Healthy Animals Block 8 Exam: Hematopoiesis

3 kinds of laboratory errors

• pre-analytical

• analytical

• post-analytical

Where do most laboratory errors occur?

Pre-analytical account for 52-77% of all errors

How can you avoid pre-analytical errors?

• correct patient and test

• proper sample collection

• proper labeling, storage, and transport

How can you avoid analytical errors?

• sample processing

• correct analyzer and method

• quality control and assurance

How can you avoid post-analytical errors?

• results recorded correctly

• correct reference intervals

• correct interpretation

pre-analytical error definition

• occur prior to sample testing

• ex: test selection and ordering, sample collection and handling, sample identification, sample transport

analytical error definition

• occurs during sample analysis

• ex: equipment malfunction, reagent expiration and degeneration, pipetting errors, interfering substances

post-analytical error definition

• occurs after results are generated

• ex: transcription errors, failure to report test results, improper delivery of test results, misinterpretation of results

What is hematopoiesis responsible for?

regenerates RBC, WBC, and platelets through hematopoietic stem cells

Where does hematopoiesis occur?

in bone marrow of flat bones and ends of long bones

What are required for normal hematopoiesis?

• hematopoietic stem cells

• growth factors

• bone marrow microenvironment

During hematopoiesis what do stem cells divide into?

divide into more stem cells to self renew or become committed progenitor cells to become blood cells

Where does extramedullary hematopoiesis occur?

liver and spleen

Where can hematopoiesis occur in non-mammalian species?

• bone marrow

• spleen

• liver

• kidney

• lung

• and more

histology of hematopoietic tissue

• hematopoietic cells

• stromal tissue (fat, fibrous tissue)

• vascular sinuses

What do myeloid progenitors become?

• RBCs

• granulocytes

• monocytes

• platelets

What do lymphoid progenitors become?

• B cells

• T cells

• NK cells

Erythropoiesis definition

production of RBCs from hematopoietic progenitor cells

What is needed for erythropoiesis?

• iron from macrophages within erythroid islands

• erythropoietin from kidney

What happens to characteristics of cells to make RBC during erythropoiesis

• cell size decrease

• nuclear size decrease

• chromatin condensation increase

• nuclei extruded from cell

• cytoplasm becomes less basophilic

What is name change of cells during erythropoiesis?

1. rubriblast

2. prorubricyte

3. rubricyte

4. metrubricyte

5. polychromatophil

6. mature RBC

How long does it take for rubriblast to become RBC?

7 days

What does granulopoiesis produce from common myeloid progenitors?

• neutrophils

• eosinophils

• basophils

What happens to characteristic of cells during granulopoiesis?

• size decrease

• chromatin condenses

• nucleus becomes segmented

How long does it take for cells to mature during granulopoiesis?

5-7 days

What is name change of cells during granulopoiesis?

1. myeloblast

2. promyelocyte

3. myelocyte

4. metamyelocyte

5. band

6. mature

proliferating pool cells in bone marrow

• myeloblasts

• progranulocytes

• myelocytes

maturation and storage pool cells

• metamyelocytes

• bands

• segmented neutrophils

What cells does thrombopoiesis make?

megakaryocyte

What is name change of cells during thrombopoiesis?

1. megakaryoblast

2. promegakaryocyte

3. megakaryocyte

What happens to the nucleus during thrombopoiesis?

it does not divide

How are platelets formed during thrombopoiesis?

• megakaryocytes produce cytoplasmic extensions that form platelets

• regulated by thrombopoietin

What cells are made during lymphopoiesis?

• B lymphocytes

• T lymphocytes

• Natural killer cells

• from common lymphoid progenitors

What cells are made during monopoiesis?

• monocytes

  • further differentiate into cells like macrophages, dendritic cells, Langerhans cells

• from common myeloid progenitors

What is part of a CBC?

• plasma protein

• erythrogram

• leukogram

• thrombogram

• microscopic blood smear review

What does an erythrogram measure?

• RBC count

• HCT or PCV

• hemoglobin

• mean corpuscular volume MCV

• mean corpuscular hemoglobin concentration MCHC

• cellular hemoglobin concentration mean CHCM

• reticulocytes

What does a leukogram measure?

• total nucleated cell count TNCC or WBC

• WBC differential (percent and absolute count)

  • neutrophil

  • lymphocyte

  • monocyte

  • eosinophil

  • basophil

What does a thrombogram measure?

• platelet count

• MPV

What is included in collection and sample handling when getting a CBC?

• clean venipuncture with minimal excitation

• use syringe and needle or vacutainer system

• get volume sufficient for test

• use minimal force while collecting blood and filling tube

EDTA/lavender top tube

• preferred anticoagulant for CBC in mammals

• binds Ca2+

Heparin/green top tube

• used for CBCs in non-mammalian species

• potentiates antithrombin III

sodium citrate/blue top tube

• coagulation test

• binds Ca2+

How does centrifuged anticoagulated blood separate in EDTA tube?

• top = plasma

  • water, proteins, lipids

• middle = buffy coat

  • platelets and WBC

• bottom = RBC

What is role of RBC?

• carry oxygen to cells

• remove carbon dioxide from tissues

• circulate back to lungs for more oxygen

Why are RBCs red?

hemoglobin that requires iron

What is the oxygen carrying molecule in RBCs?

hemoglobin

What is a con of using bench top instruments for automated hematology analyzers?

not as accurate in sick animals

What are the two common stains for blood smears?

• Wright’s stain

• quick stain (Diff-quick)