Laboratory Procedures Free guide

Hematology I: PCV, Total Protein, Blood Smears and the CBC

Laboratory Procedures (D4 C; K25, K27) 14 min read, 3,258 words Last verified

The bench hematology a veterinary technician does every day: microhematocrit PCV, plasma color, refractometer total protein, wedge smears, staining, the 100-cell differential, absolute counts and platelet estimates.

Introduction

The complete blood count (CBC) is one of the tests a veterinary technician runs most often. A CBC, also called a hemogram, reports red blood cells (RBCs), white blood cells (WBCs) and platelets. It also covers the look of the plasma and a total protein estimate.9 Much of it happens at the bench: spinning a PCV tube, reading a refractometer, making and staining a smear, counting 100 white cells and estimating platelets.

The analyzer does not replace these skills. Automated differentials perform poorly on nonhuman blood, and Merck advises examining a blood film for every patient sample.1

Key facts

  • EDTA (purple or lavender top) is the anticoagulant for hematology. Fill the tube to the mark and mix it right away.110
  • Packed cell volume (PCV) by microhematocrit is the reference method. Fill the tube about three quarters full, seal one end and spin it.1
  • A spun tube shows packed red cells at the bottom, then the buffy coat (white cells, with platelets on top), then plasma.312
  • A refractometer reading of plasma measures total solids, an estimate of total protein. Lipemia falsely raises it; bilirubin does not change it.4
  • Hold the spreader slide at about 30 to 40 degrees. A good smear runs out of blood before the end of the slide and forms a feathered edge.10
  • Do the differential and the platelet estimate in the monolayer. Check the feathered edge first for platelet clumps.5
  • Absolute count = total WBC count × the cell type's percentage. Percentages alone can mislead.1
  • Platelet estimate: average platelets per 100× oil field × 15,000 = platelets/µL (a rough guide).6

How the VTNE tests this

  • Perform the test: Domain 4 Task C lists hematology among the tests a technician performs, and Task D covers maintaining laboratory equipment. K25 covers laboratory principles and methods; K27 covers normal and abnormal results.16
  • Identify: spun tube layers, smear zones, or where to do a differential.
  • Troubleshoot: a smear with no feathered edge, a falsely low platelet count, or an underfilled tube.
  • Calculate: an absolute count from a percentage, a platelet estimate, a corrected WBC count, or a unit conversion (K7 applied mathematics).16
  • Interpret plasma: what red, yellow or milky plasma suggests, and where yellow is normal.

Core concepts

What a CBC contains

The erythrogram covers the red cells: PCV or hematocrit, hemoglobin, RBC count and the RBC indices. The leukogram is the total WBC count and the differential. The thrombogram is the platelet count and size.9 Merck notes that PCV, hemoglobin and RBC count are three ways to measure the same thing. They give the mean corpuscular volume (MCV, average cell size) and the mean corpuscular hemoglobin concentration (MCHC).1

PCV and hematocrit are not the same measurement

PCV is measured directly: the height of the red cell column in a spun microhematocrit tube. Hematocrit (HCT) is calculated by the analyzer from the MCV and RBC count: HCT = (MCV × RBC count) ÷ 10. An error in the MCV or RBC count carries into the HCT, but not always into the PCV.3 Both are reported as a percentage. To convert to SI units, divide by 100 to get L/L.3

PCV changes with body water. Dehydration can raise a PCV above the reference interval, or hide an anemia by bringing a low PCV back into range.3 This is why PCV is read together with total protein. Blood loss usually lowers both the red cell values and the total solids.9

What the spun tube shows besides the PCV

After the spin, note the PCV and the buffy coat, which holds the white cells and platelets; its thickness is only a very rough guide to the WBC count.1 Note the plasma color too; it is normally clear and colorless in dogs and cats.12 You can also score and break the tube to read the plasma on a refractometer, or to make a buffy coat smear that concentrates nucleated cells.3

Layers in a spun microhematocrit tube and how to read the PCV Clay plug (sealed end) Not part of the reading Packed red cells Top of this column = PCV Bottom of the red cells = 0% Buffy coat White cells, with a thin layer of platelets on top Plasma Top of plasma = 100% Note color: clear, red,yellow or milky Empty part of tube 0% PCV 100% Read the PCV at the top of the red cells,not at the top of the buffy coat.
Figure 1. A spun microhematocrit tube. Line up the bottom of the red cell column with 0% and the top of the plasma with 100%, then read the PCV where the red cells end. The buffy coat holds white cells with a thin layer of platelets on top. Note the plasma color before you break the tube for a total protein reading.
Table 1. Plasma appearance in the spun tube
Plasma looksTermWhat it means for the technician
Clear, colorlessNormal (dog, cat)Record as normal.
Pink to redHemolysisFree hemoglobin from ruptured red cells, either a collection or storage artifact or true hemolysis in the patient. In vitro hemolysis lowers the PCV and HCT.315
YellowIcterusRaised bilirubin in most species. Horse and cattle plasma is normally yellow.13
Hazy to milky whiteLipemiaChylomicrons or triglycerides. Falsely raises the refractometer reading and the hemoglobin reading.1413

Sources: Merck, Clinical Hematology and Clinical Biochemistry113; eClinPath, Hematocrit, Total Protein and Interference Indices3415; Claude and Walton.12

Total protein by refractometer

A refractometer measures the refractive index of the sample against water. The reading is total solids, so it is only an estimate of protein: sodium, glucose, urea, cholesterol and colloids such as hetastarch also bend light. Lipemia falsely increases the result. Moderate to severe hemolysis blurs the line. Bilirubin does not interfere.4 Plasma total protein includes fibrinogen, so a refractometer result is usually higher than a serum chemistry total protein, especially in dogs and cats.4 Results are in g/dL; multiply by 10 for g/L.13

How analyzers count cells

Analyzers use one of two main methods. Impedance counters (the Coulter principle) count and size cells by the pulse each cell makes as it passes through an electrical field. Laser-based analyzers use flow cytometry and measure the light each cell scatters.86 Centrifugal buffy coat instruments give only approximate counts and cannot separate lymphocytes from monocytes.1 Every counting method counts nuclei. Nucleated red blood cells (nRBCs) are therefore counted as white cells until the count is corrected.7

Relative and absolute counts

The differential gives the percentage of each white cell type. Interpretation needs the absolute number, which is the total WBC count multiplied by that fraction. An increased percentage caused by an absolute decrease in another cell type is not an increase at all.1 Reference laboratories usually report absolute counts; in house, you calculate them yourself.5

Table 2. Same percentages, different meaning: two dogs with identical differentials
Cell type (%)Dog A, WBC 4.0 × 10³/µLDog B, WBC 14.0 × 10³/µLMerck dog range (× 10³/µL)
Segmented neutrophils, 65%2.6 (low)9.12.9 to 12.0
Lymphocytes, 30%1.24.2 (high)0.4 to 2.9
Monocytes, 4%0.160.560.1 to 1.4
Eosinophils, 1%0.040.140 to 1.3

Worked example (invented patients). Ranges: Merck.2 Both dogs have 30% lymphocytes, above the Merck range of 8 to 21%. Dog A really has too few neutrophils; its lymphocyte number is normal. Dog B has a true lymphocytosis.

Procedure or technique

1. Collect and handle the sample

  1. Collect into EDTA. Heparin makes cells clump, and liquid citrate dilutes the sample.10 Citrate dilutes PCV by its volume, which is 10% of the collection volume.3
  2. Fill the tube to the mark. EDTA is hypertonic, so an underfilled tube shrinks red cells, lowers the MCV, raises the MCHC and can cause echinocytes (spiky red cells).101
  3. Mix at once by gentle inversion or rolling. Do not shake.10 Before testing, invert the tube 8 to 10 times so settled cells are evenly spread.11
  4. If the sample cannot be run right away, make 2 to 3 smears now and send them unfixed and unstained with the tube. After a few hours platelets clump, neutrophils can look like bands and red cells swell.10
  5. Refrigerate the EDTA tube, but never the smears. Keep slides away from formalin fumes, which alter staining.10

2. PCV by microhematocrit

  1. Fill a capillary tube about three quarters full with well-mixed blood.1
  2. Seal one end with clay, or heat-seal it if a burner is available.1
  3. Load the microhematocrit centrifuge with the tubes balanced, close the lid and spin.18 Times vary: Merck describes 6 minutes, and Cornell spins ruminant tubes for 10 minutes and other species for 3, because ruminant red cells may not pack as well.13 A 2025 study found 3 minutes enough for dogs and donkeys, 5 for cattle and 10 for sheep.17
  4. Read the PCV on a microhematocrit reader. Hold the tube upright, put the top of the clay (the bottom of the red cells) on the 0% line and the plasma meniscus on the 100% line, then read at the top of the red cell column. Leave the buffy coat out of the reading.171
  5. Record the plasma color and the buffy coat size.1

3. Total protein by refractometer

  1. Calibrate the refractometer daily with distilled water. On an analog model, water should read on the 1.000 specific gravity line; turn the calibration screw if it does not.14
  2. Score and snap the tube just above the buffy coat and place the plasma on the prism.3
  3. Close the cover, hold the refractometer toward a light and read the protein scale in g/dL, not the urine specific gravity scale.1314
  4. Clean the prism after each use and wipe it dry with a soft cloth or optical tissue.14

4. Make a wedge smear

  1. Use clean slides with clean edges. Do not touch the spreading edge.10
  2. Place a drop of well-mixed blood about 4 mm across, about 0.5 cm from the frosted end.10
  3. Hold the spreader slide at about 30 to 40 degrees in front of the drop. Draw it back into the drop and let the blood spread along its edge.1011
  4. Push forward in one quick, smooth motion. Keep the angle and light, even contact. Do not lift the spreader until the smear is complete.1011
  5. Dry the smear quickly by fanning it in the air, then label it.111

A correct smear starts thick near the drop and thins to a feathered edge. Cornell says it should reach no more than three quarters of the way along the slide.10 Raise the angle for anemic blood, which is thin, and lower it for thick blood.12

Wedge blood smear: how it is made and the zones of a finished smear A. Side view: making the smear 30 to 40° Spreader slide Back into the drop and pause, then push forward in one quick, smooth motion. Keep the angle the same. Drop about 4 mm wide, placed about 0.5 cm from the frosted end B. Top view: zones of a finished smear Frosted label end Label Body and base Too thick for detail; scan at low power Monolayer Count and judge cells here Feathered edge Check for clumps and microfilariae
Figure 2. Making a wedge smear (A) and the zones of the finished smear (B). Scan the feathered edge at low power for platelet clumps and microfilariae, then do the differential, platelet estimate and morphology in the monolayer just behind it. The body and base are too thick for detail.

5. Stain the smear

Romanowsky-type stains, such as Wright-Giemsa and the quick stains (for example Diff-Quik), are used for blood. A quick stain is three dips: a fixative (usually methanol), then eosin, then methylene blue.11 Bellwood fixes for at least 60 seconds and gives 30 seconds in each dye, adjusting for stain age and smear thickness, then rinses with distilled water.11 Air dry or use a hair dryer; do not wipe it dry.1 Keep a "clean" stain set for blood and a separate "dirty" set for ear, urine and purulent samples.11 New methylene blue, used for reticulocytes, is covered in Hematology II.1

6. Read the smear in order

  1. Low power (10× objective). Check the feathered edge for platelet clumps, large abnormal cells and microfilariae, then scan the body and base. White cells should be spread evenly, not piled at the edge.5
  2. Find the monolayer. It is usually about one 10× field behind the feathered edge. Red cells are separate or barely touching.5
  3. Differential under oil (50× or 100× objective). Move across the monolayer in a pattern that does not cover the same area twice. Classify each white cell until you reach 100. The 40× objective is not recommended for this.5
  4. Count nRBCs separately per 100 white cells. Do not include them in the 100.5
  5. Estimate platelets in the monolayer. Average 5 to 10 oil fields. Each platelet per field is about 15,000/µL.5
  6. Describe morphology of red cells, white cells and platelets, and look for infectious agents.5
Table 3. Smear faults and their fixes
FaultFix (one or more)
Too long, runs off the end, no feathered edgeSmaller drop; steeper angle; faster push
Too short or smallLarger drop; lower angle; slower push
Too thickSmaller drop; lower angle; faster push
Too thinLarger drop; steeper angle; slower push
Waves and ridgesRelax the wrist (too much downward force makes the spreader skip); faster push; even contact
Part of the drop left behindDraw the spreader fully back through the drop; keep its whole edge in contact

Source: Cornell University Animal Health Diagnostic Center, Samples for Hematology.10

Flowchart

Check every smear before you stain it. A poor smear cannot give a good differential.

Decision tree: troubleshooting a wedge blood smear before staining Hold the air-dried, unstained smearup to the light and look at its shapeSmear runs to the endof the slide with nofeathered edge?Smaller drop,steeper angle,faster push.Smear too shortor too small?Larger drop,lower angle,slower push.Waves or ridgesacross the smear?Relax the wrist,light even contact,smooth faster push.Part of the dropleft behind atthe start?Draw the spreaderfully back throughthe drop first.Smear is usable. Label it,stain it, then scan thefeathered edge at low powerbefore counting in the monolayer.After any fix,make a new smearfrom well-mixedblood and recheck.YesNoYesNoYesNoYesNo Clean slides with clean edges prevent many faults.
Figure 3. Smear troubleshooting before staining. Each "yes" branch gives the change to make, from the Cornell table of smear faults. After any change, make a new smear from well-mixed blood and check it again. Only a smear that passes every check goes on to staining and counting.

Reference intervals

Reference intervals vary with the laboratory, analyzer and animal population. Always use the interval from the laboratory or analyzer that ran the sample.92 The Merck values below are for study only.

Table 4. Selected CBC reference ranges (Merck Veterinary Manual)
Test (units)DogCatHorseCow
PCV (%)35 to 5730 to 4527 to 4324 to 46
WBC (× 10³/µL)5.0 to 14.15.5 to 19.55.6 to 12.14.0 to 12.0
Segmented neutrophils (× 10³/µL)2.9 to 12.02.5 to 12.52.9 to 8.50.6 to 4.0
Lymphocytes (× 10³/µL)0.4 to 2.91.5 to 7.01.2 to 5.12.5 to 7.5
Monocytes (× 10³/µL)0.1 to 1.40 to 0.90 to 0.70 to 0.9
Eosinophils (× 10³/µL)0 to 1.30 to 0.80 to 0.80 to 2.4
Basophils (× 10³/µL)0 to 0.140 to 0.20 to 0.30 to 0.2
Platelets (× 10³/µL)211 to 621300 to 800117 to 256100 to 800
Plasma protein (g/dL)6.0 to 7.56.0 to 7.56.0 to 8.56.0 to 8.0

Source: Fielder SE, Merck Veterinary Manual, Hematology (Complete Blood Count) Reference Ranges.2 Other sources differ: Claude and Walton give a PCV of 37 to 55% for adult dogs and total protein of 5.9 to 7.8 g/dL.12

Species differences

  • Dog. Some breeds run higher red cell values. eClinPath cites an average HCT of 59% in adult Greyhounds, and higher values in Dachshunds and Whippets.3 Some large breeds, such as German Shepherds and Rottweilers, normally have relatively high eosinophil counts.1
  • Cat. Feline platelets clump at the slightest handling, so accurate counts are hard to get. Use a large vein (cephalic or jugular) and a 22 or 23 G needle, mix with the anticoagulant at once and count promptly.6 Cats normally have larger platelets than other domestic animals, and some are as large as red cells.51 Lymphocytosis can be physiologic, especially in cats.1
  • Horse. Platelets are faint on the smear, and normal counts are about half those of other species. eClinPath treats an average of 6 per oil field as within the low end of the horse range.51 Rouleaux (red cells stacked like coins) is normal in horses but abnormal in other species.5 Splenic contraction caused by epinephrine can raise the PCV.3 Equine plasma is normally yellow, and equine white cells deteriorate fast, so make a smear at once.131
  • Ruminants. Bovine plasma is normally yellow.13 Cornell spins ruminant microhematocrit tubes longer (10 minutes).3 Basophils are easier to find in cattle than in most species.1
  • Birds and reptiles. Platelets (thrombocytes) are true cells with nuclei, and the neutrophil is called a heterophil.1 EDTA is still preferred, but some birds (for example cranes) and reptiles (for example turtles) hemolyze in it. For them, collect into citrate at 1 part citrate to 9 parts blood.10

Calculation

1. Absolute count. A dog's WBC count is 12.0 × 10³/µL. The 100-cell differential has 75 segmented neutrophils.

12.0 × 10³/µL × 0.75 = 9.0 × 10³/µL (9,000/µL) neutrophils.15

2. Correcting the WBC count for nRBCs. The analyzer reports 22.0 × 10³ nucleated cells/µL, and you counted 10 nRBCs per 100 WBCs. Corrected WBC = nucleated cell count × [100 ÷ (nRBC + 100)].7

22.0 × 10³/µL × (100 ÷ 110) = 20.0 × 10³/µL. eClinPath corrects when more than 5 nRBCs per 100 WBCs are counted.5

3. Platelet estimate. You count 14, 16, 15, 13 and 17 platelets in five oil fields of the monolayer and see no clumps.

(14 + 16 + 15 + 13 + 17) ÷ 5 fields = 15 platelets/field. 15 × 15,000/µL = 225,000/µL, within the Merck dog range of 211,000 to 621,000/µL.562

4. Units. PCV 42% ÷ 100 = 0.42 L/L.3 Total protein 6.5 g/dL × 10 = 65 g/L.13

Safety, legal and client education

  • Wear disposable gloves when handling blood and other samples.14 OSHA counts broken capillary tubes as sharps; discard them at once in a closable, puncture-resistant sharps container.19
  • Balance the centrifuge, keep the lid closed while it runs and never open it until the rotor has stopped.18
  • Label every tube with at least the patient and owner names, and every slide before staining.1011
  • In-house analyzers need strict quality assurance. Merck advises running control samples of known composition at least daily, in normal and abnormal ranges, and testing no patient samples unless the controls are within limits.131
  • Clients: explain that a single CBC is a snapshot. The marrow and blood respond within minutes to hours, which is why critical patients may be rechecked every 24 hours.9 The veterinarian interprets; the technician reports values, flags and smear findings.

Common mistakes and exam traps

  • Reading the PCV at the top of the buffy coat. Read at the top of the red cells.3
  • Counting at the feathered edge. Cells there are flattened or broken, and red cells can mimic spherocytes. Count in the monolayer.5
  • Calling a platelet count low without checking for clumps. Clumps lower the count by any method, so treat the result as a minimum. Scan the feathered edge first, especially in cats.6
  • Interpreting percentages. Convert to absolute counts first.1
  • Using heparin or a half-full EDTA tube for a CBC. Heparin clumps cells; underfilling shrinks red cells.10
  • Calling yellow horse plasma icteric. Equine and bovine plasma is normally yellow.13

Quick review

  1. EDTA, filled to the mark and mixed at once, is the hematology tube.
  2. PCV is measured; HCT is calculated as (MCV × RBC) ÷ 10.
  3. Spun tube from bottom to top: clay, red cells, buffy coat, plasma.
  4. Normal dog and cat plasma is clear; red is hemolysis, yellow is icterus, milky is lipemia.
  5. Horse and cattle plasma is normally yellow.
  6. Refractometer total protein is total solids; lipemia raises it, bilirubin does not.
  7. Spreader at 30 to 40 degrees; a good smear ends in a feathered edge.
  8. Scan the feathered edge for clumps and microfilariae; count in the monolayer.
  9. Count 100 white cells and record nRBCs separately per 100 WBCs.
  10. Absolute count = total WBC × percentage as a decimal.
  11. Platelet estimate: average per oil field × 15,000/µL.
  12. Use the reference interval from the laboratory that ran the sample.

Test yourself

5 questions written for this guide. Pick an answer, then check it.

Question 1A dog has a total WBC count of 8.0 × 10³/µL. On the 100-cell differential you count 70 segmented neutrophils, 20 lymphocytes, 8 monocytes and 2 eosinophils. What is the absolute lymphocyte count?

Show answer

Answer: C. 1.6 × 10³/µL

Absolute count = total WBC × the percentage as a decimal: 8.0 × 0.20 = 1.6 × 10³/µL (1,600/µL). A (0.16) moves the decimal one place too far. B (16.0) multiplies by 2 instead of 0.20. D (2.5) comes from dividing 20 by 8, which is not how an absolute count is calculated.

Source Clinical Hematology, White Blood Cells, Merck Veterinary Manual

Question 2A cat's analyzer platelet count is 45,000/µL. On the blood smear, you find large platelet clumps at the feathered edge. What should you report to the veterinarian?

Show answer

Answer: A. The count is a minimum value, and clumps are present

Platelet clumps lower the platelet count by any method, so the reported count is a minimum, and the clumps must be reported with it. Cats are notorious for clumping. B ignores the clumps, so thrombocytopenia is not confirmed. C is wrong because large platelets do not make a low count normal. D is wrong because heparin makes cells clump and is not recommended for cell counts.

Source Platelet count, eClinPath, Cornell University

Question 3Your wedge smears keep running all the way to the end of the slide with no feathered edge. Which change is most likely to fix this?

Show answer

Answer: D. Use a smaller drop, a steeper angle and a faster push

Cornell lists a smaller drop, a steeper spreader angle and a faster push as the cures for a smear that is too long with no feathered edge. A makes the smear longer, not shorter. B lowers the angle, which lengthens the smear, and heavy downward force causes waves and ridges. C is wrong because refrigerated blood (Bellwood, Today's Veterinary Nurse) should be warmed to room temperature before a smear is made, since cells clump in cold samples.

Source Samples for Hematology, Common blood smear faults and their cures, Cornell University Animal Health Diagnostic Center

Question 4You spin a microhematocrit tube from a healthy adult horse at a wellness visit. The plasma is clear but distinctly yellow. How should you record this?

Show answer

Answer: B. Normal plasma color for this species, recorded as seen

Merck states that equine and bovine plasma is normally yellow; in other species any yellow color is abnormal. Record the color as seen and do not label it icteric on color alone. A applies to yellow plasma in a dog or cat. C is wrong because lipemia looks hazy to milky white, not clear yellow. D is wrong because hemolysis makes plasma pink to red.

Source Clinical Biochemistry, Point-of-Care Tests, Merck Veterinary Manual

Question 5You estimate platelets on a dog's smear. Over 10 oil-immersion fields of the monolayer you average 9 platelets per field, with no clumps. Using the usual multiplier, what is the estimate?

Show answer

Answer: C. About 135,000/µL, below the Merck dog range

Estimated platelets/µL = average per 100× oil field × 15,000, so 9 × 15,000 = 135,000/µL. The Merck dog range is 211,000 to 621,000/µL, so the estimate is low. A forgets the multiplier. B has the right number but the wrong comparison. D multiplies by 150,000 instead of 15,000.

Source Platelet count, Platelet count estimates from a blood smear examination, eClinPath, Cornell University

0 of 5 answered

Practise this topic

Two questions from our VTNE practice bank on this topic.

Question 1When evaluating a wedge blood smear, which area of the smear should be used to perform the differential leukocyte count for the most accurate and representative results?

Show answer

Answer: B. The monolayer just behind the feathered edge

The monolayer is the area where cells are examined in close detail and the differential count is performed. It usually sits about one 10x field behind the feathered edge, where cells are well spread, not overlapping, and not disrupted because the area dries quickly. The platelet estimate is also done in the monolayer.

The thick body of the smear dries too slowly for leukocytes to spread out, so cells are too crowded to identify at high power. The feathered edge should be scanned first at low power for platelet clumps, microfilariae and large abnormal cells, but its leukocytes are excessively spread and look larger than they are. The lateral edges are not where eClinpath directs the detailed count, and in poorly made smears leukocytes are dragged toward the end, so counting outside the monolayer biases the differential.

Source Smear Examination, eClinpath, Cornell University

Practise all 6 questions on this topic Free account. Or try the free practice quiz.

Figure credits

References

  1. Whitbread TJ. Clinical Hematology. Merck Veterinary Manual, Clinical Pathology and Procedures. merckvetmanual.com (accessed 2026-10-30) merckvetmanual.com/clinical-pathology-and-procedures/diagnostic-procedures-for-the-private-practice-laboratory/clinical-hematology
  2. Fielder SE. Hematology Reference Ranges. Merck Veterinary Manual, Reference Guides. merckvetmanual.com (accessed 2026-10-30) merckvetmanual.com/reference-values-and-conversion-tables/reference-guides/hematology-reference-ranges
  3. Cornell University College of Veterinary Medicine. Hematocrit/packed cell volume. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/tests/hematocrit/
  4. Cornell University College of Veterinary Medicine. Total Protein. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/chemistry/proteins/total-protein/
  5. Cornell University College of Veterinary Medicine. Smear examination. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/blood-smear-examination/
  6. Cornell University College of Veterinary Medicine. Platelet count. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/tests/platelet-count/
  7. Cornell University College of Veterinary Medicine. WBC counts. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/tests/wbc-count/
  8. Cornell University College of Veterinary Medicine. MCV. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/tests/mean-cell-volume/
  9. Cornell University College of Veterinary Medicine. Hemogram basics. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/hematology/hemogram-basics/
  10. Cornell University Animal Health Diagnostic Center, Clinical Pathology Laboratory. Samples for Hematology. vet.cornell.edu (accessed 2026-10-30) vet.cornell.edu/animal-health-diagnostic-center/laboratories/clinical-pathology/samples-submissions/samples-hematology
  11. Bellwood B. Manual Blood Smear Preparation and Review. Today's Veterinary Nurse. Spring 2025. todaysveterinarynurse.com (accessed 2026-10-30) todaysveterinarynurse.com/hematology/manual-blood-smear-preparation-and-review/
  12. Claude R, Walton SA. Simple, Practical, and Inexpensive Veterinary Diagnostics. Today's Veterinary Practice. January/February 2023. todaysveterinarypractice.com (accessed 2026-10-30) todaysveterinarypractice.com/diagnostics/simple-practical-and-inexpensive-veterinary-diagnostics/
  13. Whitbread TJ. Clinical Biochemistry. Merck Veterinary Manual, Clinical Pathology and Procedures. merckvetmanual.com (accessed 2026-10-30) merckvetmanual.com/clinical-pathology-and-procedures/diagnostic-procedures-for-the-private-practice-laboratory/clinical-biochemistry
  14. Papajeski B. Measuring Urine Specific Gravity With a Clinical Refractometer. Today's Veterinary Nurse. Winter 2023. todaysveterinarynurse.com (accessed 2026-10-30) todaysveterinarynurse.com/clinical-pathology/measuring-urine-specific-gravity-with-a-clinical-refractometer/
  15. Cornell University College of Veterinary Medicine. Interference indices. eClinPath. eclinpath.com (accessed 2026-10-30) eclinpath.com/chemistry/interference-indices/
  16. American Association of Veterinary State Boards. 2023 Veterinary Technician National Examination Content Outline. aavsb.org (accessed 2026-10-30) aavsb.org/wp-content/uploads/2025/04/AAVSB-2023-Veterinary-Technician-National-Examination-Content-Outline-2.pdf
  17. Oliva D, Lardé H, Bouillon J, et al. Estimation of minimum centrifugation time of microhematocrit tubes to obtain accurate results of packed cell volume and total solids in donkeys, dogs, sheep, and cows. J Vet Diagn Invest. 2025. PMC12378263 pmc.ncbi.nlm.nih.gov/articles/PMC12378263/
  18. University of Minnesota. Module 1.1: General Laboratory Safety. Clinical Veterinary Diagnostic Laboratory (open textbook). pressbooks.umn.edu (accessed 2026-10-30) pressbooks.umn.edu/cvdl/chapter/chapter-1/
  19. Occupational Safety and Health Administration. 29 CFR 1910.1030, Bloodborne pathogens. osha.gov (accessed 2026-10-30) osha.gov/laws-regs/regulations/standardnumber/1910/1910.1030

Spotted an error? Email support@vtneexam.com and we will check it against the sources.