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newSchoolWorks.com › VoTechWorks › Health & Personal Services › Veterinary Technology / Vet Assistant › Advanced Veterinary Technology: Clinical Competencies for the AAS-Credentialed Technician › Lesson 4
HLT-VET42-09 · Lesson 4 · 20 clock hours · lab

Urinalysis and Fecal Diagnostics

Objective. The student will perform a complete urinalysis including gross evaluation, reagent strip, specific gravity measurement, and sediment microscopy, and a fecal flotation, accurately identifying common parasites and cellular elements.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

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Urinalysis and Fecal Diagnostics

Urinalysis (UA) and fecal flotation are two of the most commonly ordered in-house diagnostic tests in veterinary practice. As a credentialed veterinary technician, you are expected to perform both procedures independently, interpret findings, and communicate results accurately to the supervising veterinarian. A complete UA has three parts: gross evaluation, chemical (reagent strip) analysis, and microscopic sediment examination. Fecal flotation is the primary screening tool for intestinal parasites.

Safety and Handling Precautions

Urine and feces are biological hazards. Always wear gloves, a lab coat, and eye protection when handling samples. Some zoonotic parasites — including Toxocara spp. (roundworms) and Giardia — can infect humans; wash hands thoroughly after every procedure. Never pipette by mouth. Dispose of all materials, including used flotation solution, according to your facility's biohazard waste protocol. Formalin-based fixatives, if used, require a well-ventilated workspace.

Gross Evaluation of Urine

Record color, transparency (clarity), and any visible abnormalities before any chemical test.

Reagent Strip Analysis

Dip the strip fully into well-mixed urine for no more than one second, remove it, and tap the edge against the container rim to remove excess. Read each pad at the manufacturer's specified time interval — early or late reads give inaccurate results. Read the strip in good light, comparing pads to the color chart on the bottle.

Key parameters and their significance:

Important: Veterinary reagent strips are calibrated for veterinary species. Human urine dipsticks may give inaccurate results in animals, particularly for pH and SG.

Specific Gravity with the Refractometer

The refractometer measures the refractive index of urine, which correlates with solute concentration. Zero (calibrate) the instrument with distilled water before use — the line should read 1.000. Place one to two drops of well-mixed urine on the prism, close the cover, and read the veterinary SG scale while holding the scope toward a light source.

Normal reference ranges (approximate):

Isosthenuria (SG 1.008–1.012) indicates the kidney is neither concentrating nor diluting urine — a clinically significant finding. Hyposthenuria (SG < 1.008) indicates active dilution and is also clinically significant.

Urine Sediment Microscopy

Centrifuge urine in a conical tube at the speed and time recommended by your laboratory protocol (commonly 400–500 × g for 5 minutes). Pour off the supernatant, resuspend the pellet in the remaining drop, and transfer one drop to a clean slide with a coverslip. Scan under 10× (low power) to locate structures, then examine under 40× (high-dry) to identify them.

Common sediment findings:

Fecal Flotation

The most common method uses a flotation solution — zinc sulfate or sodium nitrate — with a specific gravity high enough to float parasite ova while leaving debris behind. Weigh or measure approximately 2–5 g of fresh feces. Mix thoroughly with flotation solution, strain through a tea strainer or gauze into a tube, and fill to a slight meniscus. Apply a coverslip and allow it to rest undisturbed for 10–20 minutes (time varies by solution and protocol). Carefully lift the coverslip straight up and place it solution-side down on a glass slide. Do not tilt the coverslip or ova will be lost.

Examine systematically under 10× using a back-and-forth (serpentine) pattern. Use 40× to confirm morphology. Use Foreyt's Veterinary Parasitology Reference Manual or a parasite identification chart to match egg size, shape, and internal structure.

Common ova and oocysts:

Recording and Reporting

Complete the UA worksheet in full. Record every parameter, even normal results. Flag any value outside the reference range with an asterisk or highlight for the veterinarian's review. Never discard samples until the veterinarian has reviewed results. Label all slides with patient ID, date, and technician initials if slides are to be retained.

Key terms10

IsosthenuriaA urine specific gravity of approximately 1.008–1.012, indicating the kidneys are neither concentrating nor diluting urine, which suggests impaired tubular function.
Specific gravity (SG)A measure of urine solute concentration relative to distilled water (1.000); measured in veterinary practice with a refractometer.
CastA cylindrical structure formed when protein or cells congeal in renal tubules and are then shed into urine; types include hyaline, granular, cellular, and waxy casts.
PyuriaThe presence of an abnormally elevated number of white blood cells in urine sediment, indicating urinary tract infection or inflammation.
Flotation solutionA solution with a specific gravity higher than that of parasite ova (e.g., zinc sulfate, sodium nitrate) used in fecal flotation to separate and concentrate ova at the surface.
HematuriaThe presence of red blood cells in the urine, detectable grossly (discolored urine) or microscopically in sediment.
GlucosuriaThe presence of glucose in urine, which is abnormal and may indicate diabetes mellitus or renal tubular dysfunction.
MorulaA cluster of cells seen inside a parasite egg (such as hookworm ova), representing early embryonic development; used as a morphologic identification feature.
RefractometerAn optical instrument used to measure the refractive index of a liquid; in urinalysis it provides an accurate reading of urine specific gravity.
Bipolar plugsPolar thickenings at each end of certain parasite eggs, most notably Trichuris vulpis (whipworm), giving the egg a barrel or football shape.

Worked examples4

1. You calibrate your refractometer with distilled water and the line reads 1.002 instead of 1.000. You then measure a urine sample and the refractometer reads 1.028. What is the corrected specific gravity?
  1. Step 1: Identify the calibration error. The instrument reads 1.002 on distilled water, which should read 1.000. The error (offset) is +0.002.
  2. Step 2: Subtract the offset from the sample reading to correct for instrument error. Corrected SG = 1.028 − 0.002 = 1.026.
  3. Step 3: If possible, re-zero the refractometer using the adjustment screw and re-measure. Always report the corrected value and note that the instrument was re-calibrated.
Answer: The corrected specific gravity is 1.026.
2. Your instructor's refractometer reads 1.034 on a canine urine sample. Your reading is 1.031. Is your result within the acceptable ±0.002 tolerance required for the lab practical?
  1. Step 1: Calculate the difference between your reading and the instructor's reference value. |1.031 − 1.034| = 0.003.
  2. Step 2: Compare the difference to the tolerance limit. The allowed tolerance is ±0.002, and 0.003 exceeds 0.002.
  3. Step 3: Conclude that your reading is outside the acceptable range. Recheck your technique: ensure the refractometer prism is clean, the instrument was zeroed with distilled water, the sample was well mixed, and you read the scale at eye level.
Answer: No. The difference of 0.003 exceeds the ±0.002 tolerance; the result does not pass. Recheck calibration and technique.
3. A cat's urine specific gravity is measured at 1.009. The owner reports the cat has been drinking and urinating excessively. What clinical term describes this SG finding, and what does it suggest?
  1. Step 1: Locate the SG value on the clinical interpretation scale. A value of 1.008–1.012 is defined as isosthenuric; a value below 1.008 is hyposthenuric.
  2. Step 2: The reading of 1.009 falls within the isosthenuric range (1.008–1.012).
  3. Step 3: Interpret in context. Combined with the history of polyuria and polydipsia (PU/PD), isosthenuria in a cat indicates the kidneys are unable to adequately concentrate urine — a significant finding that warrants further diagnostics such as blood chemistry, BUN, and creatinine to evaluate renal function.
Answer: The SG of 1.009 represents isosthenuria. In a cat with PU/PD, this finding is clinically significant and suggests impaired renal concentrating ability; further diagnostics are indicated.
4. During fecal flotation, you count 4 hookworm ova (Ancylostoma spp.) in one low-power (10×) field and 0 in the next 9 fields examined. How many total ova did you find, and what is the average ova per field across all 10 fields?
  1. Step 1: Sum the ova across all fields. 4 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 4 total ova.
  2. Step 2: Divide total ova by total fields examined to find the average. 4 ÷ 10 = 0.4 ova per field.
  3. Step 3: Record the finding as 'hookworm ova present' and note the approximate count. Even a small number of hookworm ova is a positive result and must be reported to the veterinarian, as hookworms are a significant pathogen and a zoonotic concern.
Answer: 4 total hookworm ova; average of 0.4 ova per 10× field. The test is positive for hookworm.

The math in this lesson1

Learners subtract a +0.002 refractometer offset to correct a 1.028 urine specific gravity to 1.026.
N-Q.3
Brush up in the math halls at newSchoolWorks.com:
In class: Collect a urine sample via free-catch method (simulated) and perform gross color and turbidity assessment, reagent strip analysis, and refractometer specific gravity measurement, recording all findings on the UA worksheet. · Prepare a centrifuged urine sediment slide, examine under 10× and 40× objective, and sketch and label any cells, casts, crystals, or organisms observed. · Prepare a fecal flotation using zinc sulfate or sodium nitrate solution, apply a coverslip, and examine the slide microscopically, identifying any parasitic ova or oocysts using a parasite identification reference.
Materials: Urine sample (simulated or donor animal), refractometer, urine reagent strips, centrifuge, microscope slides and coverslips, centrifuge tubes, fecal flotation solution, fecal loops, parasite identification chart, Foreyt's Veterinary Parasitology Reference Manual, UA worksheet
Check: Lab practical: student correctly identifies all reagent strip values, records specific gravity within ±0.002 of instructor measurement, and correctly identifies at least 3 of 4 planted sediment or fecal elements; pass = 85%.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Clinical Pathology / Laboratory Procedures
1. A refractometer reading of 1.008–1.012 in a dog's urine sample is best described as:
Parasitology
2. Which fecal parasite egg is best described as barrel-shaped with distinct bipolar plugs?
Parasitology / Laboratory Procedures
3. When performing a fecal flotation, what is the primary reason the specific gravity of the flotation solution must be higher than that of parasite ova?
Clinical Pathology / Urinalysis
4. A urine sediment slide prepared from a cystocentesis sample shows more than 5 white blood cells per high-power field. This finding is most consistent with:
Clinical Pathology / Laboratory Procedures
5. Before measuring urine specific gravity with a refractometer, you should first calibrate the instrument using:
Clinical Pathology / Scope of Practice
6. During urinalysis on a dog, the reagent strip shows a positive reaction for bilirubin. The technician should:
Clinical Pathology / Urinalysis
7. Which of the following urine sediment findings is MOST consistent with renal tubular injury rather than lower urinary tract disease?
Parasitology
8. A veterinary assistant finds ova that are oval, thin-walled, and contain a morula (cluster of cells) on a canine fecal flotation. These characteristics best describe:
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