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Veterinary Clinical Pathology > Intro and Laboratory Principles > Flashcards

Flashcards in Intro and Laboratory Principles Deck (51)
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1

What is Clinical Pathology?

Hematology, clinical chemistry, exfoliative cytology, urinalysis, endocrinology, clinical immunology, toxicology

2

Reasons for testing

health screen, screen for disease, identify specific organ involvement, confirm presumptive diagnosis, confirm abnormal test, determine disease severity, formulate prognosis, monitor therapy or disease progression

3

Understanding reference intervals

2.5% of the healthy population will have values beyond either side of the median 95% and be deemed "abnormal" even though they are fine; is a compromise that increases the sensitivity of the test for recognizing sick animals because only a few healthy animals will be viewed as "abnormal"

4

What is the chance of an abnormal test result when testing a healthy animal?

5% chance when 1 analyze measured; 64% chance when 20 analytes measured

5

Factors affecting reference intervals

species, age, sex, time postprandial, time of day, emotional state, activity level, pregnancy/egg-laying, diet, region, time of year, generally collect overnight fasting samples from adult animals to increase chances of "normal"

6

Most common laboratory error

pre-analytical - ie. improper handling of samples (labeling), wrong anticoagulant/improper ratio of anticoagulant, traumatic blood draw or transfer of blood into tubes causing hemolysis

7

Blood samples getting old cause what cellular changes? and these changes affect what blood cell measurements.?

cell lysis
erythrocyte swelling -> affects MCV, MCHC, PCV
platelet activation -> affects MPV and platelet count

8

Platelet, leukocyte, and erythrocyte clumps could affect which blood cell measurements?

number/microliter blood decreased
platelets counted as leukocytes
MCV, MCHC, electronic HCT
MPV increased

9

What additive helps with platelet and leukocyte clumping?

citrate

10

Clot formation affects what blood cell measurements

all cell types decrease

11

Purple top tubes have what additive?

EDTA

12

Green top tubes have what additive?

Lithium heparin

13

Blue Top tubes have what additive?

citrate

14

What interfering substances cause analytical errors?

hemolysis, lipemia, hyperbilirubinemia

15

Falsely elevated potassium concentrations in horses and cattle can be due to what laboratory error/cellular process?

hemolysis - they have high K in RBCs

16

What three visual factors do you need to evaluate before examining blood samples?

color - tomato soup vs. syrump (methemoglobinemia)
Agglutination vs. rouleaux -if rouleaux you can use saline 10:1 to separate
is it mixed well?

17

Define rouleaux

"stack of coins" - due to non-specific binding of RBCs due to high protein content in the blood, will disperse with saline

18

Define agglutination

clumping of RBCs due to specific binding of RBCs by antibodies when IMHA is happening, will not disperse with saline test

19

What conditions cause lipemia in blood samples?

When animals not fasted before blood collection or with hyperlipidemic syndromes

20

How does lipemia affect blood samples?

causes turbidity
can interfere with anything that is measured by spectrophotometric assays
can dilute out normal substances like electrolytes in the aqueous component of the serum resulting in falsely decreased concentration (ion exclusion effect)

21

Give an example of a post-analytical laboratory error.

Error in data transcription

22

What are the four components of a microhematocrit tube after spinning?

plasma, buffy coat, packed red blood cells, wax plug

23

Three conditions that affect the appearance of the plasma in a microhematocrit tube?

hemolysis, lipemia, icterus

24

What types of cells are in the buffy coat?

leukocytes and platelets

25

What is fibrinogen and why is it important?

acute phase protein, precursor to fibrin in coagulation - important because it increases with inflammation so it can indicate infection in large animals that don't have dramatic neutrophilic responses; present in plasma but not serum because it is used up in clotting process - causes optimal platelet aggregation

26

What are the functions of plasma proteins?

transport of nutrients, hormones, waste and drugs
colloid osmotic effects
acid-base
immunity
hemostasis

27

Where are most plasma proteins synthesized?

in the liver - big problem if liver failures

28

Why do adults tend to have higher concentrations of plasma proteins than neonates?

exposure to antigens

29

What is the composition of plasma?

92% water
8% solids - nutrients, proteins, hormones/enzymes, and electrolytes

30

Functions of plasma

transport of nutrients
transport of by-products and waste
transportation of cells
maintain homeostasis (pH, temp, etc.)