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Hematology basics pt 1 jpg

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Hematology basics pt 1 jpg

  1. 1. THE BLOODY TRUTH ABOUT CATS AND DOGS HEMATOLOGY BASICS: DIFFERENTIALS Sarah Ouellette, CVT
  2. 2. Why we run a CBC • Provides broad overview of overall health status • Used for: • General health • Sick patients • Pre-anesthetic • Recheck abnormalities
  3. 3. Hematology Basics • Collection/handling SAMPLE QUALITY IS A MAJOR CONTRIBUTOR TO ANALYTICAL ERRORS • Poor collection/handling methods can lead to: • Inadequate cell counts • Morphologic artifacts
  4. 4. Hematology Basics • EDTA • anticoagulant of choice • LTT • Correct ratio • Low blood volume can cause • False increase in plasma protein • False decrease in PCV/RBC count • Morphologic artifacts
  5. 5. Things to remember! • Make blood smears soon after collection to reduce the risk of artifacts • Especially when sending out for pathology review • Make a good quality smear • unfixed
  6. 6. Why we do a differential • CBC analyzers do NOT give us any information about specific morphological changes or specific cell types • CBC analyzers only “suspect” abnormalities such as nRBC/band cells, etc.
  7. 7. Blood Smear • How to make a good blood smear
  8. 8. Blood smear • Staining: • Wright’s stain • New methylene blue • IVG protocol: • 10 dips in each stain or 30 seconds/stain
  9. 9. Blood Smear Staining • Why its important? Overstaining • Not reliable for accurate results
  10. 10. Reading a blood smear • NEVER NEVER NEVER go looking for something abnormal – unless indicated • Examples: • Automated analyzer suspects an abnormality: • Nucleated RBC • Band cells • Abnormal (high/low) cell count
  11. 11. RED BLOOD CELLS: ERYTHROCYTES
  12. 12. Erythrocytes • Non-nucleated cells • Biconcave disk • Prominent central pallor • Stain pink/salmon color • Function: transport oxygen between lungs and tissues • Hemoglobin is the O2 carrying component of the cell
  13. 13. Erythrocytes • Canine: • Lifespan = 110-120 days • Slightly larger than cats • Mild polychromasia • Abnormalities that can be seen in healthy dogs: • Occasional nucleated RBC • Occasional howell jolly bodies
  14. 14. Erythrocytes • Feline: • Lifespan: 65-76 days • Smaller than canine RBC’s • More variable in size • Little to no central pallor • Abnormalities that can be seen in healthy cats: • Occasional heinz bodies • Small # of howell jolly bodies
  15. 15. Abnormal Hemogram • Polychromasia • Color variance with RBC • Indicative of immature RBC within the blood • MILD variance is accepted in cats and dogs • Causes: • Anemia • Bone marrow disease **importance of staining**
  16. 16. Abnormal Hemogram • Hypochromasia: • Increased central pallor • Cells stain less overall • Low hemoglobin content • Causes: • Iron insufficiency • Chronic blood loss • Anemia
  17. 17. Abnormal Hemogram • Poikilocytes or poikilocytosis: • General term used to describe RBC’s with an abnormal shape • Some abnormalities have specific significance relating to a particular disease while others may be non-specific
  18. 18. Poikilocytes • Acanthocytes (spur cells) • 2-10 blunt/club shaped projections • Different lengths • Irregular intervals • Causes: • Dogs with hemangiosarcoma • Increased blood cholesterol, iron deficiency anemia, renal disease, and occasionally some liver diseases
  19. 19. Poikilocytes • Echinocytes (spiculated or crenated cells) • Numerous sharp/blunt projections • Same length • Evenly spaced around the cell • Causes: • Incidental • excessive EDTA:Blood ratio causes dehydration of cells • Drugs • salicylates, phenylbotazone, Lasix, and certain chemotherapeutic agents
  20. 20. Ecchinocytes • Shown at right are two smears from the same sample, the upper one made while the blood was fresh • The lower made after overnight storage of blood at refrigerator temperature
  21. 21. Poikilocytes • Eccentrocytes • Ragged fringe of cytoplasm along one side of cell • Dense staining • May rupture (hemi-ghosts or “pseudo-spherocytes”) • Causes: • Oxidative damage to cell • Ex. onion toxicity
  22. 22. Poikilocytes • Keratocytes (helmet cells) • Blister-like defect along the perimeter • May rupture (bite-shaped) • Causes: • DIC • Vasculitis • Hemangiosarcoma • Iron deficiency anemia • Hepatic lipidosis in cats
  23. 23. Poikilocytes • Ovalocytes/elliptocytes • Oval/elliptical shape • Causes: • Non-clinical • slide preparation • Clinically in cats with • Hepatic lipidosis • Portosystemic shunt
  24. 24. Poikilocytes • Schistocytes • Cell fragments • Irregular shape (triangular) • Indicates mechanical injury • Causes: • Dogs: DIC, glomerular disease, certain inflammatory diseases, iron deficiency anemia, splenic disease, vasculitis, vascular cancer such as hemangiosarcoma
  25. 25. Schistocytes
  26. 26. Poikilocytes • Stomatocytes • Elongated mouth-like area of central pallor • Due to the absence of hemoglobin • Causes: • Regenerative anemias • Liver disease • Lead poisoning • Non-clinical: blood smear that is too thick
  27. 27. Poikilocytes • Sphereocyte • Smaller, more dense cell • Lack central pallor • Causes: • Immune-mediated hemolytic anemia, fragmentation anemia, oxidative injuries, coral snake envenomation, pyruvate kinase deficiency
  28. 28. Spherocytes • Canine IMHA • Nearly all the cells in this field are spherocytes
  29. 29. Poikilocytes • Codocytes (target cells) • Cluster of hemoglobinized cytoplasm within the area of normal central pallor • Only observed in dogs • Causes: • Cholesterol/phospholipid abnormalities • Regenerative anemia • Liver disease • Non-clinical - Excessive amounts of EDTA
  30. 30. Target cells • Upper panel: numerous target cells in the blood of a dog with cholestasis. • Lower panel: target cells in a dog with regenerative anemia
  31. 31. RBC Inclusions • Red blood cell inclusions can arise from a variety of sources but is important in providing insights into metabolic, physiologic and pathogenic conditions • Inclusion = nuclear or cytoplasmic aggregates (proteins) present within the cell
  32. 32. RBC inclusions • Howell-jolly bodies • Small round basophilic inclusion • Deeply staining non-functioning nuclear remnant • Rare in normal dogs • Cats may have low #’s • Removed by the spleen • Causes: • Regenerative anemias • Splenic disease
  33. 33. Howell-jolly bodies • Howell-Jolly bodies in the blood of a (non-anemic) splenectomized dog
  34. 34. RBC Inclusions • Distemper • Aggregates of viral particles • Found in RBC,WBC, epithelial cells • Rarely seen even with positive infection • Larger than Howell-jolly bodies
  35. 35. Abnormal Hemogram • Basophilic stippling • Spontaneous aggregation of ribosomal RNA in the cytoplasm of young erythrocytes • Causes: • Regenerative anemia • Bone marrow disorders • Lead poisoning (absence of anemia)
  36. 36. RBC inclusions • Heinz Bodies • Small pink/clear short blunt projection • Precipitates of denatured or oxidized hemoglobin • Uncommon in dog/ common in cats • Confirm w/ New methylene blue stain • Causes • Onion toxicity (dogs) • Endogenous HB in cats • (diabetes, lymphoma, hyperthyroidism)
  37. 37. Heinz bodies • Blood from a cat with Heinz body hemolytic anemia associated with acetaminophen toxicity. Upper panel: the large Heinz bodies are causing severe distortion of the cell outline. Lower panel: stained with New Methylene Blue.
  38. 38. Abnormal Hemogram • Metarubricytes (nucleated RBC) • Late stage nucleated red blood cells • Chromatin is markedly clumped and the cytoplasm is more abundant than that of a lymphocyte • Causes: • Regenerative anemias • Acute lead toxicity • Bone marrow disease • Septicemia
  39. 39. Metarubricytes/Nucleated RBC • Left panel: metarubricyte from a dog. • Middle panel: basophilic rubricyte from a dog. • Right panel: a megaloblastoid nRBC from a cat with myelodysplastic syndrome.
  40. 40. Abnormal hemogram • Rouleaux formation • Arranged in overlapping chains • Stacks of coins • Common in cats • Weak clumping (proteins) • Usually not significant
  41. 41. Abnormal hemogram • Agglutination • Irregular disorganized clumps • Irreversible • Pathologically significant • Immune mediated disease • Saline agglutination test to confirm
  42. 42. Abnormal hemogram • Reticulocytes • Young non-nucleated cells • Retained ribosomal DNA • Appear as small dark blue dots within the cell • Polychromatophils stained with New Methylene blue stain • Causes: • Anemia • Bone marrow disease
  43. 43. Reticulocytes • Upper panel: Polychromatophilic RBCs in regenerative anemia in a cat. • Lower panel: reticulocytes stained with NMB from the same cat
  44. 44. RBC Parasites • There are several organisms that can be detected from examination of a peripheral blood smear. • Some organisms can cause significant disease in the host while others can be non-pathogenic.
  45. 45. RBC parasites • Babesia canis • Protozoal parasite transmitted via brown dog tick • Hemolytic anemia seen in in mild dz • Intravascular hemolysis seen in severe dz • B. canis appear usually as a single or multiple pear shaped organisms within the cell • Babesia in endemic in greyhounds.
  46. 46. RBC parasites • Mycoplasma haemofelis • Formally known as hemobartonella • Transmitted through infected fleas • Epicellular bacterial parasite • Observed as small blue cocci, rings, or rods on the edges or the surface of the red cells • Can be mistaken for stain participate • Causes hemolytic anemia
  47. 47. RBC parasites • Mycoplasma haemocanis • Formally known as hemobartonella • Transmitted through infected fleas • Epicellular bacterial parasite • Recognized as chains of cocci across the face of the red cell • Can be mistaken for stain participate • Rarely causes anemia in dogs
  48. 48. Artifacts • Artifacts can significantly impair the examination of a blood smear However, They can be easily avoided • The most common cause of these artifacts is error in handling, collection, storage and preparation of the blood smear
  49. 49. Artifacts • Stain participate • Can be mistaken for Inclusions or parasites • Caused by: • Old stains • Bacterial growth
  50. 50. Artifacts • Water • Caused by precipitation in fixative • Moth eaten appearance • Refractile • As you focus up and down on the microscope the artifact “flashes” ** Always want to make sure stains covers are on tight**
  51. 51. ???
  52. 52. Questions?

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