Urine Physical Examination Quiz
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Questions and Answers

What is the primary pigment that gives urine its yellow color?

  • Uroerythrin
  • Urates
  • Urochrome (correct)
  • Urobilin

    • Orange-brown color in urine can be caused by fresh urine.

    False

    What is a common cause of colorless urine?

    Recent fluid consumption

    A dark yellow urine can be caused by __________.

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

    Match the urine clarity conditions with their potential causes:

    <p>Colorless urine = Recent fluid consumption Pale yellow urine = Diabetes mellitus Dark yellow urine = Dehydration Orange-yellow urine = Phenazopyridine</p> Signup and view all the answers

    What is the specific gravity of urine that is considered isosthenuric?

    <p>1.010</p> Signup and view all the answers

    The refractive index does not compare light velocity in air with light velocity in solutions.

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

    A specific gravity lower than 1.002 likely indicates what?

    <p>Diluted urine</p> Signup and view all the answers

    What happens to the pH of urine when the concentration increases?

    <p>It decreases as more hydrogen ions are released.</p> Signup and view all the answers

    What is the time frame for the leukocyte esterase reaction?

    <p>2 minutes</p> Signup and view all the answers

    Which of the following indicators is part of the double indicator system used for pH testing in urine?

    <p>Methyl red</p> Signup and view all the answers

    Which substance can cause a false positive result in the leukocyte esterase test?

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

    What may high levels of nitrite in urine indicate?

    <p>Bacterial contamination</p> Signup and view all the answers

    What is a potential false negative cause for leukocyte esterase testing?

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

    What occurs during the first step of the double sequential enzyme reaction involving glucose oxidase?

    <p>Glucose is oxidized to gluconic acid and hydrogen peroxide</p> Signup and view all the answers

    Which substance is used as a chromogen in the glucose oxidase reaction?

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

    What can lead to a false negative result in glucose testing?

    <p>High alkaline urine with a pH greater than 6.5</p> Signup and view all the answers

    If a urine test shows a positive result for glucose but a false negative interpretation occurs, what could be the source of interference?

    <p>Ascorbic acid</p> Signup and view all the answers

    Which of the following indicates that the specific gravity of urine is high?

    <p>Color change from blue to shades of green</p> Signup and view all the answers

    What type of substances can result in a positive glucose test aside from glucose itself?

    <p>Various non-glucose reducing substances</p> Signup and view all the answers

    Which of the following factors could cause a false positive in glucose testing?

    <p>High concentration of protein in urine</p> Signup and view all the answers

    What is the color range change of the indicator pad due to specific gravity increase?

    <p>From blue to shades of green to yellow</p> Signup and view all the answers

    Which substance can indicate the presence of hematuria when a positive reagent strip is observed?

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

    What is the principle behind the detection of certain components in urine using a chromogen?

    <p>Change in pKa of polyelectrolytes</p> Signup and view all the answers

    What effect does exposure to light have on certain urine specimens?

    <p>Causes pigmented appearance</p> Signup and view all the answers

    What can cause a false positive result when testing for hemoglobin in urine?

    <p>Oxidizing agent use</p> Signup and view all the answers

    Which condition can result in bilirubinuria?

    <p>Cirrhosis of the liver</p> Signup and view all the answers

    What pH change can affect the measurement of polyelectrolyte ionization in urine testing?

    <p>Alkaline medium</p> Signup and view all the answers

    What is indicated by a chromogenic reaction that changes from green to blue during urine testing?

    <p>Presence of hemoglobin</p> Signup and view all the answers

    What level of ascorbic acid in urine can cause a false negative result in testing?

    <p>Greater than 25 mg/dL</p> Signup and view all the answers

    What pH range indicates a normal random sample of urine?

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

    What may cause a false acidic reading in alkaline urine?

    <p>Dilute alkaline run</p> Signup and view all the answers

    Which factor can alter the color of the protein indicator without changing the pH?

    <p>Presence of histiocytes</p> Signup and view all the answers

    What indicates an improperly preserved urine sample?

    <p>pH of 8.5 or higher</p> Signup and view all the answers

    Which of the following is a key component of the protein error of indicator principle?

    <p>Color alteration without changing pH</p> Signup and view all the answers

    What can contribute to elevated protein levels greater than 500 mg/dL in urine?

    <p>Infection or inflammation</p> Signup and view all the answers

    What is a characteristic of bilirubin as a compound?

    <p>It is a product of hemoglobin degradation.</p> Signup and view all the answers

    What limitation is associated with the measurement of bilirubin?

    <p>It only measures direct bilirubin.</p> Signup and view all the answers

    Which time frame is associated with the principle of bilirubin measurement using the diazo reaction?

    <p>30 seconds</p> Signup and view all the answers

    What is the primary principle behind the reaction that detects acetoacetate?

    <p>Sodium nitroprusside reaction.</p> Signup and view all the answers

    Which of the following is a potential false positive for bilirubin tests?

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

    Which intermediate product of fat metabolism is mentioned?

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

    What can lead to false negative results when testing for bilirubin?

    <p>Improper preservation of the specimen.</p> Signup and view all the answers

    What is the color indication for a rise in bilirubin levels in urine?

    <p>Increasing degrees of tan to pink</p> Signup and view all the answers

    Study Notes

    Urine Examination Overview

    • Physical examination of urine includes assessment of color, clarity, specific gravity, and odor.

    Color

    • Urochrome is the yellow pigment responsible for urine color, stemming from endogenous metabolism.
    • Additional pigments include:
      • Uroerythrin: contributes pink color in sediments.
      • Urobilin: an oxidation product imparting an orange-brown color to non-fresh urine.

    Urine Color Interpretation

    • Colorless urine may indicate recent fluid consumption.
    • Pale yellow urine can suggest:
      • Polyuria or diabetes insipidus.
      • Diabetes mellitus.
    • Dark yellow urine is associated with:
      • Dehydration.
      • Vitamin B complex consumption.
      • Presence of bilirubin or certain medications (e.g., acriflavine, nitrofurantoin).
    • Orange-yellow urine can result from medications like phenazopyridine.
    • Yellow-green urine indicates bilirubin oxidation to biliverdin.
    • Green urine is often linked to Pseudomonas infection.
    • Blue-green urine can result from drugs such as amitriptyline or methocarbamol.

    Urine Clarity

    • Clarity refers to transparency and turbidity. Assessed by observing the specimen against a light source.
    • Causes of turbidity can be subdivided:
      • Pathological:
        • Presence of RBCs, WBCs, abnormal crystals, bacteria, or lymph fluid.
      • Nonpathological:
        • Squamous epithelial cells, mucus, amorphous phosphates, semen, and radiographic contrast dye.

    Procedure for Assessing Color and Clarity

    • Use a well-mixed specimen and evaluate through a clear container against a white background with adequate lighting.
    • Maintain consistent volume for accurate assessment.

    Specific Gravity

    • Defined as the density of urine compared to distilled water (SG 1.000).
    • Typical specific gravity ranges from 1.015 to 1.030.
    • Isosthenuric is at 1.010, while hyposthenuric is below this, and hypersthenuric is above.

    Measurement Techniques

    • Refractometer measures urine concentration by assessing the refractive index.
    • Corrections are needed for protein (subtract 0.003) and glucose (subtract 0.004) concentrations in the urine sample.
    • Osmolality measures colligative properties by particle count.
    • Reagent strips assess pKa changes related to ion presence, not larger molecules.

    Odor

    • Fresh urine typically has a faint, aromatic odor.
    • Odor variations can indicate different conditions or substances:
      • Sweet odor may indicate diabetes.
      • Strong ammonia smell can suggest dehydration or infection.

    Glucose Testing

    • The process involves a double sequential enzyme reaction.
    • Reactants include glucose and oxygen, with glucose oxidase producing gluconic acid and hydrogen peroxide.
    • The second reaction uses hydrogen peroxide and a chromogen with peroxidase to yield an oxidized colored chromogen and water.
    • Glucose concentrations are identified as either positive or negative, with the presence of reducing substances impacting results.

    Copper Reduction Interpretation

    • Chromogen indicators include potassium iodide (transitions from green to brown) and tetramethylbenzidine (yellow to green).
    • Negative results may indicate the presence of non-glucose reducing substances or interference from ascorbic acid.
    • Reporting includes negative, trace, and graded positives (1+ to 4+).
    • Time frame for reactions is 30 seconds.

    Specific Gravity (SG) Testing

    • Specific gravity readings reflect urine concentration, shifting from blue in alkaline to green/yellow in acidic conditions.
    • False negatives can arise from ascorbic acid, high specific gravity, or pathological conditions.
    • False positives may be due to high protein concentration or oxidizing agents present.

    Ketone Testing

    • Ketones, an intermediate metabolic product, include acetone and acetoacetic acid, detected by respective test strips.
    • Testing involves sodium nitroprusside reacting with acetone in alkaline conditions, resulting in a purple color change.
    • Time frame for this reaction is 40 seconds.

    Bilirubin Testing

    • Bilirubin is a degradation product of hemoglobin, measured using a diazo reaction.
    • False positives can occur with pigmented specimens or specific medications, such as levodopa.
    • Confirmatory tests (Ictotest) detect bilirubin in urine.
    • Only conjugated bilirubin (direct) will appear in urine.

    Blood Testing

    • The presence of blood is indicated through pseudo peroxidase activity of hemoglobin.
    • Reaction time is 60 seconds, detecting conditions such as hematuria and hemoglobinuria using a chromogen reaction.
    • False positives may arise due to nitrite concentration or specimen contamination.

    pH Testing

    • The pH is determined using a double indicator system (methyl red and bromthymol blue).
    • Normal urine pH ranges from 4.5 to 8.0; pH above 8.5 suggests specimen preservation issues.
    • False acidic readings can occur in alkaline urine scenarios.

    Protein Testing

    • The principle involves a protein error of the indicator, which can alter color without pH change.
    • Significant protein levels can cause false positives, especially in highly pigmented urine.
    • Proper timing and method of urine specimen preservation are crucial for accurate results.

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    Description

    This quiz focuses on the physical examination of urine, specifically on aspects like color and clarity. Test your knowledge on urochrome and the historical methods used for urine analysis. Perfect for students in healthcare or biology fields.

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