NPNs

Question 1

The concentration of nitrogen-containing compounds
in this protein-free filtrate was quantified spectrophotometrically by converting
nitrogen to ammonia and subsequent reaction with ________ reagent to produce a yellow color

Answer 1

Nessler’s reagent (K2[HgI4)

Question 2

Most abundant NPN to least

Answer 2

Urea
Amino acids
Creatinine
Creatine
Ammonia

Question 3

the major excretory product of protein metabolism.

Answer 3

Urea

Question 4

Small quantities of urea

(<10% of the total) are excreted through the:

Answer 4

GI tract & skin

Question 5

Reference method for Urea

Answer 5

isotope dilution mass spectrometry (IDMS)

Question 6

Analytic methods (Urea): Conversion of unionized urea to NH4 & CO2-3 results in increased conductivity

Answer 6

Conductometric

Question 7

Analytic methods (Urea): Enzymatic reaction of NH4 2-oxoglutarate & NADH to form glutamate & NAD+

Answer 7

GLDH-couple enzymatic

Question 8

Normal value of Urea Nitrogen (plasma/serum)

Answer 8

6-20mg/dl

Question 9

Normal value of Urea Nitrogen (urine)

Answer 9

12-20g/d

Question 10

An elevated concentration of urea in the blood is called

Answer 10

azotemia.

Question 11

Very high

plasma urea concentration accompanied by renal failure is called

Answer 11

uremia or the

uremic syndrome.

Question 12

is a result of reduced renal blood flow. Less blood is

delivered to the kidney; consequently, less urea is filtered.

Answer 12

Prerenal azotemia

Question 13

Decreased renal function causes an increase in plasma urea concentration as
a result of compromised urea excretion.

Answer 13

renal azotemia

Question 14

can be due to
obstruction of urine flow anywhere in the urinary tract by renal calculi, tumors
of the bladder or prostate, or severe infection.

Answer 14

Postrenal azotemia

Question 15

The major causes of decreased plasma urea concentration include

Answer 15

low

protein intake and severe liver disease. Pregnancy

Question 16

Urea: Increased
Urea N/C ratio: High
Crea: Normal

Answer 16

Prerenal

Question 17

Urea: Increased
Urea N/C ratio: High
Crea: Increased

Answer 17

Postrenal

Question 18

product of catabolism of the purine nucleic acids.

Answer 18

Uric acid

Question 19

Renal excretion

accounts for about __% of uric acid elimination;

Answer 19

70

Question 20

Nearly all of the uric acid in plasma is present as

Answer 20

monosodium urate.

Question 21

Most other mammals have the ability to

catabolize purines to _______, a more water-soluble end product.

Answer 21

allantoin

Question 22

based on the
oxidation of uric acid in a protein-free filtrate, with subsequent reduction of phosphotungstic acid in alkaline solution to tungsten blue. The method lacks
specificity.

Answer 22

Caraway method

Question 23

Reference method for URIC ACID

Answer 23

IDMS

Question 24

Drugs such as

__________ have been shown to increase values for uric acid.

Answer 24

salicylates and thiazides

Question 25

may falsely | decrease results obtained by peroxidase methods.

Answer 25

High bilirubin

Question 26

should not be used | for specimens that will be tested by a uricase method.

Answer 26

EDTA/Fluoride additives

Question 27

a disease found primarily in men and is usually first diagnosed between 30 and 50 years of age. Affected individuals have pain and inflammation of the joints caused by precipitation of sodium urates.

Answer 27

Gout

Question 28

result of overproduction of uric acid, although hyperuricemia may be exacerbated by a purine-rich diet, drugs, and alcohol.

Answer 28

hyperuricemia

Question 29

which inhibits xanthine oxidase (EC | 1.1.3.22), an enzyme in the uric acid synthesis pathway, is used for treatment.

Answer 29

Allopurinol

Question 30

TRUE/FALSE: Patients with hemolytic or megaloblastic anemia may exhibit elevated uric acid concentration.

Answer 30

TRUE

Question 31

X-linked genetic disorder (seen only in males) caused by the complete deficiency of hypoxanthine–guanine phosphoribosyltransferase (EC 2.4.2.8), an important enzyme in the biosynthesis of purines.

Answer 31

Lesch-Nyhan syndrome

Question 32

Mutations in the first enzyme in the purine synthesis pathway, _______ (EC 2.7.6.1), also cause elevated uric acid concentration.

Answer 32

phosphoribosylpyrophosphate synthetase

Question 33

result of decreased uric acid excretion is a common feature of toxemia of pregnancy (preeclampsia) and lactic acidosis presumably as a result of competition for binding sites in the renal tubules.

Answer 33

Hyperuricemia

Question 34

Liver disease Fanconi syndrome Chemotherapy with azathiprine/6-mercaptopurine Overtreatment with allopurinol

Answer 34

Hypouricemia

Question 35

Plasma | creatinine is _____ related to glomerular filtration rate (GFR)

Answer 35

inversely

Question 36

Creatine is synthesized primarily in the liver from ____ (amino acids)

Answer 36

arginine, glycine, and | methionine.

Question 37

used to determine the sufficiency of kidney function, to determine the severity of kidney damage, and to monitor the progression of kidney disease.

Answer 37

Measurement of creatinine concentration

Question 38

a measure of the amount of creatinine | eliminated from the blood by the kidneys, and GFR are used to gauge renal function

Answer 38

Creatinine clearance (CrCl)

Question 39

Modification | of Diet in Renal Disease (MDRD) equation variables:

Answer 39

serum creatinine concentration, age, gender (sex), and | ethnicity

Question 40

has been developed to calculate | eGFR in the pediatric population.

Answer 40

modified Schwartz equation

Question 41

In this reaction, creatinine reacts with picric | acid in alkaline solution to form a red-orange chromogen.

Answer 41

Jaffe | reaction

Question 42

used routinely despite these problems because it is inexpensive, rapid, and easy to perform.

Answer 42

kinetic Jaffe method

Question 43

Reference method for Creatinine

Answer 43

IDMS

Question 44

may increase creatinine concentration measured by the Jaffe reaction, especially at temperatures above 30°C.

Answer 44

Ascorbate, glucose, α-keto acids, and uric acid

Question 45

May falsely elevate Crea when Jaffe reaction is used

Answer 45

cephalosporin antibiotics

Question 46

causes a positive bias in some enzymatic | methods.

Answer 46

Lidocaine

Question 47

known to affect both enzymatic | and Jaffe methods.

Answer 47

Dopamine

Question 48

Plasma creatinine is a relatively insensitive marker and may not be measurably increased until renal function has deteriorated more than ___%

Answer 48

50

Question 49

produced in the deamination of amino acids during protein metabolism. 5 It is removed from the circulation and converted to urea in the liver.

Answer 49

Ammonia

Question 50

is the most common cause of disturbed ammonia metabolism.

Answer 50

Severe liver disease

Question 51

occurring most commonly in children, is a serious disease that can be fatal. Frequently, the disease is preceded by a viral infection and the administration of aspirin.

Answer 51

Reye's syndrome

Question 52

associated with inherited deficiency of urea cycle | enzymes.

Answer 52

Hyperammonemia