Chapter_027 (1)

Unit 5: Urinalysis

Chapter 27: Physical Examination of Urine

Routine Analysis

Physical Properties

• Attributes assessed include:

  • Volume

  • Color

  • Odor

  • Transparency

  • Specific Gravity

Urine Volume Considerations

• Distinguish between:

  • Pollakiuria: Frequent urination

  • Polyuria: Increased urine production

• Influencing factors:

  • Fluid intake

  • External losses

  • Environmental conditions

  • Activity levels

Urine Production Terms

Polyuria

• Increased water intake (polydipsia) often accompanies it.

• Characteristics:

  • Pale/light yellow urine

  • Low specific gravity (SG)

• Associated with:

  • Nephritis

  • Diabetes mellitus

  • Pyometra

  • Liver disease

  • Certain medications (diuretics, corticosteroids)

Oliguria

• Decreased urine output with high SG.

• Causes include:

  • Restricted water access

  • Environmental heat

  • Shock

  • Dehydration

Anuria

• Absence of urine indicates:

  • Urethral obstruction

  • Urinary bladder rupture

  • Renal shutdown

Urine Color Assessment

• Normal range: Light yellow to amber (urochromes).

• Darker urine indicates higher concentration and SG.

• Abnormal colors:

  • Yellow-brown/green: Bile pigments

  • Red/brown: RBCs (hematuria) or hemoglobin (hemoglobinuria).

Clarity or Transparency

• Most species: Clear or transparent.

• Exceptions:

  • Equine: Normally cloudy

  • Rabbits: Milky due to calcium carbonate crystals.

• Recorded as:

  • Clear, slightly cloudy, cloudy, or turbid.

Odor Evaluations

• Less diagnostic, but species-specific:

  • Ammonia indicates cystitis.

  • Sweet or fruity odor suggests ketones (diabetes, ketosis in cows).

Specific Gravity (SG) Measuring

Definition

• Comparison of weight/density of urine to distilled water.

• SG is influenced by dissolved solutes.

Equipment

• Preferred: Refractometer.

• Less common: Urinometer (requires larger samples).

• Least reliable: Reagent strips.

Refractometer Function

• Measures light wave bending in urine.

• Must be calibrated for accuracy.

Altered Urine SG Causes

Increases in SG

• Reduced water intake, fluid loss, solute excretion (acute renal failure, dehydration).

Decreases in SG

• Reduced kidney absorption (pyometra, diabetes insipidus, liver disease).

Isosthenuria

• SG close to glomerular filtrate (1.008 - 1.012).

• Indicates poor kidney function; chronic renal disease.

Summary

• Review of physical properties:

  • Normal urine output and characteristic indicators.