Urinalysis (UA) – Macroscopic Evaluation, Urine Specific Gravity & Associated Pathologies

Vocabulary flashcards covering key terms, pathologies, and concepts related to macroscopic urinalysis evaluation, urine specific gravity measurement, and associated physiologic or pathologic findings as discussed in the lecture.

Urinalysis (UA)

Laboratory evaluation of urine to assess kidney function and detect systemic or urinary disease.

Pancreas (UA context)

Organ evaluated indirectly by measuring urine glucose levels.

Liver (UA context)

Organ assessed via urine bilirubin concentration.

Macroscopic Evaluation

First part of a routine UA; involves visual assessment of color, clarity, odor, and foam.

Straw-colored urine

Pale yellow urine indicating low concentration.

Amber urine

Dark yellow urine suggesting high concentration (dehydration).

Hematuria

Presence of red blood cells in urine; sample appears red–brown and cloudy.

Hemoglobinuria

Free hemoglobin in urine; red–brown but transparent sample often associated with hemolysis.

Myoglobinuria

Myoglobin in urine from muscle cell lysis; red–brown, transparent urine with normal plasma.

Bilirubinuria

Excess bilirubin in urine causing dark yellow to greenish discoloration that stains fingers.

Pseudomonas discoloration

Urinary tract infection with Pseudomonas spp. can turn urine blue-green.

Clear / Transparent (clarity)

Urine through which writing can be easily read.

Hazy urine

Slightly cloudy urine; lab sheet still visible but blurred.

Cloudy / Turbid urine

Noticeably opaque urine indicating suspended cells, crystals, or mucus.

Flocculent urine

Severely turbid urine containing visible floating particles or ‘floaters.’

Foamy urine

Excessive bubbles suggesting high protein content.

Urease-positive bacteria

Microbes that convert urea to ammonia, raising pH and producing strong ammonia odor.

Ammonia odor (urine)

Strong smell indicating cystitis from urease-positive bacteria.

Sweet/Fruity urine odor

Characteristic of ketonuria (diabetic ketoacidosis) or Pseudomonas infection.

Urine Specific Gravity (USG)

Ratio comparing urine density to distilled water; reflects renal tubular water reabsorption.

Refractometer

Instrument used to measure USG and total protein by light refraction.

Isosthenuria

USG 1.008–1.012 (up to 1.015 in cats); urine has same specific gravity as glomerular filtrate.

Fixed USG

Persistent isosthenuria despite hydration changes; indicates 2⁄3–3⁄4 nephron loss (renal failure).

Normal canine USG average

Approximately 1.025 (written 1.025, spoken ‘ten-twenty-five’).

Canine USG range

1.018–1.045 under normal conditions.

Pyometra effect

Uterine infection causing fever and diuresis, leading to low USG.

Diabetes Insipidus

ADH deficiency leading to dilute urine and decreased USG.

Cushing’s Disease

Endocrine disorder with polyuria/polydipsia; can lower USG.

Diuretics

Drugs that promote urine formation, decreasing USG.

Intravenous fluids

Fluid therapy that can dilute urine and lower USG.

Acute Renal Shutdown

Abrupt loss of kidney function causing oliguria and high USG.

Oliguria

Scanty urine production (<0.5 ml/kg/hr).

Diabetes Mellitus (urine)

Presence of glucose makes urine hypertonic; USG may be high despite pale color.

Hypertonic urine

Urine with high solute concentration that pulls water from tissues.

Exertional Rhabdomyolysis

Muscle breakdown in horses (‘Monday morning sickness’) leading to myoglobinuria.

Autoimmune Hemolytic Anemia (AIHA)

Immune-mediated RBC destruction causing hemoglobinuria.

Incompatible blood transfusion

Causes acute hemolysis and hemoglobinuria.

RBC parasites (e.g., Mycoplasma)

Can trigger hemolysis resulting in hemoglobinuria.

Snake venom (urine effect)

Toxins that lyse RBCs or muscle, causing hemoglobinuria or myoglobinuria.

Hepatobiliary Obstruction (HBO)

Blockage of bile flow leading to bilirubinuria and icterus.

Cholestasis

Stoppage of bile flow; one cause of icteric plasma and bilirubinuria.

Extravascular (EV) hemolysis

Normal RBC turnover; excessive EV hemolysis elevates bilirubin in blood and urine.

Urobilinogen

Water-soluble bilirubin metabolite formed in intestine; partly reabsorbed and excreted in urine.

Renal tubular function

Kidney’s ability to reabsorb water and concentrate urine; evaluated by USG.

Antidiuretic Hormone (ADH)

Hormone promoting water reabsorption; poor response lowers urine concentration.

Opaque container limitation

Plastic collection cups distort clarity assessment; transfer urine to glass to judge turbidity correctly.