Intro to Hematology

Question 1

“QUATS”

Answer 1

• Lingo that denotes the following:
  
  • Packed cell volume (PCV)
  • Total Solids (TS)
  • Blood Glucose (BG)
  • Blood Urea Nitrogen (BUN)

Question 2

Importance of QUATS

Answer 2

• Quick, cage-side assessment that provides a general overview of your patients metabolic status
• Generally reserved for use on patients we suspect are healthy

Question 3

What is Packed Cell Volume

Answer 3

• Percentage of blood to plasma
• Hematocrit vs. PCV
  
  • Hct is calculated by a machine using the cell count and the average diameter of the red blood cells.
  • PCV spins the blood down and calculates the ratio

Question 4

Normal Ranges of PVC for companion animals

Answer 4

• Adult dog: 37-55%
• Puppy: 25-34%
• Adult Cat: 24-45%
• Kitten: 24-34%

Question 5

What can cause Anemia

Answer 5

• Not enough RBCs
• Causes:
  
  • Loss - hemorrhage, parasitism
  • Destruction- apoptosis
  • Inability to produce- faulty bone marrow

Question 6

What can cause polycythemia

Answer 6

• Too many RBCs
• Causes:
  
  • Overproduction
  • O₂ demand
  • Dehydration

Question 7

What color should plasma be?

Answer 7

• Transparent or straw colored (slightly yellow)
• It can come in many colors:
  
  • White/cloudy: fatty
  • Red: destroyed RBCs
  • Dark Yellow/Orange: Liver disease

Question 8

What is in Plasma?

Answer 8

• Water - largest component
• Electrolytes
• Proteins

Question 9

What is Total Solids measurement?

Answer 9

• TS is sometimes referred to as Total Protein, or Serum Total Protein
• Performed with a refractometer OR can be measured in a lab
• Refractometry is an estimate of albumin and globulin in a plasma sample since these proteins have the most effect on the refractive index

Question 10

Range for TS

Answer 10

Range: 6.5 - 8.0 g/dL

Highly variable

Question 11

What could cause high total solids

Answer 11

diabetes

infection

bacteremia

dehydration

Question 12

What would cause low TS?

Answer 12

Protein losing Renal failure

Protein losing GI disease

Liver failure

Question 13

Supplies for a PCV

Answer 13

Blood sample to be tested

Microhematocrit tube

Clay sealant

Centrifuge

Microhematocrit reader or ruler

Question 14

What Microhematocrit tube to use?

Answer 14

• Heparinized: when you are taking direct from the patient
• Non-heparinized: when you are taking from a purple top tube
• Glass: more common, easier to access for TS
• Plastic: safer, less likely to break
  
  • Some centrifuges require plastic tubes

Question 15

How to prepare a PCV?

Answer 15

• Fill tube ¾ full
  
  • Place sample horizontally to allow tube to fill via capillary action
  • Once filled, place finder over the end of the tube to prevent sample from dumping out
• Wipe tube with KimWipe to remove blood from the outside of the tube
• Seal the end of the amount of clay
• Centrifuge
• Read

Question 16

Centrifuging PCV sample

Answer 16

• Place sample with the clay on the outside
• Spin for 3-5 minutes
  
  • at 2,500 rpms

Question 17

How to read a PCV

Answer 17

• Hct Reading Card
  
  • align the top of the serum with the top line
  • Align the top of the clay with the bottom line
• Ruler
  
  • Measure top of clay to top of the serum (total sample)
  • Measure top of clay to top of red cells (packed cells)
  • Dived Packed cell by Total sample = PVC%

Question 18

Blood Glucose Metabolism

Answer 18

• Complex
• Regulated by several hormones (insulin, glucagon, cortisol)
• Euglycemia - normal
• Hyperglycemia - high
• Hypoglycemia - low
• Collect sample from vein or capillary blood from a skin prick

Question 19

Euglycemia

Answer 19

• Variable
• Range 75 - 150 mg/dL
• Most of the time ~100 mg/dL

Question 20

Hyperglycemia

Answer 20

• Physiologic:
  
  • Usually mild hyperglycemia (120 - 150 mg/dL)
  • Can be profound
    
    • >200 in acutely stressed cats on rare occasion
  • Postprandial (after food) - generally the 2-4 hours after food
  • Epinephrine mediated (Acute Stress)
  • Cortisol mediated (chronic stress) - can be seen in illness
• Pathologic:
  
  • Persistently elevated
  • Glucose in urine (glucosuria)
  • Diabetes mellitus
  • Modifications (steroids)
  • Toxins (Antifreeze)

Question 21

Hypoglycemia <75 mg/dL

Answer 21

• Spurious:
  
  • Blood sitting in tube, generally >1 hour
  • Cells are alive and consuming the glucose - particularly patients with high WBC counts
• Physiologic:
  
  • Juvenile toy breed dogs
• Pathologic:
  
  • too much insulin
    
    • gave too much
    • Pancreas makes to much
    • Toxin (xylitol/artificial sweetener)
  • To little cortisol
    
    • Hypoadrenocorticism (Addison’s Disease)

Question 22

What could cause high BUN

Answer 22

High protein diet

Kidney failure

Question 23

Where can cat owners get blood from?

Answer 23

Use the lancet to prick between the marginal ear veins and the edge of the ear

Question 24

Who can get blood from a paw pad?

Answer 24

• Both cat and dog owners
• yield excellent samples
• Use the non-weight-bearing pad (the pisiform pad) to alleviate pain, generally well tolerated in animals okay with having their feet handled.

Question 25

What could cause low BUN

Answer 25

Low protein diet Liver failure

Question 26

Kidney Function

Answer 26

* BUN is cleared renally * Once kidneys loses about 66% of their overall functions patients lose ability to concentrate urine * BUN will remain normal * Once a patient **loses 75% or more** of their kidney function, the BUN **will increase**

Question 27

What is BUN

Answer 27

* Blood Urea Nitrogen * A product of protein (Amino Acid) digestion/breakdown by the liver * BUN is cleared by the kidneys * Normal Range: * Canines- 5 - 35 mg/dL * Felines - 5 - 35 mg/dL

Question 28

Blood Smear

Answer 28

* Critial component of a complete blood count * Allows for confirmation of cell count, differential, and evaluate morphology * Allows for evaluation of some infectious agents (Cytauxzoonosis)

Question 29

Where do dog owners get blood from?

Answer 29

* The inside of the dog's ear flap often yields a more consistent sample than using the outside of the ear flap as you would in a cat. * Elbow calluses are not usually sensitive and generally yield excellent blood samples * Think skin scraping: lightly pinch and hold the callus for a few seconds before you attempt blood collection, then allow blood to bubble to form before attempting to take the sample. * Lip * Can be dangerous * best for large lip folds or for very gentle dogs * consistently yield excellent blood sample

Question 30

What are the steps for a blood smear?

Answer 30

1. Gently mix blood sample 2. Use a microhematocrit ¾ full with blood and place a 4mm drop of blood on the slide 3. Back a clean slide into the blood drop and allow to spread along edge of slide 4. maintain firm contact and push the top slide in one motion 5. Air Dry 6. Dip 10-15 seconds in Methanol (blue) 7. Dip 10-15 seconds in Eosinophilic (red) 8. Dip 10-15 seconds in Basophilic (blue/purple) 9. Rinse gently with water 10. Air Dry

Question 31

How to evaluate slide quality

Answer 31

A good quality smear should have: * A dense body; takes up about ⅔ of the entire smear and should blend smoothly into the monolayer * A well-developed feathered edge. This should have a fine, feathery appearance * A monolayer are just behind the feathered edge. If held to the light, there is a rainbow effect in this area

Question 32

What are some common errors while making blood smears?

Answer 32

* Excessive downward pressure * short slides with hesitation marks and a poorly developed feather edge and monolayer region * Slow spreading motion * long thin smears, lack dense body, thin monolayer and well-developed feathered edge * wobbling the spreader slide * due to inexperience or trying to exert pressure on the slide rather than letting it rest on the surface

Question 33

What do you need to perform a blood glucose test?

Answer 33

* Veterinary glucometer * Lancets - spring loaded device that pricks the skin