Hematology and Clinical Pathology Lecture Notes

A comprehensive set of vocabulary flashcards covering hematology basics, blood composition, CBC procedures, erythrocyte/leukocyte morphology, and common blood parasites based on the lecture notes provided lecture notes.

Hematology

The study of blood, cellular fluid, blood-forming organs (which form, store, and circulate blood), and blood diseases used for diagnosis and monitoring.

Clinical Chemistry

A subarea of clinical pathology involving the analysis of bodily fluids to assess organ function, such as kidney function profiles.

Serology

The study of blood serum and other bodily fluids, specifically focusing on antibodies.

K-9 Blood Composition

A dog's blood consists of $8\%$ whole blood, of which $45\%$ is formed elements (leukocytes, erythrocytes, thrombocytes) and $55\%$ is plasma.

Blood Volume: Dogs

$8-9\%$ of body weight.

Blood Volume: Cats

$6-7\%$ of body weight.

Quantitative Buffy Coat Analysis

An automated hematology method that measures cell widths variation and contrasts them against a standard.

Laser Flow Cytometry

A method that uses a laser beam to absorb and scatter light; interruptions in the beam provide a cell count while light scatter indicates size and density.

Impedance Counters

Automated machines that use electrical currents to count cells; since cells are poor conductors, the change in electrical impedance (voltage change) is proportional to cell size.

Left Shift

An increased number of immature white blood cells (WBC) in circulation.

Lipemia

The presence of excess lipids in the blood which can interfere with the analysis of plasma protein, fibrinogen, and hemoglobin.

Ethylenediaminetetraacetic acid (EDTA)

The preferred anticoagulant in purple-top tubes for hematology; its mode of action is forming calcium salts to remove calcium.

Heparin Disadvantages

Compared to EDTA, it can cause leukocytes to stain poorly and may result in platelet clumping.

Bright Red Blood

Color characteristic of a normal arterial sample or hemolysis.

Bluish Red Blood

Color characteristic of a normal venous sample containing deoxyhemoglobin.

Dark Gray-Blue Blood

Blood color associated with low $O_2$ levels or an old sample.

Milky Blood

Color characteristic of a lipemic sample.

Sludgy Blood

Viscosity state indicating agglutination, clotting, or red granules associated with dehydration.

Packed Cell Volume (PCV)

The volume percentage of red blood cells (RBCs) in blood, also known as microhematocrit, hematocrit ($Ht$ or $HCT$), or Erythrocyte Volume Fraction ($EVF$).

Buffy Coat

The layer in a centrifuged hematocrit tube containing white blood cells and platelets; usually $< 1\,mm$ wide and white in color (red-tinged indicates immature RBCs).

Estimated RBC Count Formula

$\text{PCV} / 6$ with units in $10^6\,cells/\mu L$. For dogs, the normal is approximately $6.8 \times 10^6\,cells/\mu L$; for cats, $7.5 \times 10^6\,cells/\mu L$.

Estimated Hemoglobin Concentration Formula

$\text{PCV} / 3$ with units in $g/dL$.

Plasma Proteins

Constituents making up $5-10\%$ of plasma ($6-8\,g/dL$) including Albumins (osmotic pressure), Globulins (immunity), and Fibrinogen (clotting).

Refractometer

An instrument used to read Total Solids (TS) by measuring how solids in solution bend light; lipemia can falsely increase these values.

Hemoglobin (Hgb)

The functional unit of red blood cells consisting of Heme (iron) and Globin (amino acid chains).

Oxyhemoglobin

The form of hemoglobin that binds to oxygen.

Carboxyhemoglobin

A form of hemoglobin that binds irreversibly to carbon monoxide.

Mean Corpuscular Volume (MCV)

A measure of the average size of red blood cells calculated as $(\text{PCV} / \text{RBC conc.}) \times 10$ and measured in femtoliters ($fl$).

Mean Corpuscular Hemoglobin Concentration (MCHC)

The average concentration of hemoglobin in the average RBC calculated as $(\text{Hgb} / \text{PCV}) \times 100$ with units in $g/dL$.

Mean Cell/Corpuscular Hemoglobin (MCH)

The average weight of hemoglobin per average RBC measured in picograms ($pg$).

Red Blood Cell Distribution (RDW)

Electronic measure of the variation in cellular volume of the RBC population (anisocytosis).

Regenerative Anemia

Anemia characterized by the bone marrow's release of immature RBCs (reticulocytes or polychromatophilic RBCs), usually evident within $3-5$ days.

Microcytic Anemia

Classification of anemia with a low MCV, often associated with iron deficiency.

Romanowsky Stains

A group of stains including Diff-Quik, Wright's, and Wright-Giemsa, composed of a fixative ($95\%$ methanol), Eosin (acidic pH), and Methylene blue (alkaline pH).

Eosin

The component of Romanowsky stains with an acidic pH that stains basic components like hemoglobin and eosinophilic granules red.

Methylene Blue

The component of Romanowsky stains with an alkaline pH that stains acidic components like leukocytic nuclei blue.

Anisocytosis

Variation in the size of erythrocytes.

Polychromia

A bluish tint in young erythrocytes caused by organelles in the cytoplasm.

Rouleaux

The arrangement of RBCs in grouped stacks, which is normal in horses and cats but can be an artifact of blood sitting too long.

Agglutination

Clumping of RBCs associated with immune-mediated disorders where antibodies coat the erythrocyte; unlike rouleaux, the clumps do not disperse with saline.

Poikilocytes

Abnormally shaped erythrocytes.

Schistocytes

Red blood cell fragments resulting from intravascular trauma (such as DIC) or iron deficiency.

Drepanocytes

Sickle-shaped red blood cells that are normal in deer and angora goats.

Keratocytes

Erythrocytes known as 'Blister cells' or 'Bite cells' that appear to have vacuoles; associated with hemangiosarcoma or neoplasia.

Spherocytes

Dark-staining RBCs with reduced or no central pallor, suggesting immune-mediated RBC destruction (hemolytic anemia).

Acanthocytes

Also known as 'Spur cells', these are spiculated RBCs with unevenly distributed projections, often associated with altered lipid metabolism.

Echinocytes

Also known as 'Burr cells', these are spiculated RBCs with regular projections, associated with renal disease, lymphosarcoma, or rattlesnake envenomation.

Codocytes

Also known as leptocytes or target cells, these have an increased membrane surface area relative to cell volume.

Howell-Jolly Bodies

Basophilic nuclear remnants in young erythrocytes often seen in response to anemia.

Heinz Bodies

Round structures of denatured hemoglobin caused by oxidative drugs or chemicals; normal in up to $5\%$ of feline RBCs.

Basophilic Stippling

Small, dark-blue bodies of residual RNA in RBCs, common in cows and cats, or lead poisoning in dogs.

Pelger-Huët Anomaly

A congenital defect characterized by nuclear hyposegmentation (condensed, unsegmented nuclear chromatin) in leukocytes.

Döhle’s Bodies

Toxic changes in neutrophils appearing as retained rough ER, indicating bacterial infection or toxemia.

Reactive Lymphocytes

Atypical lymphocytes with azurophilic granules and cleaved nuclei, usually resulting from secondary antigenic stimulation (vaccination or infection).

Mycoplasma haemofelis

Small ($0.2-0.5\,\mu m$) coccoid, rod, or ring-shaped bacteria that affect feline RBCs, causing feline infectious anemia.

Babesia

Teardrop-shaped, often paired hemoprotozoa ($3-4\,\mu m$) found in RBCs; transmitted by ticks.

Ehrlichia canis

A rickettsial organism transmitted by the brown dog tick that affects monocytes and neutrophils, appearing as small clusters called morulae.

Anaplasma marginale

Small, dark-staining cocci found at the margins of ruminant RBCs.

Dirofilaria immitis

The heartworm parasite, where the microscopic prelarval stage (microfilariae) can be seen in a blood smear.