Chemical Examination

• What is the primary focus of urine analysis?

  To examine different substances or analytes present in the urine sample
• What is the traditional method of biochemical testing for urine analysis?

  It requires larger volumes of samples and is very tedious
• How do reagent strip pads work in urine analysis?

  They are impregnated with chemicals that react with the urine specimen
• What are the four main types of examination in urine analysis?

  Specimen Evaluation, Physical Examination, Chemical Examination, Sediment Examination
• What is the purpose of using chemical-impregnated absorbent pads in urine analysis?

  To provide a simple, rapid means for performing medically significant chemical analysis of urine
• How is the color produced on the reagent strip interpreted?

  By comparing it with a chart supplied by the manufacturer
• What does a semiquantitative value of trace, 1+, 2+, 3+, or 4+ indicate in urine analysis?

  It indicates the intensity of the color produced for each substance being tested
• What are the two types of reagent strips mentioned?

  Multistix and Chemstrips
• What are the steps in the reagent strip technique for urine analysis?

  1. Dip the reagent strip into a well-mixed urine specimen.
  2. Remove excess urine by touching the edge of the strip to the container.
  3. Blot the edge of the strip on a disposable reagent pad.
  4. Wait for the specified length of time for reactions.
  5. Compare the colored reactions against the manufacturer’s chart.
• What are the care instructions for reagent strips?

  • Store with desiccant in an opaque, tightly closed container.
  • Store below 30°C/Room temperature; do not freeze.
  • Do not expose to volatile fumes.
  • Do not use past the expiration date.
  • Do not use if chemical pads become discolored.
  • Remove strip immediately prior to use.
  • Do not touch the chemical pads.
• How often must reagent strips be checked for quality control?

  At least once every 24 hours
• What is not recommended as a negative control for reagent strips?

  Distilled water
• What are the parameters tested by reagent strips?

  • 4-parameter: glucose, protein, specific gravity, and pH
  • 10-parameter: 4-parameter plus bilirubin, ketones, blood, urobilinogen, nitrite, and leukocyte esterase
  • 11-parameter: 10-parameter plus ascorbic acid
• What is the principle of the glucose test on reagent strips?

  Double Sequential Enzyme Reaction
• What is the renal threshold for glucose?

  160-180 mg/dL
• What does the presence of glucose in urine indicate?

  It may indicate a metabolic problem or diabetes mellitus
• What are the causes of hyperglycemia associated with increased urine glucose?

  • Diabetes Mellitus (insulin deficiency)
  • Cushing’s Syndrome (increased cortisol)
  • Pheochromocytoma (increased catecholamines)
  • Acromegaly (increased growth hormone)
  • Hyperthyroidism (increased T3 or T4)
• What is the principle of the reagent strip for protein?

  Double Indicator System
• What color indicates the presence of protein in the urine using the reagent strip?

  Blue-green color
• What does a positive result in the Sulfosalicylic Acid Precipitation Test indicate?

  It indicates turbidity or cloudiness due to protein presence
• What is the most frequently tested substance in urine?

  Glucose (Dextrose)
• What is the significance of renal threshold in glucose testing?

  It is the plasma concentration at which tubular reabsorption of glucose stops
• What are the clinical implications of glucose in urine?

  It can indicate conditions like diabetes mellitus or impaired tubular reabsorption
• What are the causes of impaired tubular reabsorption of glucose?

  • Fanconi syndrome (defective tubular reabsorption)
• What is the principle of the Clinitest/Benedict’s Test?

  It is a nonspecific test for reducing sugars
• What types of sugars can be detected by the Clinitest/Benedict’s Test?

  Galactose, Lactose, Fructose, Maltose, Pentoses, Ascorbic Acid, Certain Drug Metabolites, and Antibiotics
• What are the clinical significances of urine pH?

  • Identifying respiratory or metabolic acidosis or alkalosis
  • Detecting defects in renal tubular secretion and reabsorption
  • Assessing renal calculi formation
  • Monitoring treatment of urinary tract infections
  • Identifying precipitation/identification of crystals
  • Determining unsatisfactory specimens
• What is the normal pH range for a random urine specimen?

  pH 4.5 to 8.0
• What is the normal pH range for first morning urine?

  pH 5.0 to 6.0
• What can cause urine to become alkaline?

  Renal Tubular Acidosis, vegetarian diet, and old specimens
• What is the effect of a high protein diet on urine pH?

  It causes urine to become more acidic
• What is the significance of acidic urine in relation to diabetes mellitus?

  It is caused by increased ketones due to lipolysis
• What is the relationship between dehydration and urine pH?

  Dehydration can lead to increased ketones, resulting in acidic urine
• How does renal tubular acidosis affect urine pH?

  It results in alkaline urine due to the inability to excrete hydrogen ions
• What is the effect of hyperventilation on urine pH?

  It results in alkaline urine due to decreased carbonic acid
• What is the principle of the reagent strip for pH testing?

  Double Indicator System using methyl red and bromthymol blue
• What can cause interference in pH testing of old specimens?

  Old specimens can lead to alkaline urine
• What is the significance of urine pH in identifying crystals?

  It helps in identifying the type of crystals present based on urine acidity
• What is the relationship between urine pH and unsatisfactory specimens?

  Unsatisfactory specimens may have altered pH due to age or contamination
• What is the significance of protein in urine analysis?

  It is the most indicative of renal disease