Clin Path Lecture 2 (Hematology Instruments and Blood Cell Measurements)

cell count and cell size

What are the 2 things that the impedance method can tell you about cells?

volume

Regarding the impedance method, the change in resistance is proportion to cell _____.

size

Platelet and RBC volume histograms are good for separating by _____ alone, but there is some overlap.

bigger

Cat platelets are much [bigger/smaller] than those of dogs and other domestic species.

smaller

Cat RBCs are [bigger/smaller] than those of dogs.

aggregates

Cat platelets are more reactive than those of other species and therefore clump up to form _____ (plural).

cats

Platelet and RBC volume histograms/impedance instruments are not effective for [cats/dogs].

hemoglobin

Impedance instruments measure _____ spectrophotometrically.

cannot

Impedance instruments [can/cannot] determine the intracellular characteristics of cells.

3

Impedance instruments are only a _____ part differential based on cell size alone (limited accuracy). They have excellent precision, however.

reticulocyte

Impedance instruments are generally less expensive than laser flow instruments but cannot perform _____ counts.

platelet

Impedance instruments give total WBC counts of all species and generally _____ counts (but not cats).

size

Forward scatter tells you what about a cell?

complexity/granularity (internal characteristics)

Side scatter tells you what about a cell?

shadow

The forward scatter detector measures the cell's _____ which is a relative indicator of the cell's size.

lymphocyte

Which cell is smaller? Lymphocyte or neutrophil?

neutrophils

_____ (plural) with their multilobed nucleus and granules have high amounts of side scatter.

lymphocytes

_____ (plural) with their high nucleus:cytoplasm ratio and scant cytoplasm have lower levels of side scatter.

1. internal complexity
2. number
3. size

Laser flow cytometry can determine what 3 characteristics of a cell?

5

Laser flow cytometry gives total WBC and _____ part differential counts, although basophils are not accurately counted in dogs.

can

Laser flow cytometry [can/cannot] count reticulocytes.

basophils

Which type of cells are usually too similar to other types of cells to be counted individually?

True

T/F: The RBC count is of little value by itself.

methemoglobin

Sodium lauryl sulfate (SLS) reagent lyses erythrocytes and oxidizes hemoglobin to what? It forms a stable SLS-MetHb product.

mean cell volume

What does MCV stand for?

mean cell hemoglobin

What does MCH stand for? (not very useful)

mean corpuscular hemoglobin concentration

What does MCHC stand for?

red cell distribution width

What does RDW stand for?

10^15 L

1 femtoliter is how many liters?

erythrocyte size (MCV)

MCH generally correlates directly with changes in what?

iron

The lowest values of MCH are reported in severe _____ deficiency anemia.

True

T/F: MCV (femtoliters, fL) is determined directly in hematology analyzers and not by manual calculation.

anisocytosis

What term describes RBCs that are of different sizes?

RDW

Platelets are sometimes counted in erythrocyte histograms of severely anemic patients which can lead to falsely increased _____.

False

T/F: Absolute reticulocytes counts determined by flow cytometry do not have to be validated using manual counts as the technology is very accurate.

aggregate

Regarding reticulocyte counts in cats, only _____ reticulocytes are counted in most instruments. Therefore, you must verify which reticulocytes are counted in cats.

reticulocytosis

Howell-Jolly bodies, large immature platelets or platelet clumps, and autofluorescence can all cause false _____.

platelets

Using a vacutainer can help provide fewer problems with clumped _____ (plural).

thrombocytopenia

Platelet aggregates can result in false _____.

platelet

_____ activation can occur during blood collection and handling (especially in cats). These structures are particularly reactive in cats.

stained blood film examination

What is one way, according to the lecture, to verify platelet counts, especially thrombocytopenia?

cats

Automated platelet counts are often unreliable in what animals?

mean platelet volume

What does MPV stand for? It is the average volume of a single platelet.

true

T/F: Values of MPV vary considerably by the method used.

MPV

Both storage of blood at 5C and platelet aggregates can cause falsely elevated _____.

leukocytes

Nucleated erythrocytes in blood may be counted as _____ (plural) by manual and most automated cell counters.

nucleated red blood cells per 100 WBCs

What does NRBC stand for?

true

T/F: Clots trap all types of cells. Therefore, clot formation causes all cell types to decrease.

old

Erythrocyte swelling, platelet aggregation, and cell lysis of all cell types can happen with _____ blood samples.

leukocytes or platelets

Cryoglobulins, which precipitate below body temp., may be counted as what other 2 cells?

leukocytes and reticulocytes

Heinz bodies can cause what 2 other cells types to potentially be increased spuriously?