Intro to UA

• HISTORY AND IMPORTANCE

  • References of the study of urine can be found in the drawings of cavemen and in Egyptian hieroglyphics, such as the Edwin smith surgical papyrus.
  • Urine is a fluid biopsy of the kidney and provides a "fountain" of information.
• Hippocrates


  Wrote the book of "uroscopy"
• Frederik Dekker


  Discovered albuminuria by boiling urine
• Thomas Bryant


  Published a book about "Pisse Prophets"
• Thomas Addis


  Addis count
• Richard Bright


  Introduced the concept of urinalysis as part of a doctor's routine patient examination
• Thudicum


  Urochrome - the pigment that causes yellow color of urine
• REASONS For Performing Urinalysis (CLSI)

  1. Diagnosis of disease
  2. Screening asymptomatic populations for undetected disorder
  3. Monitoring the progress of disease
  4. Monitoring the effectiveness of therapy
• URINE COMPOSITION

  • Urine consists of urea and other organic and inorganic chemicals dissolved in water.
  • Urine is normally 95% water and 5% solutes, although considerable variations in the concentrations of these solutes can occur owing to the influence of factors such as dietary intake, physical activity, body metabolism, and endocrine functions.
• Urea 


  Primary organic component. Product of protein and amino acid
• Creatinine 


  Product of creatine metabolism by muscles
• Uric acid 


  Product of nucleic acid breakdown in food and cells
• Chloride 


  Primary inorganic component. Found in combination with sodium and many other inorganic substances
• Sodium 


  Primarily from salt, varies by intake
• Potassium 


  Combined with chloride and other salts
• Phosphate 


  Combines with sodium to buffer the blood

  metabolism
• Ammonium 


  Regulates blood and tissue acidity
• Calcium 


  Combines with chloride, sulfate, and phosphate
• Nitrate 


  A normal urine constituent.
• Others Urine Composition


  Carbohydrates, pigments, fatty acids, mucin, enzymes, hormones; may be present in small amounts depending on diet and health
• • Urea is the major organic component of urine
  • Chloride is the major inorganic component of urine followed by Sodium then Potassium 
  • A high urea and creatinine content can identify fluid as urine.
  • The single most useful substance that identifies a fluid as urine is its uniquely high creatinine concentration (approximately 50 times that of plasma).
• URINE VOLUME

  • Urine volume depends on the amount of water that the kidneys excrete.
  • Factors that influence urine volume include - fluid intake, fuid loss from non-renal sources, variations in the secretion of ADM, and need to excrete increased amounts of dissolved solids, such as glucose or salts.
  • Normal daily urine output is usually 1200 to 1500 mL, a range of 600 to 2000 mL is considered normal
  • The kidney excretes two to three times more urine during the day than during the night
• Of the approximate 120 ml/min that was filtered at the glomerulus, only an average of I ml/min is finally excreted as urine. This quantity can range from 0.3 mL in dehydration to 15 mL in excessive hydration
• Oliguria 

  • Decrease in daily urine output 
  • Might progress to anuria
  • Less than 1mL/kg/hr in infants
  • Less than 0.5 mL/kg/hr in children
  • Less than 400mL/24hour (strasinger); or 500mL/24hr (henry)

  Causes:

  • Dehydration, water deprivation, vomiting, diarrhea, perspiration, severe burns, decrease renal blood flow, shock, hypotension, renal diseases (UTI, Renal tubular dysfunction, ESRD, Nephrotic syndrome, acute nephritis), and edema
• Polyuria

  • Increase in daily urine output
  • More than 2.5 to 3ml/kg/day in children
  • More than 2000ml per day (Other books: More than2.5L/24 hours)

  Causes:

  • Diabetes mellitus, diabetes insipidus, diuretics, caffeine, alcohol, nervousness, Excessive fluid intake, and lithium
• Nocturia

  • Increase or excessive excretion of urine at night
  • Normal day to night urine volume ratio = 2-3:1
  • More than 500mL urine
  • Urine specific gravity of less than 1.018

  Causes:

  • Common in elderly people
  • Common in pregnant women
  • Occurs with conditions characterized by reduced bladder capacity (e.g., pregnancy, bladder stones, prostate enlargement)
  • Excessive fluid intake at night
• Anuria

  • Cessation of urine flow, or no urine output
  • Sometimes defined as being < 100mL/24 hr during 2 to 3 consecutive days, in spite of a high fluid intake

  Causes:

  • Damage to the kidneys, Renal stones, renal tumors, Acute renal failure, Hemolytic transfusion reaction
• Analysis of urine in Differentiating between DM and DI

  Diabetes Mellitus

  • Due to defect in the pancreatic production of insulin
  • Increase Urine Specific gravity
  • Increase urine Glucose (glucosuria)

  Diabetes Insipidus

  • Due to decrease production or function of ADH
  • Decrease Urine Specific gravity
• SPECIMEN COLLECTION

  • Urine specimens should be delivered to the laboratory promptly and tested within a HouRs
  • Never discard a specimen before checking with a supervisor
• CHARACTERISTICS OF CONTAINER

  • Clean, Dry, Leak-proof
  • With Screw top lids - they are less likely to leak than snap-on lids
  • Wide mouth, and wide flat bottom
  • Made of sterile material
  • The recommended container capacity is 50mL
  • The required specimen volume for urine microscopic analysis is 10 to 15 ml; average of 12 ml
  • Containers should stand upright, have an opening of at least 4 to 5 cm, and have a capacity of 50 to 100 ml
• LABELS

  • Patient's name
  • Patient identification number
  • Date and time of collection
  • Additional information such as age, sex, etc.

  Labels must be attached to the BODY OF CONTAINER, not to the lid and should not become detached if the container is refrigerated/frozen.
• REQUISITION FORM

  • A requisition form must accompany specimens delivered to the laboratory
• POLICY FOR HANDLING MISLABELED SPECIMENS

  • Do NOT assume any information about the specimen or patient.
  • Do NOT relabel an incorrectly labeled specimen.
  • Do NOT discard the specimen until investigation is complete.
  • Leave specimen EXACTLY as you receive it; put in the refrigerator for preservation until errors can be resolved.
• POLICY FOR HANDLING MISLABELED SPECIMENS

  • Notify floor, nursing station, doctor's office, etc. of problem and why it must be corrected for analysis to continue.
  • Identify problem on specimen requisition with date, time, and your initials
  • Make person responsible for specimen collection participate in solution of problem(s). Any action taken should be documented on the requisition slip.
  • Report all mislabeled specimens to the appropriate supervisor.
• WHEN TO REJECT SPECIMEN? 

  1. Specimen in unlabeled containers
  2. Non matching labels and requisition forms
  3. Specimens contaminated with feces or toilet papers
  4. Containers with contaminated exteriors
  5. Specimens of insufficient quantity
  6. Specimens that have improperly transported

  • Never discard a specimen before checking with a supervisors
• CHANGES IN UNPRESERVED URINE (Strasinger): Modified / Darkened

  Color - Oxidation or reduction of metabolites
• CHANGES IN UNPRESERVED URINE (Strasinger): Increased PBaON-C

  • Ph - Breakdown of urea to ammonia by urease-producing bacteria / loss of CO2
  • Bacteria - Multiplication
  • Odor - Bacterial multiplication or breakdown of urea to ammonia
  • Nitrite - Multiplication of nitrate reducing bacteria
• CHANGES IN UNPRESERVED URINE (Strasinger): Decreased

  • Clarity - Bacterial growth, and precipitation of amorphous material
  • Glucose - Glycolysis and bacterial use
  • Ketones - Volatilization and bacterial metabolism
  • Bilirubin - Photo oxidation to biliverdin/ light exposure
  • Urobilinogen - Oxidation to urobilin
  • RBC, WBC, and casts - Disintegration in dilute alkaline urine
  • Trichomonads - Loss of characteristic, motility and death
• Protein / Albumin is least or not affected in unpreserved urine 
• Urine Preservative: Refrigeration (2-8'C) - The easiest and most common

  • Advantage: Does not interfere with chemical tests
  • Disadvantage:
  • PRECIPITATES AMORPHOUS CRYSTALS
  • Raises specific gravity by hydrometer
  • Additional Information: Prevents bacterial growth for 24 hours.