Erythrogram & Anemia Flashcards by Kate Karlen

What is RBC?

**RBC = Red Blood Cell count

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

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What is Hemoglobin (Hgb)?

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

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

Both = the % of blood volume filled by RBCs

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

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What do RBC indices measure?

The size, shape and quality of RBCs present

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What are the two factors of RBC indices?

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)

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

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

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Increased PCV or Hct is called what?

Erythrocytosis = Polycythemia

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What can cause increased PCV?

Dehydration

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Decreased PCV or Hct is called what?

Anemia

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Dog: PCV ≥ 33%
Cat: PCV ≥ 26%

Patients are mildly anemia

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Dog: PCV ≥ 24%
Cat: PCV ≥ 23%

Patients are moderately anemic

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Dog: PCV ≤ 23%
Cat: PCV ≤ 23%

Patients are markedly anemic

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What can artifactually increase or decrease PCV?

Sample storage (increase PCV%)

Hemolysis (decrease PCV %)

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What can artifactually decrease Hct?

Hemolysis (decrease Hct)

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What can artifactually decrease RBC?

Sample storage

RBC agglutination

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What is the difference between a reticulocyte and an erythrocyte?

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

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What is an indicator of erythroid regeneration?

Increased reticulocyte # in blood

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What colors do reticulocytes versus erythrocytes routinely stain?

Reticulocytes: blue (polychromatic)
Erythrocytes: pink

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

Punctate Reticulocytes (1-3 weeks)

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

Aggregate Reticulocytes (1-2 days)

When does polychromasia occur on a routine stain?

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

What is an appropriate response to anemia?

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

What species are reticulocytes not released in?

Equines

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

Dog = greater than 80,000 per microliter

Cat = greater than 60,000 per microliter

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

Aggregate

What are **metarubricytes**?

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

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

False | increased nRBC numbers may **accompany** regeneration

When is metarubricytosis considered **appropriate**?

When it occurs **concurrently** with regenerative anemia.

When is metarubricytosis considered **inappropriate**?

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

What types of **diseases or situations** can cause inappropriate metarubricytosis?

- 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)

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

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

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

**Enlarged** RBCs **Elevated** MCV (due to agglutination)

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

**Shrunken** RBCs **Decreased** MCV, MCHC ## Footnote Decreased MCHC = hyprochromic

What **artifacts** can cause microcytic anemia?

* **Short draws** (low blood volume collected in sample) --> excess EDTA to blood ratio * **Hyponatremia** (low serum Na levels) ## Footnote Hyponatremia most offen occurs when the body retains water as an attempt to preserve electrolytes, especially after v+ or d+ episodes.

What **artifacts** can cause macrocytic anemia?

* **RBC agglutination** * **Sample storage** * **Hypernatremia** * **Hyperglycemia** ## Footnote Hypernatremia is caused by inadequate water intake (can be life-threatening if px is markedly hypernatremic) Hyperglycemia = elevated BG

What is **hyperchromic anemia** and how does it appear on a CBC? | Hyperchromic Anemia is NOT real, and is a result of technical artifact!

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

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

**Decreased** Hgb levels **Decreased** MCHC

What is the #1 **pathological** cause of **microcytic anemia**?

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

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

* short draws * hemolysis * lipemia ## Footnote 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)

What are some **pathologic causes** of **hypochromic anemia**?

* **Iron deficiency** * **Reticulocytosis** * Liver disease

What are key clues that support **macrocytic**, **hypochromic anemia**?

Reticulocytosis ## Footnote Regenerative anemias can also be macrocytic, normochromic or normocytic, hypochromic -- so it is the **reticulocyte count** that is most important!

What are key clues that support **microcytic**, **hypochromic anemia**?

Iron deficiency

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

Because there is a **lack of cells in the bone marrow** that can produce/develop into new RBCs ## Footnote Erythroid hypoplasia – bone marrow is not responding to a peripheral need for RBCs

Why are **hemorrhages** and **hemolysis** considered **regenerative anemia**?

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

What are **signs of anemia** in an animal?

Pale mucous membranes, tachycardia, exercise intolerance