Reagent Strip Testing Fundamentals and Quality Control
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Questions and Answers

What must laboratory personnel do if the results of a positive control reading do not agree with the published value?

  • Ignore the result as a false positive
  • Report it as an invalid result
  • Accept the result and proceed with testing
  • Resolve the issue through testing additional strips and controls (correct)

    • Which step is essential before testing refrigerated specimens?

  • Mix the specimen well
  • Dip the strip completely into the specimen
  • Let specimens warm to room temperature (correct)
  • Blot the edge of the strip

    • What could cause inaccurate results when using reagent strips?

  • Reading the strips under artificial light
  • Using strips with a longer shelf life
  • Interfering substances and technical carelessness (correct)
  • Using the wrong type of reagent strip

    • Why is it important to understand the principles and significance of urinalysis tests?

    <p>To relate chemical findings to physical and microscopic results</p> Signup and view all the answers

    What is a notable example of reagent strip interference?

    <p>Presence of orange pigment from phenazopyridine compounds</p> Signup and view all the answers

    What should be done with excess urine on the strip after dipping?

    <p>Withdraw the strip against the rim of the container</p> Signup and view all the answers

    What is the recommended way to compare reaction colors on the strip?

    <p>Under a good light source at the specified time</p> Signup and view all the answers

    Which of these actions is NOT recommended when testing with reagent strips?

    <p>Ignore the presence of interfering substances</p> Signup and view all the answers

    What is the primary purpose of the Micral-Test reagent strips?

    <p>To detect albumin in urine</p> Signup and view all the answers

    Which of the following is a common source of false positives in urine testing?

    <p>Highly buffered alkaline urine</p> Signup and view all the answers

    What is the sensitivity range for Multistix albumin detection?

    <p>15 to 30 mg/dL</p> Signup and view all the answers

    How does the ImmunoDip reagent strip detect albumin in the urine?

    <p>Using an immunochromatographic technique</p> Signup and view all the answers

    What is considered significant microalbuminuria?

    <p>30 to 300 mg of albumin in 24 hours</p> Signup and view all the answers

    What type of specimens are recommended for accurate results when using these reagent strips?

    <p>First morning urine specimens</p> Signup and view all the answers

    Which condition is associated with renal issues due to postural proteinuria?

    <p>Diabetic nephropathy</p> Signup and view all the answers

    What can cause a false negative result during albumin testing?

    <p>Presence of other proteins in the urine</p> Signup and view all the answers

    What is the primary purpose of confirmatory tests?

    <p>To confirm the results obtained from tests using different methodologies</p> Signup and view all the answers

    What is the main principle behind traditional reagent strip testing for protein?

    <p>Protein error of indicators</p> Signup and view all the answers

    What happens to the bound conjugates during the albumin testing process?

    <p>They react and move towards an enzyme substrate area</p> Signup and view all the answers

    Which control tests should be performed on new reagents?

    <p>Both positive and negative controls</p> Signup and view all the answers

    What procedure is used for detecting proteins in urine through precipitation?

    <p>Sulfosalicylic acid precipitation test</p> Signup and view all the answers

    Which reagent strip has a higher sensitivity for detecting albumin?

    <p>Chemstrip</p> Signup and view all the answers

    How does the advent of automated strip readers affect the use of confirmatory tests?

    <p>It reduces the need for routine confirmatory tests.</p> Signup and view all the answers

    Which of the following may cause false positives in urine protein tests?

    <p>Strenuous exercise</p> Signup and view all the answers

    What is the typical pH range for normal random urine specimens?

    <p>4.5 to 8.0</p> Signup and view all the answers

    What is the significance of the albumin excretion rate (AER) in microalbuminuria testing?

    <p>It helps determine the severity of proteinuria.</p> Signup and view all the answers

    Which of the following conditions is typically linked to podocyte injury in the glomeruli?

    <p>Amyloidosis</p> Signup and view all the answers

    When should confirmatory tests be performed according to facility protocol?

    <p>When questionable results are obtained</p> Signup and view all the answers

    What is the significance of testing highly pigmented specimens?

    <p>They may necessitate confirmatory testing due to questionable results</p> Signup and view all the answers

    During which phase is increased pressure on the renal vein most concerning?

    <p>In the vertical position</p> Signup and view all the answers

    What pH is typically found in a first morning urine specimen?

    <p>5.0 to 6.0</p> Signup and view all the answers

    Why is it necessary to check the chemical reliability of confirmatory tests?

    <p>To ensure results are valid using positive and negative controls</p> Signup and view all the answers

    What may cause a false-negative result in glucose testing?

    <p>High levels of ascorbic acid</p> Signup and view all the answers

    What is the primary reason for false-negative glucose results?

    <p>Allowing specimens to remain unpreserved at room temperature</p> Signup and view all the answers

    What substance does the copper reduction test primarily measure for glucose?

    <p>Cuprous oxide</p> Signup and view all the answers

    What color indicates a negative result in the copper reduction test?

    <p>Blue</p> Signup and view all the answers

    What can occur at high glucose levels during the copper reduction test?

    <p>Pass through phenomenon</p> Signup and view all the answers

    What temperature condition may affect the sensitivity of glucose measurements?

    <p>Low temperatures</p> Signup and view all the answers

    During the copper reduction test, how should the sample be observed?

    <p>Closely as the reaction occurs</p> Signup and view all the answers

    What color transition occurs in the copper reduction test from no glucose to high glucose levels?

    <p>Blue to orange/red</p> Signup and view all the answers

    Study Notes

    Reagent Strip Testing Fundamentals

    • Reagent strips are designed for ionic concentrations similar to urine for accurate testing.
    • Performance of negative controls must yield negative readings, while positive controls should align with published values.
    • Misleading results may arise from interfering substances, technical errors, and color blindness.
    • Awareness of reagent strip limitations is essential, including specific interferences, such as those caused by phenazopyridine compounds.

    Confirmatory Testing

    • Confirmatory tests utilize different reagents to detect substances with similar or higher sensitivity.
    • Routine confirmatory tests have declined due to improved specificity and sensitivity of modern reagent strips.
    • Non-reagent testing options like tablets and liquid chemicals can be employed for questionable results.
    • Confirmatory tests provide further validation for positive outcomes previously identified by reagent strips.

    Quality Control Measures

    • Open bottles of reagent strips require testing against known positive and negative controls per facility protocols.
    • Control results that fall outside acceptable ranges necessitate further testing to determine accuracy.
    • New reagents and bottles should also be tested against positive and negative controls.
    • Recording control results and reagent lot numbers is important for traceability.

    pH and Urine Characteristics

    • Normal urine pH ranges from 4.5 to 8.0; first morning specimens are typically slightly acidic at pH 5.0 to 6.0.
    • Alkaline urine may occur post-meal, known as the alkaline tide.

    Microalbuminuria Testing Historical Context

    • Detection of microalbuminuria initially involved a 24-hour urine collection and quantitative albumin testing.
    • Significant values were established at 30 to 300 mg in 24 hours or an albumin excretion rate (AER) of 20 to 200 µg/min.

    Reagent Strip Reactions

    • Traditional protein testing uses colorimetric reactions relying on the protein error of indicators, notably albumin.
    • Immunochemical assays, such as Micral-Test and ImmunoDip, provide alternative methods for albumin detection in urine.

    Copper Reduction Test

    • The copper reduction test measures glucose via the ability of glucose to reduce copper sulfate to cuprous oxide.
    • Color changes during the test range from blue (negative) to orange/red (positive), needing careful observation to avoid false negatives (pass-through phenomenon).

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    Description

    Explore the essential concepts behind reagent strip testing, including the importance of negative and positive controls. Understand the relevance of confirmatory tests and various quality control measures to ensure accurate testing results. The quiz covers the limitations and potential interferences related to reagent strips.

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