Erythrogram & Anemia

Question 1

What is RBC?

Answer 1

**RBC = Red Blood Cell count

Number of RBCs per unit of blood, M/microliter; impedance count

Question 2

What is Hemoglobin (Hgb)?

Answer 2

Hemoglobin = the protein within RBCs that carries O2

Concentration measured in g/dL; should = 1/3 PCV%

Each heme subunit of Hgb contains an iron (Fe) molecule

Question 3

What are Hematocrit (Hct) and Packed Cell Volume (PCV), and how are they different?

Answer 3

Both = the % of blood volume filled by RBCs

Differ in how they are measured (Hct = analyzer) (PCV = microhematocrit tube + centrifuge)

Question 4

What do RBC indices measure?

Answer 4

The size, shape and quality of RBCs present

Question 5

What are the two factors of RBC indices?

Answer 5

Mean Corpuscular (Cell) Volume (MCV) of circulating RBCs

Mean Corpuscular (Cell) Hgb concentration (MCHC) within circulating RBCs

MCHC measured in g/dL

MCV measured in femtolitres (fL)

Question 6

Describe the separation that occurs in a microhematocrit tube after centrifuging.

Answer 6

The plasma (anticoagulated/free-fluid part) and the serum (PCV part) are separated to top and bottom, respectively.

Question 7

Increased PCV or Hct is called what?

Answer 7

Erythrocytosis = Polycythemia

Question 8

What can cause increased PCV?

Answer 8

Dehydration

Question 9

Decreased PCV or Hct is called what?

Answer 9

Anemia

Question 10

Dog: PCV ≥ 33%
Cat: PCV ≥ 26%

Answer 10

Patients are mildly anemia

Question 11

Dog: PCV ≥ 24%
Cat: PCV ≥ 23%

Answer 11

Patients are moderately anemic

Question 12

Dog: PCV ≤ 23%
Cat: PCV ≤ 23%

Answer 12

Patients are markedly anemic

Question 13

What can artifactually increase or decrease PCV?

Answer 13

Sample storage (increase PCV%)

Hemolysis (decrease PCV %)

Question 14

What can artifactually decrease Hct?

Answer 14

Hemolysis (decrease Hct)

Question 15

What can artifactually decrease RBC?

Answer 15

Sample storage

RBC agglutination

Question 16

What is the difference between a reticulocyte and an erythrocyte?

Answer 16

Two days after a reticulocyte (immature RBC) forms, it develops into an erythrocyte (mature RBC)

Question 17

What is an indicator of erythroid regeneration?

Answer 17

Increased reticulocyte # in blood

Question 18

What colors do reticulocytes versus erythrocytes routinely stain?

Answer 18

Reticulocytes: blue (polychromatic)
Erythrocytes: pink

Question 19

What type of feline reticulocyte are the red arrows pointing to?

Answer 19

Punctate Reticulocytes (1-3 weeks)

Question 20

What type of feline reticulocyte are the white arrows pointing to?

Answer 20

Aggregate Reticulocytes (1-2 days)

Question 21

When does polychromasia occur on a routine stain?

Answer 21

Occurs when RBCs are released too early from the bone marrow (a.k.a. immature//reticulocytes)

Question 22

What is an appropriate response to anemia?

Answer 22

Regenerative Anemia: increased polychromatophilic RBCs in peripheral blood (reticulocytosis)

Question 23

What species are reticulocytes not released in?

Answer 23

Equines

Question 24

What is the cutoff range for regenerative anemia in dogs/cats?

Answer 24

Dog = greater than 80,000 per microliter

Cat = greater than 60,000 per microliter

Question 25

Which type of feline reticulocyte is indicative of ACTIVE RBC regeneration?

Answer 25

Aggregate

Question 26

What are metarubricytes?

Answer 26

Nucleated RBCs (nRBCs) / the stage of RBCs that directly precedes the reticulocyte stage

Question 27

True or False: increased nRBC numbers (metarubricytosis) are always indicative of regenerative anemia

Answer 27

False

increased nRBC numbers may accompany regeneration

Question 28

When is metarubricytosis considered appropriate?

Answer 28

When it occurs concurrently with regenerative anemia.

Question 29

When is metarubricytosis considered inappropriate?

Answer 29

When it occurs in the absence of reticulocytosis (regenerative anemia)

Question 30

What types of diseases or situations can cause inappropriate metarubricytosis?

Answer 30

• damage to the membranes that separate the hematopoietic spaces from the marrow spaces (due to heat stroke, heavy metal toxicity, hypoxemic bone marrow injury [severe anemia], infection)
• recent fracture or orthropedic sx
• splenic disease or injury (spleen clears nRBCs)
• errythroid leukemia (cats)

Question 31

Why won’t you typially see nRBC value on a CBC?

Answer 31

Because the normal, healthy nRBC range is very low; will only appear if value is high

Question 32

What is macrocytic anemia and how does it appear on a CBC?

Answer 32

Enlarged RBCs
Elevated MCV (due to agglutination)

Question 33

What is microcytic anemia and how does it appear on a CBC?

Answer 33

Shrunken RBCs
Decreased MCV, MCHC

Decreased MCHC = hyprochromic

Question 34

What artifacts can cause microcytic anemia?

Answer 34

• Short draws (low blood volume collected in sample)
  –> excess EDTA to blood ratio
• Hyponatremia (low serum Na levels)

Hyponatremia most offen occurs when the body retains water as an attempt to preserve electrolytes, especially after v+ or d+ episodes.

Question 35

What artifacts can cause macrocytic anemia?

Answer 35

• RBC agglutination
• Sample storage
• Hypernatremia
• Hyperglycemia

Hypernatremia is caused by inadequate water intake (can be life-threatening if px is markedly hypernatremic)

Hyperglycemia = elevated BG

Question 36

What is hyperchromic anemia and how does it appear on a CBC?

Hyperchromic Anemia is NOT real, and is a result of technical artifact!

Answer 36

Elevated Hgb levels
Elevated MCHC

Elevated MCHC indicates an excess amount of hemoglobin, but RBCs can’t have ‘excess’ hemoglobin, so it usually implies free hemoglobin in plasma.

Question 37

What is hypochromic anemia and how does it appear on a CBC?

Answer 37

Decreased Hgb levels
Decreased MCHC

Question 38

What is the #1 pathological cause of microcytic anemia?

Answer 38

Iron deficiency

Causes insufficient Hgb concentration, which causes an extra rubricyte division cycle to occur, producing shrunken RBCs

Question 39

What are some examples of technical artifacts that result in hyperchromic anemia?

Answer 39

• short draws
• hemolysis
• lipemia

This is a result of a traumatic blood draw (with rupture of RBCs and release of hemoglobin) or intravascular hemolysis (due to a problem with the RBCs, e.g. oxidative injury, immune mediated damage, RBC infectious agents)

Question 40

What are some pathologic causes of hypochromic anemia?

Answer 40

• Iron deficiency
• Reticulocytosis
• Liver disease

Question 41

What are key clues that support macrocytic, hypochromic anemia?

Answer 41

Reticulocytosis

Regenerative anemias can also be macrocytic, normochromic or normocytic, hypochromic – so it is the reticulocyte count that is most important!

Question 42

What are key clues that support microcytic, hypochromic anemia?

Answer 42

Iron deficiency

Question 43

Why is hypoplasia (atrophy) considered non-regenerative anemia?

Answer 43

Because there is a lack of cells in the bone marrow that can produce/develop into new RBCs

Erythroid hypoplasia – bone marrow is not responding to a peripheral need for RBCs

Question 44

Why are hemorrhages and hemolysis considered regenerative anemia?

Answer 44

Blood loss signifies a need for more RBCs

Erythroid hyperplasia – appropriate bone marrow response to peripheral need for RBCs (e.g. blood loss resulting in a decrease in peripheral tissue oxygen tension)

Question 45

What are signs of anemia in an animal?

Answer 45

Pale mucous membranes, tachycardia, exercise intolerance