intro to urinalysis

• Wrote a book on “uroscopy”

  5th century BCE
• Instruction in urine examination as part of their training

  Middle Ages
• Development of 20 different color charts

  1140 CE
• Frederik Dekkers’s discovered albuminuria by boiling of urine


  1694
• This is a progress from “ant testing” and ”taste testing” for glucose
• Charlatans (pisse prophets) began offering predictions to the public


  1627
• This gave way to the passing of the first medical licensure law in England
• The invention of microscope led to the examination and quantitation of urinary sediment by Thomas Addis


  17th century
• Richard Bright introduced the concept of urinalysis as part of routine patient examination

  1827
• The number and complexity of the tests performed in a urinalysis had reached a point of impracticality

  1930s
• Urinalysis began to disappear from routine examinations
• The kidneys continuously form urine as an ultrafiltrate of plasma
• Reabsorption of water and filtered substances essential to body function converts approximately 170,000 mL of filtered plasma
• Average daily urine output is 1200 mL
• Urine is normally 95% water and 5% solutes
• Factors affecting urine composition

  • Dietary intake
  • Physical activity
  • Body metabolism
  • Endocrine functions
• Organic substances in urine

  • Urea
  • Creatinine
  • Uric acid
• Inorganic substances in urine

  • Chloride
  • Sodium
  • Potassium
• Other substances in urine

  • Hormones
  • Vitamins
  • Medications
• May also contain

  • Cells
  • Casts
  • Crystals
  • Mucus
  • Bacteria
• Urine volume depends on the amount of water that the kidneys excrete
• Water is a major body constituent; therefore, the amount excreted is usually determined by the body’s state of hydration
• Factors that influence urine volume

  • Fluid intake
  • Fluid loss from nonrenal sources
  • Variations in the secretion of antidiuretic hormone (ADH)
  • Need to excrete increased amounts of dissolved solids
• Average daily output is 1200 to 1500 mL/day (600 to 2000 mL/day is considered normal)
• Oliguria


  Abnormal decrease in urine output
• Oliguria in different age groups

  • Infants: <1 mL/kg/hr
  • Children: <0.5 mL/kg/hr
  • Adults: <400 mL/day
• Clinical significance of oliguria includes dehydration due to vomiting, diarrhea, perspiration or severe burns
• Anuria


  Total suppression of urine production / cessation of urine flow
• Clinical significance of anuria includes serious damage to kidneys and decreased blood flow to the kidneys
• Nocturia

  Excretion of more than 500 mL of urine at night
• Clinical significance of nocturia includes prostatic cancer
• Polyuria


  Abnormal increase in daily urine output
• Polyuria in different age groups

  • Children: 2.5 to 3 mL/kg/day
  • Adults: >2.5 L/day
• Clinical significance of polyuria includes Diabetes Mellitus or Diabetes Insipidus
• Differentiation between DM and DI is important
• Specimen collection containers

  • Dry
  • Clean
  • Leak proof
  • Screw top lids
  • Wide mouth
  • Made from clear material with 50 mL capacity
• Specimen labels

  • Patient name
  • Identification number
  • Date
  • Time of collection
• Requisition form must accompany specimens delivered to the laboratory
• Reject specimens that are

  • Unlabeled or improperly labeled
  • Non matching labels with requisition form
  • Contaminated with feces or toilet paper
  • Of insufficient quantity
  • Transported improperly
  • Not preserved correctly during a time delay
  • For urine culture collected in a nonsterile container
  • Inappropriate for the type of testing needed
• After collection, specimens should be delivered to the laboratory promptly and tested within 2 hours