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Day 2 Flashcards

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1
Q

What is the name of the counting chamber used for hematological cell counts?

A

Hemacytometer

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2
Q

Which type of manual cell count is not usually performed due to high error rate?

A

RBC

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3
Q

Manual WBC and platelet counts are usually performed due to a(n) ____________ number of cells

A

Decreased

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4
Q

What is the purpose of diluting fluid in manual cel counts?

A

Destroy cellular element that are not to be counted

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5
Q

What clinical condition will be seen in the following disease states: acute bacterial infections, severe malaria and pregnancy?

A

Leukocytosis

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6
Q

What is the principle for cell counts based on?

A

Osmotic pressure of cells

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7
Q

What are the losing agents used in WBC cell counts?

A

Acetic acid, hydrochloric acid or distilled water

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8
Q

What are the dimensions of the etched grid on the hemacytometer?

A

3 X 3mm

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9
Q

What is the depth of the space between the hemacytometer grid and the coverglass?

A

0.1mm above grid surface

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10
Q

What reagents are included in the diluent of the unopette system and what is the purpose of each?

A

Ammonium oxalate- fixes WBCs & platelets

Phosphate buffer- maintains pH

Thermisol- antibacterial agent

Distilled water- lyses RBCs

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11
Q

What is the volume of the capillary pipette on the unopette system, for WBCs and platelets?

A

20 microliters

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12
Q

How many times is the unopette inverted after adding patient sample?

A

5-10 times

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13
Q

Why is the unopette allowed to stand at room temperature for 10min?

A

To allow RBCs to lyse

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14
Q

How many drops from the unopette should be discarded before adding the solution to the hemacytometer?

A

First 3-4 drops

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15
Q

How should the pipette tip of the unopette be positioned when charging the hemacytometer?

A

45 degrees right under edge of coverglass

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16
Q

Describe how the solution should flow through the hemacytometer.

A

Continuously and evenly; until it fills the chamber

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17
Q

Why do we allow the hemacytometer to sit undisturbed for 10min after charging ?

A

To allow cells to settle in the same focal plane

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18
Q

What is the purpose of the moist gauze in the manual cell count procedure?

A

Prevents evaporation during incubation period

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19
Q

What microscopic power should cell counts be focused/read at?

A

Low power

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20
Q

What area of the hemacytometer is counted for manual WBC cell counts?

A

Outer 4 corners mm(squared) areas on each side

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21
Q

In what position on the hemacytometer grid are cells NOT counted?

A

Cells tounching the bottom or right hand side lines of each square

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22
Q

The two sides of the hemacytometer should agree within what percentage?

A

Plus or minus 20%

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23
Q

What is cell count formula?

A

Come back ***

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24
Q

What is the dilution factor and area for the WBC count formula ?

A

Dilution factor- 100

Area- 4

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25
What does the International Committee for Standardization recognize as the unit of volume for hematology?
Liter
26
What is the normal WBC count for an adult?
4.5-11.0 x 10 to the 9th power WBC / L
27
How soon after diluting must a WBC cell count be accomplished?
3hours
28
List some sources of error for WBC counts.
- Improper mixing of blood - Incorrect whole blood/anticoagulant ratio - Dirt/debris on hemacytometer/coverglass - Improperly adjusted condenser - Allowing hemacytometer to dry out - Calculation errors - Uneven distribution of cells - Not performing w/in 3hours of diluting
29
What clinical condition will be seen in the following bleeding disorders and/or bone marrow abnormalities: pernicious/aplastic anemia, chemotherapy/ radiation treatment, and thrombocytopenic purpura?
Thrombocytopenia
30
What are the requirements of a platelet count diluent?
- Lyses RBCs; preserves platelets - reduce adhesiveness of platelets - must provide a low specific gravity, so platelets settle in one plane
31
List the types of platelet diluent and associated reagent?
Rees- Ecker - sodium citrate | Beecher-Cronkrite - ammonium oxalate
32
Which type of platelet diluent is used in the unopette method ?
Beecher-Cronkite
33
At what magnification are platelets counted in the unopette procedure?
High-dry (40x)
34
What placement should the condenser be when counting platelets in the unopette procedure?
Remain in the full down position
35
What area of the hemacytometer is counted for manual platelet cell counts?
Middle mm(squared) on both sides of hemacytometer
36
Describe the size and appearance of platelets when reading the unopette procedure.
Round, oval or spindle shaped and are 1-3 microliters in diameter
37
What is the dilution factor and area for the platelet count formula?
Dilution factor- 100 | Area- 1
38
What is the units of measure for platelet’s scientific notation?
Liter
39
What is the normal value for platelets
150-400 x 10 to the 9th power Plt/L
40
List some platelet count specific sources of error for the unopette procedure?
Counting dust and debris as platelets Specimen older that one day may exhibit platelet clumping
41
What disorder would be expected if the patient was suspected to have one of the following disease states: blood loss , autoimmune disorder, B12/folate deficiency, infection or an immune disorder?
Anemia
42
What is anemia?
Condition in which RBCs are being destroyed fasted than they are produced or their ability to carry oxygen is hindered
43
What are the purposes of the RBC count ?
- calculates RBC indices - measures response to treatment - detects and ID anemias(sickle cell, hemolytic, pernicious) - detects the presence of RBCs in body fluid
44
What is the diluent used in the unopette for RBC counts?
Physiological saline (0.85%)
45
At what magnification are RBCs counted in the unopette procedure?
High dry 40x
46
What area of the hemacytometer is counted for manual RBC cell counts?
Outside 4 corners and middle squares
47
TRUE OR FALSE A variation of more than 35 RBCs between any of the five squares indicates an invalid count, and the count must be repeated.
False, 25
48
What is the dilution factor and area for the RBC count formula?
Dilution factor- 200 | Area- 0.2mm squared
49
What is the normal RBC value for an adult male?
4.5-6.0 x 10 to the 12 power RBCs/L
50
What is a RBC count specific source of error for the unopette method?
Rouleaux formation
51
What is a retic?
RBC the is mature enough to have lost their nuclei but not their cytoplasmic RNA
52
What is a reticulocyte called if it is NOT stained with supravital stain?
Basophilic/ polychromaphilic erythrocyte
53
A reticent evaluation is a good indication of __________________ activity.
Red bone marrow
54
Describe the effect on the reticulocyte count in the following disease states: hemolytic anemia. Chemotherapy, and pernicious anemia
Increased retic count
55
Name a type of supravital stain used for retic evaluations.
New Methylene Blue
56
Describe the stat of the RBC when it is mixed with the manual NMB stain for retic evaluation.
Living blood
57
What is the blood to stain ratio in the manual NMB procedure?
1:1
58
How long and at what temperature is the stain and sample incubated in the manual NMB procedure?
15 minutes at room temp
59
Describe what an appropriate field will look like when performing the manual NMB procedure
RBCs are evenly distributed but not overlapping
60
At what microscopic power and type should retic cell counts be read at in the manual NMB procedure?
Oil immersion
61
Describe what RBCs and reticulocytes will look like in the manual NMB procedure.
RBCs appear pale green-blue color | Retics appear more blue with strands of blue-purple reticulum
62
How many fields and what approximate number of | RNCs are read in the manual NMB procedure?
4 additional fields(5 in total) | For 1,000 RBCs
63
How are retics calculated in the manual NMB Procedure?
%Retic=Total Retics per 1,000RBC ————————————— 10
64
Describe what the Miller Disk looks like
Contains a small square within a large square (1/9 the size of large square) in the lower left corner
65
How many fields and what approximate number of RBCs are read when counting retics using the Miller Disk Method?
20 fields ( 500-1000 total cells)
66
How are retics calculated in the Miller Disk Method?
Total retics in large square x100 ————————————————— Total RBCs in small square x9 =% retics
67
What is the normal value of retics at birth?
2.5-6.5%
68
What are the sources of error for manual reticulocyte counts?
``` Confusion w/ RBC inclusion Heinz bodies Pappenheimer bodies Refractile area’s Use of heparized while blood will cause retics to stain poorly ```

Hematology (6 decks)

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