Chemical Examination of Urine (Reagent Strips | M) Flashcards
Where are reagent strips (in UA) used?
In routine chemical examination
What is the action of reagent strips?
To provide a simple, rapid means for performing medically significant chemical urinalysis of urine
What are the tests (or pads) present in the reagent strip?
1) pH
2) Glucose
3) Blood
4) Urobilinogen
5) Leukocytes
6) Protein
7) Ketones
8) Bilirubin
9) Nitrite
10) Specific gravity
What is the characteristic of reagent strips?
It consists of chemical-impregnated absorbent pads attached to a plastic strip
What is the reaction brought by reagent strips?
A color producing chemical rxn takes place when the absorbent pad comes in contact w/ the urine
How is a color producing chemical rxn produced via the use of reagent strips?
When the absorbent pad comes in contact w/ the urine
How are the color rxns (from the reagent strip) interpreted?
The rxns are interpreted by comparing the color produced on the pad, within the required time frame, w/ the chart supplied by the manufacturer
What should be followed when interpreting the color rxns of reagent strip?
These color rxns should be interpreted within the required time frame, w/ the chart supplied by the manufacturer
What are the 2 major types of reagent strips manufacturer?
1) Multistix (Siemens Healthcare Diagnostics, Deerfield, IN)
2) Chemstrip (Roche Diagnostics, Indianapolis, IN)
What is the form of results (or value) obtained via reagent strip testing?
Semi-quantitative results (or value)
How to report results of reagent strips?
1) Trace
2) 1+
3) 2+
4) 3+
5) 4+
or
1) +
2) ++
3) +++
Are SI units also provided by automated reagent strip readers?
Yes
What is the automated device / machine used to analyze the reagent strip?
Urine strip analyzer
What sx should be used for reagent strip testing?
Well-mixed uncentrifuged urine
What is the process (or steps) of reagent strip technique?
1) Dip the rgnt strip briefly into a well-mixed uncentrifuged urine sx at room temp
2) Remove excess urine by touching the edge of the strip to the container as the strip is withdrawn
3) Blot the edge of the strip horizontally on an absorbent medium
4) Wait the specified length of time for rxns to take place
After dipping the rgnt test strip onto the urine, what should be done?
Remove excess urine by touching the edge of the strip to the container as the strip is withdrawn
What is the orientation when blotting dry the rgnt strip to an absorbent medium (after dipping it to the sx)?
Blot the edge horizontally
After dipping the reagent strip and after blotting it dry, should reading of rxns be done promptly?
No, MT should wait for the specified time for color rxns to take place
What are the errors caused by improper technique?
1) Formed elements such as red and white blood cells sink to the bottom of the sx and will be undetected in an unmixed sx
2) Allowing the strip to remain in the urine for an extended period may cause leaching of rgnts from the pads
3) Excess urine remaining on the strip after its removal from the sx can produce a run-over bet chemicals on adjacent pads, producing distortion of the colors. (Blot the edge of the strip on absorbent paper horizontally)
4) The timing for rxns to take place should be followed
5) For the best semiquantitative results, the manufacturer’s stated time should be followed
6) Always use a good light source for accurate interpretation of color rxns
7) The strip must be held close to the color chart w/out actually being placed on the chart
8) Automated rgnt strip instruments standardize the color interpretation and timing of the rxn
9) Rgnt strips and color charts from diff manufacturers are not interchangeable
10) Sxs that have been refrigerated must be allowed to return to room temp prior to rgnt strip testing
What are exs of formed elements that sink to the bottom of the sx?
1) RBCs
2) WBCs
Are formed elements detected in an unmixed sx?
No
What is the result if the strip is allowed to remain in the urine for an extended period of time?
It may cause leaching of rgnts from the pads
What is the result if there is presence of excess urine remaining on the strip (after removal from the sx)?
It can produce a run-over bet chemicals on adjacent pads, producing distortion of the colors
What is the timing for rxns for pH?
Immediate rxn
What is the timing for rxns for LE?
120 secs
What is the recommendation of manufacturer’s for the time for reading the results (for optimum rxns; for most? tests)?
Manufacturer’s recommend that rxns can be read bet 60 and 120 secs
What is the recommendation of the manufacturers for the time for optimum rxn of LE?
120 secs
What is essential for accurate interpretation of color rxns?
A good light source
How are the color rxns read?
The strip must be held close to the color chart w/out actually being placed on the chart
What is the action of automated rgnt strip instruments?
It standardizes the color interpretation and timing of the rxn
Are rgnt strips and color charts from diff manufacturers interchangeable?
No
What must be done for refrigerated sxs?
It must be allowed to return to room temp
Why do refrigerated sxs must be returned to room temp prior to rgnt strip testing?
Because the enzymatic rxns on the strips are temp dependent
Reagent strips must be protected from deterioration caused by what?
1) Moisture
2) Volatile chemicals
3) Heat
4) Light
How are rgnt strips (chemstrip?) packaged?
These are packaged in opaque containers w/ a dessicant