin c. Tungsten blue d. Chromogen

Answer 89

b

Question 90

Peak absorbance of uric acid is measured at which wavelength? a. 293 nm b. 250 nm c. 350 nm d. 300 nm

Answer 90

a

Question 91

In the uricase coupled enzyme method, H2O2 reacts with what to produce a measurable product? a. Uric acid b. Chromogen c. Allantoin d. MSU

Answer 91

b

Question 92

Which method is considered the reference method for uric acid determination? a. Caraway b. Uricase c. Coupled enzyme d. Isotope dilution mass spectrometry

Answer 92

d