Exam 1: Blood tubes, Retic's

Question 1

Red Top tube uses

Answer 1

small animal SERUM chem panel (no plasma)
body fluids for chem or culture
(1-2 ml required)

Question 2

What’s in a red top?

Answer 2

no anticoagulant

Question 3

Tiger top uses

Answer 3

small animal serum chemistry

Question 4

What’s in a tiger top?

Answer 4

• Gel to separate serum and RBC’s to prevent re-mixing

- no anticoagulant

Question 5

Purple top uses

Answer 5

CBC
body fluids
cytologic analysis

Question 6

What’s in a purple top?

Answer 6

• EDTA anticoagulant (w/ potassium salts chelate Calcium)
• preserves cell morphology, inhibits bacterial growth
• tube must be filled at least half full

Question 7

Blue top uses

Answer 7

Coagulation testing

Platelet counts

Question 8

What in a blue top?

Answer 8

• Sodium citrate anticoagulant (weakly chelates Ca)

- MUST have 9:1 blood: citrate ratio for accurate results

Question 9

Green top uses

Answer 9

Large animal, avian, or reptile serum chem panels

or specific tests (e.g. lead concentration)

Question 10

What’s in a green top?

Answer 10

• Heparin anticoagulant (to prevent thrombin from promoting fibrin formation)
• Gives plasma readings (vs. serum)

Question 11

Grey top tube uses

Answer 11

Shipping whole blood but can’t spin sample down

Question 12

What’s in a grey top?

Answer 12

Sodium fluoride to inhibit glu metabolism

Question 13

What order to fill blood tubes?

Answer 13

1. Citrate
2. Serum
3. EDTA

Question 14

How soon should you analyze your CBC?

Answer 14

• within 1 hour
• or make blood film asap and refrigerate tube
• don’t freeze, don’t leave at room temp over 24 hrs

Question 15

Process for analyzing serum

Answer 15

• allow clotting 15-30 min, then centrifuge
• separate serum & refrigerate
• ideally analyze within 24 hrs, up to 48 hrs

Question 16

Tissue contamination of sample

Answer 16

get platelet activation –> clot

Erroneously low platelet count

Question 17

Wrong blood:anticoag ratio in purple top

Answer 17

Underfilled = excess EDTA –> shrinks RBC’s

erroneously low PCV & MCV

Question 18

Wrong blood:anticoag ratio in blue top

Answer 18

prolonged time to coagulation (inaccurate for testing)

Question 19

What happens if blood left at room temp >24 hrs?

Answer 19

RBC swelling –> increased MCV

some enzymes will have artifically low activity

Question 20

Artifacts that could be due to sample handling

Answer 20

Altered CBC number
Deterioration of WBC morphology
RBC shrinkage, swelling, or hemolysis
Prolonged coag times
altered serum chem values

Question 21

Reticulocyte

Answer 21

• young/immature erythrocyte
• Polychromatophil aka bluer on Wright’s stain because still contains ribosomes/mitochondria in cytoplasm
• Special stain shows residual organelle aggregation

Question 22

How to do a reticulocyte enumeration

Answer 22

1. EDTA blood + blue stain mixed
2. incubate 10 min
3. make blood film and count 1000 RBC’s
4. categorize as reticulocyte or normal RBC
5. Find % reticulocytes present, calculate ARC

Question 23

ARC

Absolute reticulocyte count

Answer 23

ARC = RBC/microliter x % reticulocyte

Question 24

What is the point of a reticulocyte enumeration?

Answer 24

• Helps determine if anemia is regenerative or not

- increased retic count = regenerative

Question 25

Reticulocyte normal circulation per spp

Answer 25

• Dogs/cats - normal to circulate (higher rates in dogs)
• Cows - can circulate, but 0 circulation in health
• EQ - DONT release reticulocytes from bone marrow even with regeneration

Question 26

Reticulocyte time to maturation

Answer 26

Dogs - 24-48 hrs

Cats - Aggregate becomes punctate in 12 hrs, Punctate matures in 10-12 days
(Aggregate is counted for retic count, not punctate)