CHEMICAL EXAM prt.1 Flashcards
The _________is performed using reagent strips, which provide a simple, rapid, and medically significant analysis of urine composition.
chemical examination of urine
________ contain chemically treated test pads that react with specific substances in urine, producing color changes that indicate the presence and approximate concentration of these substances.
reagent strips
Reagent strips are commercially available under various brands, with the most common being:
• Multistix (manufactured by Siemens)
• Chemstrip (manufactured by Roche)
STORAGE CONDITIONS
• Must be stored at ________ to prevent degradation of reagents.
room temperature (RT) below 30°C
Additional
Storage:
• Should be protected from (3) as exposure can affect the accuracy of test results.
• Containers should be ______ immediately after removing a strip to prevent humidity exposure.
moisture, heat, and direct sunlight
tightly closed
First thing to do before starting analysis??
• Reagent strips should be checked for_______ before use.
• _______ strips must not be used, as they can lead to inaccurate results.
discoloration, contamination, or any signs of deterioration
Expired or damaged strips
______BEFORE USE!!!
VISUAL INSPECTION
are used for standardized, objective, and more accurate readings.
These devices eliminate subjective errors associated with visual interpretation.
automated reagent strip readers
PRINCIPLE OF AUTOMATED STRIP READERS
Automated readers use “______”, which is a spectrophotometric measurement of light reflection from the test pads.
Reflectance Photometry
Automated strip readers
Principle:
Light reflection from test pads decreases in proportion to the intensity of color change.
4-Parameter Strip (Basic Urine Test)
+ READING TIME
Glucose - 30 seconds
pH - 60 seconds
Specific Gravity - 45 seconds
Protein - 60 seconds
11-Parameter Strip (Comprehensive Urine Test)
Parameter Reading Time
Leukocytes 120 seconds
Nitrite 60 seconds
Urobilinogen 60 seconds
Protein 60 seconds
pH 60 seconds
Blood 60 seconds
Specific Gravity 45 seconds
Ascorbate 40 seconds
Ketone 40 seconds
Bilirubin 30 seconds
Glucose 30 seconds
GLUCOSE (Reading Time:__seconds)
• Principle:
30 seconds
Double Sequential Enzyme Reaction
BILIRUBIN
• Principle:
Diazo reaction
KETONES
• Principle:
Sodium nitroprusside rn (Legal’s Test)
SG
• Principle:
pKa change of a polyelectrolyte
PROTEIN
• Principle:
Protein (Sorensen’s) error of indicators
pH
• Principle:
Double indicator system
BLOOD
• Principle:
Pseudoperoxidase activity of hemoglobin
UROBILINOGEN
• Principle:
Ehrlich reaction
NITRITE
• Principle:
Greiss reaction
LEUKOCYTE
• Principle:
Leukocyte esterase
GLUCOSE
Positive Color
*Green/Blue to Brown
BILIRUBIN
Positive Color
Tan or Pink to Violet
KETONES
Positive Color
Purple
SG
Positive Color
Blue(1.000) to Yellow (1.030)
PROTEIN
Positive Color
Blue
pH
Positive Color
Orange(5.0) to Blue(9.0)
BLOOD
Positive Color
Uniform green/blue (Hgb/Mb)
Speckled/spotted (intact RBCs)
UROBILINOGEN
Positive Color
Red/ Pink
NITRITE
Positive Color
Uniform Pink
LEUKOCYTE
Positive Color
Purple
