NPN

Question 1

Most abundant NPN in the blood

Answer 1

Urea

Question 2

Take Note!

Answer 2

For urea analysis, avoid using sodium citrate and sodium fluoride additives for plasma

Question 3

Urea conversion factor

Answer 3

0.357

Question 4

BUN to urea conversion factor

Answer 4

2.14

Question 5

Reference method for urea analysis

Answer 5

IDMS

Question 6

Fearon Reaction produces what color by diacetyl monoxime?

Answer 6

Pink

Question 7

Fearon Reaction produces blue color by?

Answer 7

Alkaline (hypochlorite or phenol)

Question 8

Stage of Increased Concentration

Congestive Heart Failure
Shock, hemorrhage
Increased protein metabolism
High protein diet

Answer 8

Pre-Renal

Question 9

Stage of Increased Concentration

Acute and chronic renal disease

Answer 9

Renal

Question 10

Stage of Increased Concentration

Urinary Tract Obstruction

Answer 10

Post-renal

Question 11

Decreased Concentration of Urea happens during

Answer 11

Low protein intake
Severe vomiting and diarrhea
Liver disease
Pregnancy

Question 12

Urea to Creatinine Ratio

Answer 12

10:1 or 20:1

Question 13

Increased urea, normal creatinine

Answer 13

Pre-Renal

Question 14

Increased creatinine

Answer 14

Renal or Post-Renal

Question 15

Decreased both

Answer 15

Post-Renal

Question 16

Second most abundant NPN in the blood

Answer 16

Uric Acid

Question 17

Take Note for Uric Acid!

Answer 17

Avoid icteric samples (peroxidases)

Do not use EDTA and sodium fluoride
anticoagulants/additives (inhibits uricase)

Use heparin for plasma samples (preferably red top)

Bilirubin and ascorbic acid destroys peroxidase enzyme

Question 18

Conversion Factor for Uric Acid

Answer 18

0.0595

Question 19

Uric acid + phosphotungstic acid – allantoin +
tungsten blue

Answer 19

Caraway Method

Question 20

Decreased Concentration of Uric Acid occurs during

Answer 20

Liver disease
Defective tubular reabsorption (Fanconi)
Chemotherapy (azathioprine/6-mercaptopurine)
Overtreatment with allopurinol

Question 21

Product of muscle contraction and energy (ATP) usage

Answer 21

Creatinine / Creatine

Question 22

Amino Acid Components of Creatinine

Answer 22

Arginine
Glycine
Methionine

Question 23

Conversion Factor of Creatinine

Answer 23

88.4

Question 24

Take Note for Creatinine!

Answer 24

Ascorbic acid, glucose and alpha ketoacids may affect Jaffe reaction (creatinine)

Question 25

Drug Interferences for Jaffe

Answer 25

Cephalosporin Dopamine

Question 26

Drug Interferences for Enzymatic

Answer 26

Lidocaine Dopamine

Question 27

Creatinine + Picric acid; Mixture of Reagent A and B – alkaline picrate; red-orange complex (red tautomer)

Answer 27

Jaffe Method

Question 28

Used to isolate creatinine from the sample

Answer 28

Fuller’s earth/Aluminum magnesium silicate Lloyd’s reagent/sodium aluminum silicate

Question 29

Creatininase-Hydrogen Peroxide Creatinine is converted into creatine via?

Answer 29

Creatininase

Question 30

Creatininase-Hydrogen Peroxide Creatine is converted into sarcosine and urea via?

Answer 30

Creatine amidinohydrolase

Question 31

Creatininase-Hydrogen Peroxide Sarcosine is converted into glycine, formaldehyde and hydrogen peroxide via?

Answer 31

Sarcosine oxidase

Question 32

Creatininase-Creatine Kinase Creatine is converted into creatine phosphate and ADP via?

Answer 32

Creatine kinase

Question 33

Creatininase-Creatine Kinase ADP and Phosphoenolpyruvate is converted into pyruvate and ATP via?

Answer 33

Pyruvate kinase

Question 34

Creatininase-Creatine Kinase Pyruvate and NADH is converted into Lactate and NAD via?

Answer 34

Lactate Dehydrogenase

Question 35

Product of protein metabolism → converted immediately to urea by the liver

Answer 35

Ammonia

Question 36

Take Note for Ammonia!

Answer 36

Used EDTA or Heparin anticoagulants Extracted specimen should be placed on ice container immediately Plasma for ammonia analysis is stable at -20oC for several days

Question 37

Ammonia MOA: Microdiffusion chamber; Blood gas determination

Answer 37

Conway

Question 38

Ammonia MOA: Glutamate dehydrogenase (urease method) – decreasing absorbance (NADH to NAD)

Answer 38

Enzymatic Method

Question 39

Ammonia MOA: Bromphenol blue (intense blue in alkaline environment of ammonia)

Answer 39

Dry Slide Method

Question 40

Creatinine is endogenous, synthesized by the body at constant rate (muscle mass), and majority is cleared by renal filtration; It is the relationship between urine and serum creatinine

Answer 40

Creatinine Clearance

Question 41

Low molecular weight protein produced by all tissues; Filtered and metabolized by the proximal convoluted tubules at fixed rate

Answer 41

Cystatin C

Question 42

Assess renal transplant rejection; Also increased in myeloproliferative and lymphoproliferative disorders

Answer 42

Beta-2-Microglobulin

Question 43

May causes acute renal failure in patients with rhabdomyolysis

Answer 43

Myoglobin

Question 44

Presence of protein in the urine

Answer 44

Urinalysis and Microalbuminuria

Question 45

Protein produced by neutrophils and epithelial cells; Early marker of acute kidney injury; Upregulation of genes in renal ischemia, tubule injury and nephrotoxicity

Answer 45

Neutrophil Gelatinase-Associated Lipocalin (NGAL)

Question 46

Take Note for Cystatin C

Answer 46

Cystatin C – high within-subject variation (early detection) Creatinine – high between subject variation (for monitoring purposes)

Question 47

Measured by urine or blood; Secretory ability – kidney must excrete since it is foreign substance

Answer 47

Phensulfonthalein Test

Question 48

Concentrating ability of renal tubules; First morning – high SG, high concentration; Low SG, low concentration

Answer 48

Urine Specific Gravity