Podcast
Questions and Answers
What is the primary purpose of commercial reagent strips for urine analysis?
What is the primary purpose of commercial reagent strips for urine analysis?
- To determine the volume of urine produced
- To collect urine samples for further examination
- To offer a simple and rapid chemical analysis of urine (correct)
- To provide a method for urine culture
Which of the following tests can be performed using commercial reagent strips?
Which of the following tests can be performed using commercial reagent strips?
- Cholesterol levels
- Sodium levels
- Creatinine levels
- Protein levels (correct)
What does the reaction on a reagent strip depend on when performing a urine analysis?
What does the reaction on a reagent strip depend on when performing a urine analysis?
- The concentration of urine
- The color-producing chemicals on the pads (correct)
- The pH of the urine
- The temperature of the urine sample
How are the results from urine reagent strips interpreted?
How are the results from urine reagent strips interpreted?
What is indicated by a color change on a reagent strip?
What is indicated by a color change on a reagent strip?
What type of values can be reported from a urine analysis using reagent strips?
What type of values can be reported from a urine analysis using reagent strips?
Which of the following reagent types is NOT mentioned as a major type of reagent strip?
Which of the following reagent types is NOT mentioned as a major type of reagent strip?
What is the significance of the different levels such as trace and 4+ in urine analysis?
What is the significance of the different levels such as trace and 4+ in urine analysis?
What should be done if control results during quality control testing are out of range?
What should be done if control results during quality control testing are out of range?
What is the recommended method to prevent runover between chemicals on adjacent pads of a reagent strip?
What is the recommended method to prevent runover between chemicals on adjacent pads of a reagent strip?
What is the usual range for the timing of reaction readings for leukocyte esterase tests?
What is the usual range for the timing of reaction readings for leukocyte esterase tests?
Which of the following is essential for accurate interpretation of color reactions in urinalysis?
Which of the following is essential for accurate interpretation of color reactions in urinalysis?
How often should open bottles of reagent strips be tested with known controls?
How often should open bottles of reagent strips be tested with known controls?
What is the correct first step in using a reagent strip for testing a urine specimen?
What is the correct first step in using a reagent strip for testing a urine specimen?
Which of the following is essential for the proper care of reagent strips?
Which of the following is essential for the proper care of reagent strips?
What can happen if formed elements sink to the bottom of an unmixed specimen?
What can happen if formed elements sink to the bottom of an unmixed specimen?
What should one check for before using a reagent strip?
What should one check for before using a reagent strip?
What is the correct positioning for the reagent strip when comparing it to the color chart?
What is the correct positioning for the reagent strip when comparing it to the color chart?
When comparing the color reaction of the strip pads, what is necessary for optimal results?
When comparing the color reaction of the strip pads, what is necessary for optimal results?
What is the best action to take when starting a new bottle of reagent strips?
What is the best action to take when starting a new bottle of reagent strips?
What should be done immediately before using the reagent strip?
What should be done immediately before using the reagent strip?
In the reagent strip test procedure, how should the specimen be treated before testing if it was refrigerated?
In the reagent strip test procedure, how should the specimen be treated before testing if it was refrigerated?
What should be done if interfering substances are suspected during testing?
What should be done if interfering substances are suspected during testing?
Which statement is false regarding the handling of reagent strips?
Which statement is false regarding the handling of reagent strips?
What is one of the clinical significances of renal tubular acidosis?
What is one of the clinical significances of renal tubular acidosis?
Which of the following can be caused by runover from adjacent pads during urine analysis?
Which of the following can be caused by runover from adjacent pads during urine analysis?
What is the significance of protein determination in urine testing?
What is the significance of protein determination in urine testing?
Which condition is associated with metabolic acidosis?
Which condition is associated with metabolic acidosis?
What does the presence of nitrite and leukocytes in a urine sample suggest?
What does the presence of nitrite and leukocytes in a urine sample suggest?
What can result from defects in renal tubular secretion?
What can result from defects in renal tubular secretion?
What is a consequence of improper handling of urine testing pads?
What is a consequence of improper handling of urine testing pads?
Which type of urine change indicates early renal disease?
Which type of urine change indicates early renal disease?
What must be done to specimens that have been refrigerated before testing with reagent strips?
What must be done to specimens that have been refrigerated before testing with reagent strips?
What is the typical pH range of a healthy individual's first morning urine specimen?
What is the typical pH range of a healthy individual's first morning urine specimen?
Which of the following conditions is NOT associated with acidic urine?
Which of the following conditions is NOT associated with acidic urine?
What is the pH range for normal random urine specimens?
What is the pH range for normal random urine specimens?
Which of the following reagents is used in the double indicator system for pH testing?
Which of the following reagents is used in the double indicator system for pH testing?
What pH level indicates a specimen may have been preserved improperly?
What pH level indicates a specimen may have been preserved improperly?
Which dietary factor is most likely to contribute to alkaline urine?
Which dietary factor is most likely to contribute to alkaline urine?
What is the sensitivity range for pH testing with Multistix?
What is the sensitivity range for pH testing with Multistix?
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Study Notes
Chemical Examination of Urine
- Commercial reagent strips enable rapid chemical analysis of urine for various components.
- Key substances analyzed: pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrite, leukocytes, and specific gravity.
- False negatives can occur for certain tests such as ketones and glucose.
Types of Reagent Strips
- Two major brands: Multistix by Siemens and Chemstrip by Roche Diagnostics.
Reagent Strips Composition and Function
- Strips comprise chemical-impregnated pads attached to a plastic strip.
- A color change occurs upon contact with urine, indicating the presence of certain substances.
- Results are interpreted by comparing the pad color to the manufacturer's color chart.
Reagent Strip Technique
- Briefly dip the strip into a well-mixed, uncentrifuged urine sample at room temperature.
- Remove excess urine and blot the edge of the strip on absorbent material.
- Wait for the specified time before comparing colors to the chart in adequate lighting.
Care of Reagent Strips
- Store in a desiccant with tightly closed containers below 30°C, avoiding freezing and exposure to fumes.
- Use strips before expiration and check for discoloration before use.
Quality Control Measures
- Test open reagent strip bottles with known positive and negative controls daily or as per facility protocol.
- Document control results and reagent lot numbers meticulously.
Errors Due to Improper Technique
- Failure to mix specimens can result in undetected formed elements due to sedimentation.
- Extended immersion may leach chemicals from strips, and excess urine can lead to color runover on pads.
- Timing for readings varies; leukocyte esterase reactions should be read after 120 seconds for accuracy.
Urine pH Overview
- Normal pH for a first morning specimen ranges from 5.0 to 6.0; random specimens range from 4.5 to 8.0.
- A pH greater than 8.5 indicates improper specimen preservation.
Causes of Acid and Alkaline Urine
- Acidic Conditions: Emphysema, diabetes, starvation, dehydration, high-protein diet, certain medications.
- Alkaline Conditions: Hyperventilation, vomiting, renal tubular acidosis, vegetarian diet, bacterial influence.
pH Testing Characteristics
- Utilizes a double indicator system with reagents Methyl red and Bromthymol blue.
- Sensitivity:
- Multistix: pH 5.0–8.5 in 0.5 increments visually.
- Chemstrip: pH 5.0–9.0 in 1.0 increments.
- Potential error sources include adjacent pad runover and bacterial growth.
Clinical Significance of Urine pH
- Indicates respiratory or metabolic acidosis/alkalosis, renal issues, and helps in UTI treatment and crystal identification.
- Important to prevent runover in pH and protein testing areas to ensure accuracy.
Protein Analysis in Urine
- Protein level is a critical indicator of renal disease; proteinuria suggests early renal issues.
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