Laboratory Errors, Hematopoiesis, and Blood Cell Analysis in Veterinary Medicine

What are the three types of laboratory errors?

Pre-analytical, Analytical, Post-analytical.

What is a pre-analytical error?

Error before testing (e.g., wrong test, sample mishandling).

What is an analytical error?

Error during analysis (e.g., equipment malfunction, expired reagents).

What is a post-analytical error?

Error after results (e.g., transcription errors, misinterpretation).

What is hematopoiesis?

Process of forming blood cells from stem cells.

Where does hematopoiesis occur in adults?

Bone marrow.

What is erythropoiesis?

Production of red blood cells (RBCs).

What hormone regulates erythropoiesis?

Erythropoietin (EPO).

What is myelopoiesis?

Production of non-lymphoid white blood cells.

What is thrombopoiesis?

Production of platelets.

What regulates thrombopoiesis?

Thrombopoietin (TPO).

What blood tube is used for CBC?

Lavender top tube (EDTA).

What does EDTA do?

Prevents clotting and minimizes platelet clumping.

What is the primary cytokine for erythropoiesis?

Erythropoietin (EPO).

What element is essential for erythropoiesis?

Iron (Fe).

What do RBCs do?

Carry oxygen and remove carbon dioxide.

How are RBCs evaluated?

Through an erythrogram and blood smear.

What is hematocrit (HCT)?

Percentage of blood volume composed of RBCs.

What does the reticulocyte count indicate?

Bone marrow's response to anemia.

What is Mean Corpuscular Volume (MCV)?

Average size of RBCs.

What does MCHC measure?

Average hemoglobin concentration in RBCs.

What does RDW measure?

Variation in RBC size (anisocytosis).

What is the maturation sequence of RBCs?

Rubriblast → Prorubricyte → Rubricyte → Metarubricyte → Reticulocyte → Mature RBC.

What happens during RBC maturation?

Cell size decreases, nucleus condenses, cytoplasm changes.

What is the maturation sequence of megakaryocytes?

Megakaryoblast → Promegakaryocyte → Megakaryocyte.

How long do platelets circulate?

About 5-7 days.

Why is microscopic review important?

Automated instruments miss many abnormal RBC shapes.

What is rouleaux?

Normal arrangement of RBCs in horses/cats.

What does agglutination indicate?

Clumping due to antibody coating, often in IMHA.

What is polychromasia?

Bluer, immature RBCs indicating regeneration.

What is hypochromasia?

Increased central pallor, suggests iron deficiency.

What are spherocytes?

Smaller cells lacking central pallor, suggest IMHA.

What are Heinz bodies?

Protrusions of oxidized hemoglobin from toxins/drugs.

What are schistocytes?

RBC fragments from mechanical trauma or vascular disease.

What are target cells?

Floppy cells with a 'bullseye' appearance, seen in liver disease.

What are eccentrocytes?

Cells with hemoglobin pushed to one side due to oxidative damage.

Why mix blood samples before CBC?

Prevents cellular settling and ensures homogeneity.

What does hematocrit measure?

Percentage of blood volume composed of RBCs.

What does hemoglobin indicate?

Oxygen-carrying capacity of blood.

What is RBC count?

Actual number of RBCs in a specific blood volume.

What does MCV measure?

Average size of RBCs.

What does MCHC indicate?

Average hemoglobin concentration in RBCs.

What does reticulocyte count indicate?

Bone marrow response to anemia.

What is regenerative anemia?

Increased reticulocyte count, indicates bone marrow response.

What is non-regenerative anemia?

Normal reticulocyte count, indicates no bone marrow response.

What stain is used for blood smears?

Wright-Giemsa stain or Diff-Quik.

What stain identifies Heinz bodies?

New Methylene Blue (NMB).

What is the difference between PCV and HCT?

PCV is manual; HCT is calculated by analyzers.

What measures red blood cell size and volume?

Automated analyzer

What percentage indicates anemia?

Decrease in hematocrit or red blood cell mass

What is the proliferating pool?

Active granulocyte production in bone marrow

What cells are in the proliferating pool?

Myeloblasts, Progranulocytes, Myelocytes

What happens in the maturation and storage pool?

Cells develop, no longer divide

What are non-dividing cells in the maturation pool?

Metamyelocytes, band neutrophils, segmented neutrophils

Normal transit time for cell maturation?

7 to 10 days

What speeds up cell production during inflammation?

Decreased transit time

What regulates the proliferating pool?

Cytokines, Growth Factors

What are platelets derived from?

Megakaryocytes

What is the mechanism of platelet formation?

Fragmentation of cytoplasmic extensions

What hormone regulates thrombopoiesis?

Thrombopoietin (TPO)

What is primary absolute erythrocytosis?

Uncontrolled RBC production independent of EPO

What causes primary erythrocytosis?

Bone marrow disorder (e.g., Polycythemia Vera)

What are EPO levels in primary erythrocytosis?

Normal to decreased

What is secondary absolute erythrocytosis?

Normal marrow, increased EPO levels

What triggers appropriate secondary erythrocytosis?

Systemic hypoxia

What are causes of appropriate secondary erythrocytosis?

Heart disease, high altitude

What indicates inappropriate secondary erythrocytosis?

High EPO with normal oxygen levels

What causes inappropriate secondary erythrocytosis?

Diseased kidney, tumors

What causes Primary Polycythemia Vera?

Bone marrow mutation

What causes Secondary Polycythemia (Appropriate)?

High EPO due to hypoxia

What causes Secondary Polycythemia (Inappropriate)?

High EPO from disease/tumor

EPO levels in Primary Polycythemia Vera?

Normal to Decreased

EPO levels in Appropriate Secondary Polycythemia?

Increased

EPO levels in Inappropriate Secondary Polycythemia?

Increased

Oxygen levels in Primary Polycythemia Vera?

Normal

Oxygen levels in Appropriate Secondary Polycythemia?

Decreased

Oxygen levels in Inappropriate Secondary Polycythemia?

Normal

Frequency of Primary Polycythemia Vera?

Rare

Frequency of Appropriate Secondary Polycythemia?

Common

Frequency of Inappropriate Secondary Polycythemia?

Less common than appropriate

What is External Hemorrhage?

Blood loss from body

Total Protein in External Hemorrhage?

Decreased

PCV in External Hemorrhage?

Decreased

What is Internal Hemorrhage?

Blood loss into cavities

Total Protein in Internal Hemorrhage?

Normal or Mildly Decreased

Bilirubin in Internal Hemorrhage?

Increased

Examples of External Hemorrhage?

Lacerations, GI ulcers

Examples of Internal Hemorrhage?

Splenic tumors, body cavities

What is Anemia of Chronic Disease (ACD)?

Non-regenerative anemia from inflammation

Severity of ACD?

Mild to moderate

Regeneration in ACD?

Non-regenerative

RBC Indices in ACD?

Normocytic, normochromic

Leukogram in ACD?

Inflammatory leukogram

Pathogenesis of ACD?

Inflammatory cytokines suppress EPO

What is Functional Iron Deficiency?

Iron trapped in macrophages

Resolution of ACD?

Treat primary disease

WBC Count in ACD?

Often increased

Iron Stores in ACD?

Increased

What is Iron Deficiency Anemia (IDA)?

Depleted iron stores

Resolution of IDA?

Stop blood loss/add iron