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Hematology > Day 2 > Flashcards

Day 2 Flashcards

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
Q

What does the International Committee for Standardization recognize as the unit of volume for hematology?

A

Liter

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26
Q

What is the normal WBC count for an adult?

A

4.5-11.0 x 10 to the 9th power WBC / L

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27
Q

How soon after diluting must a WBC cell count be accomplished?

A

3hours

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28
Q

List some sources of error for WBC counts.

A
  • 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
Q

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?

A

Thrombocytopenia

30
Q

What are the requirements of a platelet count diluent?

A
  • Lyses RBCs; preserves platelets
  • reduce adhesiveness of platelets
  • must provide a low specific gravity, so platelets settle in one plane
31
Q

List the types of platelet diluent and associated reagent?

A

Rees- Ecker - sodium citrate

Beecher-Cronkrite - ammonium oxalate

32
Q

Which type of platelet diluent is used in the unopette method ?

A

Beecher-Cronkite

33
Q

At what magnification are platelets counted in the unopette procedure?

A

High-dry (40x)

34
Q

What placement should the condenser be when counting platelets in the unopette procedure?

A

Remain in the full down position

35
Q

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

A

Middle mm(squared) on both sides of hemacytometer

36
Q

Describe the size and appearance of platelets when reading the unopette procedure.

A

Round, oval or spindle shaped and are 1-3 microliters in diameter

37
Q

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

A

Dilution factor- 100

Area- 1

38
Q

What is the units of measure for platelet’s scientific notation?

A

Liter

39
Q

What is the normal value for platelets

A

150-400 x 10 to the 9th power Plt/L

40
Q

List some platelet count specific sources of error for the unopette procedure?

A

Counting dust and debris as platelets

Specimen older that one day may exhibit platelet clumping

41
Q

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?

A

Anemia

42
Q

What is anemia?

A

Condition in which RBCs are being destroyed fasted than they are produced or their ability to carry oxygen is hindered

43
Q

What are the purposes of the RBC count ?

A
  • calculates RBC indices
  • measures response to treatment
  • detects and ID anemias(sickle cell, hemolytic, pernicious)
  • detects the presence of RBCs in body fluid
44
Q

What is the diluent used in the unopette for RBC counts?

A

Physiological saline (0.85%)

45
Q

At what magnification are RBCs counted in the unopette procedure?

A

High dry 40x

46
Q

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

A

Outside 4 corners and middle squares

47
Q

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.

A

False, 25

48
Q

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

A

Dilution factor- 200

Area- 0.2mm squared

49
Q

What is the normal RBC value for an adult male?

A

4.5-6.0 x 10 to the 12 power RBCs/L

50
Q

What is a RBC count specific source of error for the unopette method?

A

Rouleaux formation

51
Q

What is a retic?

A

RBC the is mature enough to have lost their nuclei but not their cytoplasmic RNA

52
Q

What is a reticulocyte called if it is NOT stained with supravital stain?

A

Basophilic/ polychromaphilic erythrocyte

53
Q

A reticent evaluation is a good indication of __________________ activity.

A

Red bone marrow

54
Q

Describe the effect on the reticulocyte count in the following disease states: hemolytic anemia. Chemotherapy, and pernicious anemia

A

Increased retic count

55
Q

Name a type of supravital stain used for retic evaluations.

A

New Methylene Blue

56
Q

Describe the stat of the RBC when it is mixed with the manual NMB stain for retic evaluation.

A

Living blood

57
Q

What is the blood to stain ratio in the manual NMB procedure?

A

1:1

58
Q

How long and at what temperature is the stain and sample incubated in the manual NMB procedure?

A

15 minutes at room temp

59
Q

Describe what an appropriate field will look like when performing the manual NMB procedure

A

RBCs are evenly distributed but not overlapping

60
Q

At what microscopic power and type should retic cell counts be read at in the manual NMB procedure?

A

Oil immersion

61
Q

Describe what RBCs and reticulocytes will look like in the manual NMB procedure.

A

RBCs appear pale green-blue color

Retics appear more blue with strands of blue-purple reticulum

62
Q

How many fields and what approximate number of

RNCs are read in the manual NMB procedure?

A

4 additional fields(5 in total)

For 1,000 RBCs

63
Q

How are retics calculated in the manual NMB Procedure?

A

%Retic=Total Retics per 1,000RBC
—————————————
10

64
Q

Describe what the Miller Disk looks like

A

Contains a small square within a large square (1/9 the size of large square) in the lower left corner

65
Q

How many fields and what approximate number of RBCs are read when counting retics using the Miller Disk Method?

A

20 fields ( 500-1000 total cells)

66
Q

How are retics calculated in the Miller Disk Method?

A

Total retics in large square x100
—————————————————
Total RBCs in small square x9
=% retics

67
Q

What is the normal value of retics at birth?

A

2.5-6.5%

68
Q

What are the sources of error for manual reticulocyte counts?

A 
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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