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Flashcards

Clin Lab Laboratory Notes

Shauna Ryner Veterinary Medicine Inglês 47 flashcards

Flashcards do conjunto (47)

  1. 1Blood Smear ExaminationImportant part of CBC. Allows count of different types of WBC's, platelet estimate, visualize morphological abnormalities/variations in blood cells. Perform as a quality check of automated cell counts. Scan at 10x, checking feathered edge. Then 40x, and finally oil immersion
  2. 2Blood Smear PreparationAlways prepare more than 1 blood smear. Try to make it a thumb print shape, with a good monolayer.
  3. 3Feathered Edge (Blood Smear)Too thin for ID of WBCs and morphological assessment, but should be scanned at low power to detect platelet clumps and parasites (microfiliria). RBCs appear more flattened and may lack central pallor and abnormal shapes are difficult to recognize
  4. 4Too thick (Blood Smear)Too thick for ID and assessment of blood cells. Dries too slowly for WBCs to spead out and they may appear shrunken and smaller than they normally should. Same applies for RBCs in that they may appear stacked due to slow drying.
  5. 5Monolayer (Blood Smear)Examine under oil immersion, just in front of the feathered edge. Cells evenly and randomly distributed and not distorted. Differential counts and morphological characteristics assessed here.
  6. 6Labelling SlidesWrite in pencil. Include case number/animal name, client name, and date of collection
  7. 7Diff-QuikStains for hematology and cytology. Keep lids capped when not in use to prevent evaporation and contamination. Don't top off solutions - empty then clean and dry and refill with fresh solutions. Strain/filter solutions occasionally to remove debris that may accumulate during use.
  8. 8What stains have the same basic principles of nuclear material staining purple and eosinophilic granules staining pink/red?Diff-quik, Dip-quik, wright's stain, and romanowsky-type stain
  9. 9Common Artifacts of preparation that affect blood smearsCrenation, water artifact, stain precipitation, and smudged cells
  10. 10CrenationStar shaped. Most commonly caused by slow drying of the smear and aging of blood in collection tube- can generally see crenated RBC's in the thick part of any blood smear
  11. 11Water ArtifactMay appear as refractile 'bubbles' on surface of RBCs - results from exposure of the smear to water (high humidity, contamination of the fixative with water)
  12. 12Stain PrecipitateOften seen as microscopic field 'sprinkled' with dark purple granules and may indicate that stains are old, contaminated, needing to be filtered/replaced
  13. 13Smudged CellsOften appear as partly or completely disrupted cells, aging of blood in tube can result in smudged cells
  14. 14When Should analysis of blood take place after collection?As soon as possible, and ideally within 30 minutes. If you can't examine during this time period, air-dried, unfixed smears usually hold up well
  15. 15Preparation of Blood Smears (6 steps)1) Slides clean, dry, free of lint
    2) Small drop of blood placed approx. 1cm from end of frosted end of slide
    3) Position slide horizontally with drop of blood nearest to hand doing spreading
    4) Bring spreader just to touch the blood, and allow it to spread evenly on back of spreader
    5) Move spreader to other end of slide using only weight of spreader
    6) Waved/air dried and labelled
  16. 16Characteristics of a good blood smear (5)1) Smooth, even surface free of ridges, waves or holes
    2) Occupy middle 1/2 to 1/3 of slide, with margins on side and edge
    3) Not too thin, and has smooth tail
    4) Not too thick, or cells crowded and dificult to ID
    5) Smooth spreader essential to avoid excess aggregation of cells along edges and tail and eliminate distortion
  17. 17Causes of Poor Blood Smears-Dirty, greasy, wet slides
    -Jagged-edged spreader or too-wide spreader
    -too much or too little blood
    -too slow spreading or too slow drying with RBC crenation
    -spreader pushed with jerky or curved manner, lifted while spreading, or irregularly applied pressure
  18. 18Dog Blood Collection sites and Common needle gaugesJugular
    Cephalic
    Saphenous
    18-20g
  19. 19Cat Blood Collection SItes and Appropriate needle gaugeJugular
    Femoral
    Cephalic
    22g
  20. 20Horse blood collection sites and appropriate needle gaugesJugular
    18 or 16g
  21. 21Cow Blood Collection Sites and Appropriate needle gaugesJugular
    Coccygeal
    16 or 14g
  22. 22What type of anticoagulant is in a green top tube and what will it provide?Heparin is the anticoagulant.
    Provides plasma and whole blood
  23. 23What type of anticoagulant is in a red top tube and what will it provide?No anticoagulant. Provides serum.
  24. 24What type of anticoagulant is in a purple top tube and what will it provide?The anticoagulant is EDTA. It provides plasma and whole blood. Preferred for blood smears as EDTA preserves cell morphology better
  25. 25What type of anticoagulant is in a Serum-Separator Tube (SST) and what will it provide?No anticoagulant, instead there is a gel separator. Provides serum.
  26. 26How do you store serum if you need to keep it for a prolonged period of time?In the fridge, or in the freezer (6+ months). Physically remove from cells or clot. For serum or plasma, you always store them separately
  27. 27Why do you always make more than one blood smear per blood sample?Confirm what you are seeing, or if there is an error/issue with one slide you have another to examine. If you make a few extra then you also have unstained slides that you can send out if needed.
  28. 28What must you think of when collecting blood?Collection time: too slow may lead to clotting, so use an appropriate gauge needle and location.
    Place in proper tube, label tube, and collect the appropriate amount of blood for the tube you are using
  29. 29How can we maintain our stains in their best condition?Always close containers when not in use (prevent contamination and evaporation), filter regularly, don't top up if too low, use stain for hematology only (think clean vs. dirty stain containers)
  30. 30Identifying PlateletsVery small (approx. 3 microns wide) difficult to visualize shape but discoid and contains no nucleus. When stained with Wright's stain, the platelet appears light purple and may contain small purplish granules with fine thread-like projections occasionally able to be visualized.
  31. 31Identifying Red Blood CellsAnucleate biconcave discs that stain red to reddish orange with Wright's stain. Described by size, shape, and degree of central pallor (lighter staining area). Cat RBCs ~5 microns and have less central pallor than dogs. Dogs RBCs ~7 microns with prominent central pallor.
  32. 32NeutrophilsMost common leukocyte in peripheral blood of dogs/cats. Segmented neutrophils ~10-12 microns in diameter. Nucleus usu has several indentations that divide it into lobes (3-5). Wright's stain makes nucleus stain dark purple with dense chromatin and cytoplasm stains pink/purple with small dark granules
  33. 33Band NeutrophilsRare in normal circulation. Nucleus is horshoe in shape and the ends are often round and larger than the middle portion of the nucleus
  34. 34EosinophilsGenerally present in low numbers in normal animals. Similar in size and nuclear appearance to neutrophils. Wrights stain: cytoplasmic granules stain reddish-pink (species variations)
  35. 35BasophilsSeldom seen in peripheral blood. Nucleus may be segmented but not to extent of neutrophil segmentation. Cytoplasm light purple in colour and few, round bluish/purple granules may be seen in cytoplasm (canine) but more difficult to see discrete granules in felines
  36. 36LymphocytesSmaller than neutrophils but larger than RBCs (~7-9 microns). Nucleus is round or slightly indented with heavy, course clumps of chromatin. Cytoplasm minimal and sometimes can't be seen well (bluish cytoplasm). Reactive lymphocytes seen in some situations
  37. 37MonocytesLarge cells (b/w 15-20 microns in diameter). Variable in appearance, cytoplasm blue-gray and may contain vacuoles. Nucleus variable in shape and may range from oval to irregular or kidney-bean with much more diffuse chromatin
  38. 38Platelet Count EstimateEstimated by counting platelets in at least 10 consecutive oil immersion fields in monolayer. Average counts from the fields and this is the estimate. 8-10 platelets per oil-immersion field common. Always scan feathered edge for platelet clumping. Absolute platelet count obtained using hemocytometer
  39. 39HemocytometerCounting chambers used to determine the number of cells per microliter of blood. Contain two separate grids called neubauer rulings.
  40. 40Differential White Blood Cell CountDetermination of the proportion of each individual type of WBC in a particular blood sample. Performed in monolayer of blood smear. Count a total of at least 100 WBCs and record number of each type seen. Express as relative number
  41. 41Total White Blood Cell CountFill a leuko-tic system. Make sure hemocytometer and coverslip clean and dry. Charge hemocytometer (fill it). Examine under 10x objective. Systematically count cells in large 4 outer corner squares (and all 16 squares within 4 corner squares). Average 2 counts of both grids. Multiply avg by 50, and get WBCs inx10^6/L. Convert to SI units: x10^9/L
  42. 42What reticulocyte percentage indicates a responsive anemia in dogs and cats?>1%. The higher the percentage, the stronger the regenerative response.
  43. 43Reticulocyte CountsPerformed on specially stained blood smears. Important assessment of bone marrow's response to anemia (regenerative vs. non-regenerative). This is a relative count (%)
  44. 44Method for Performing Relative Reticulocyte CountFreshly collected, anti-coagulated blood sample, equal volumes of new methylene blue stain and sample blood mixed in small test tube and allowed to stand for 10 minutes. Mix and prepare more than 1 smear. Count 1000 RBCs including reticulocytes (and keep track of # of reticulocytes).
  45. 45Hematocrit/Packed Cell Volume (PCV)Provides quickest and most accurate measure of RBC component of blood. Fill microcapillary/hematocrit tube with fresh anticoagulated blood. Tubes sealed and centrifuged (high speed 5 mins) and results compared to scale. Subjective exam of colour and clarity of plasma can also be determined
  46. 46Plasma Protein DeterminationAutomated methods (biochem profile) or manually with refractometer. Break microcapillary tube just above the buffy coat/plasma interface. Apply plasma to refractometer and read off scale. Protein value expressed as g/dL. Normal values 6-8g/dL for adults.
  47. 47ReticulocytesImmature RBCs that contain organelles (ribosomes) that are lost as the RBC matures. Cats have two forms: aggregate and punctate. Only count the aggregate form because punctate form does not increase in number in response to anemia. Horses don't normally release reticulocytes

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Veterinary Medicine FlashCards sobre Clin Lab Laboratory Notes, criado por Shauna Ryner em 16-12-2017.
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Shauna Ryner
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