2.3.2 Nonprotein Nitrogen Compounds (Creatinine) Flashcards
Creatinine comprises ____ of total NPN
5%
Creatinine is formed from ______ in the muscles and excreted into plasma at a constant rate
Creatine
The concentration of creatinine is inversely related to GFR (Glomerular filtration rate)
T or F
T
Chemical Method for Creatinine?
a. Jaffe method
b. Phophotungstic Acid method
c. Fearon Method
a
Jaffe method is a colorimetric, endpoint and non-specific
T or F
T
Since Jaffe method is non-specific, Other components in plasma may cause False _________ in absorbance
Increase
Color of Jaffe method for creatinine?
a. Red
b. Orange
c. Red-Orange
c
Techniques to improve specificity of Jaffe reaction are:
- Kinetic: Timed rate reaction
- Use of adsorbents
T or F
T
All of the following are adsorbent used to improve the specificity of Jaffe reaction except:
a. Sodium aluminum silicate
b. Magnesium aluminum silicate
c. Calcium aluminum silicate
d. None of the above
C
Also known as Lloyd’s adsorbent
a. Sodium aluminum silicate
b. Magnesium aluminum silicate
a
Also known as Fuller’s earth adsorbent
a. Sodium aluminum silicate
b. Magnesium aluminum silicate
b
Reagent for Jaffe Method?
a. Alkaline picrate
b. Phenol
c. Heparin sulfate-Mn
d. Creatinase
a
Enzymatic method for Creatinine:
Creatiniase-POD coupled
T or F
T
What is the Product of Creatine + H2O (Creatinase)?
a. Sarcosine
b. H2O2
c. Oxidized chromogen
d. Pyruvate
a
Sarcosine + O2 -______-> CH2O + Glycine + H2O2
Sarcosine Oxidase
Creatine + ATP -______-> Creatine phosphate + ADP
Creatine Kinase
ADP + Phosphenolypyruvate -______-> Pyruvate + ATP
Pyruvate kinase
Pyruvate + NADPH -______-> Lactate + NAD
Lactate dehydrogenase
Reference interval for Creatinine:
Male: 0.9 - 1.3 mg/dL
Female: 0.6 - 1.1 mg/dL
a. Jaffe
b. Enzymatic
a
Reference interval for Creatinine:
Male: 0.6 - 1.1 mg/dL
Female: 0.5 - 0.8 mg/dL
a. Jaffe
b. Enzymatic
b
BUN/Creatinine Ratio
10-20:1 normal ratio
Creatinine clearance (C) =
(UV/P) x (1.73/A)
Reference interval for Creatinine:
Male: 85-125 mL/min
Female: 75-115 mL/min
T or F
T
NOTE: Formula for Cockcroft-Gault formula
C = (140 – age x weight in kg)/ (72 𝑥 𝑠𝑒𝑟𝑢𝑚 𝑐𝑟𝑒𝑎𝑡𝑖𝑛𝑖𝑛𝑒(𝑚𝑔/𝑑𝐿))
x 0.85 if F
The old version of MDRM has 4 variables while the new ones has 6
T or F
F
Baligtad value
Old: Serum creatinine, Age,
Race, Gender, BUN, and Albumin
New: Serum Creatinine, Age,
Race, and Gender
CKD-EPI Formula: Serum
Creatinine, Age, Race, and Gender
T or F
T
Similar to new MDRD formlua
4 variables;es are used which is taken into consideration when estimating GFR using Cockcroft-Gault formula?
Age
Weight
Serum Creatinine
Gender
If BUN/Creatinine ratio > 20:1 with N creatinine:
Bun is high, the ratio is high
T or F
T
Consistent with Pre-renal azotemia
If BUN/Creatinine ratio > 20:1 with ↑ creatinine:
Case of either_____ or post-renal azotemia
renal
if BUN/Creatinine ratio < 10:1
Ratio is low, most likely Bun is low
Due to repeated dialysis, liver disease and low protein diet
T or F
T
Decreased creatinine clearance is due to impaired _____ function
Renal
Decreased creatinine clearance is associated with:
Blood vol.:________
Renal Blood flow:______
GFR:_______
All decrease
GFR is dependent on the RBF, and RBF is dependent on BV
T or F
T
