PART 2: Routine examination of urine (week 4) Flashcards
- The ability of proteins to alter the color
reaction without altering the pH - The test area is buffered to a constant low so that the changes in color will reflect the presence and concentration of proteins.
- Test area is more sensitive to albumin than globulin, Bence-Jones protein, or mucoprotein
- Indicator – tetrabromphenol blue: (-) yellow; (+) green then blue
Other indicators used:
- Tetrachlorophenol
- Tetrabromosulfonaphthaelin
Reagent Strip Method
contains more amino groups
to accept H+ than other proteins
Albumin
Reagent Strip Method other indicators used:
- Tetrachlorophenol
- Tetrabromosulfonaphthaelin
1) Highly buffered alkaline urine
2) High specific gravity
3) Quaternary ammonium compounds
False positive
a) Proteins other than albumin
b) Microalbuminuria
False negative
Principle: Precipitation of
protein by heat and coagulation
by chemical agents
Note: Persistent cloudiness indicates protein.
HEAT AND ACETIC ACID
(+)result: precipitation
This is a cold precipitation test because it
doesn’t require heating
3% SULFOSALICYLIC ACID TEST (EXTON’S)
White opaque ring at the zone of contact
- Heller’s ring or heller’s heat or nitric acid test
Light cloudiness to a heavy flocculation
Picric acid test
White ring at the point of contact
Robert’s ring test
Highly alkaline urine in Acid precipitation
tests
False negative
Highly alkaline urine in Rgt strip test
False positive
Quaternary ammonium compounds in Rgt strip
False positive
Radiographic contrast media in rgt strip
No effect
Radiographic contrast media heat and acetic acid test
False positive
SSA +TCA ( nephelometer or photometer)
Precipitation