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HEMATOLOGY 1 > WBC COUNT > Flashcards

WBC COUNT Flashcards

1
Q

Improved Neubauer Counting Chamber features

A

Two identical sides, each counted, 3 mm by 3 mm, divided into 9 square millimeters

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2
Q

Purpose of the 4 corner (large) squares

A

Used for manual WBC count

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3
Q

Purpose of the middle (central) square

A

Used for manual RBC count

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4
Q

Coverglass for the counting chamber

A

Thick coverglass is used, not ordinary coverglasses, as they have uneven surfaces

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5
Q

Space between the coverglass and platform

A

0.1 mm thick, forming a space holding exactly 0.1 cu.mm

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6
Q

RBC Thoma pipet markings

A

0.5, 1, 101

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7
Q

Color of RBC Thoma pipet bead

A

Red

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8
Q

Volume of RBC Thoma pipet

A

100

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9
Q

WBC Thoma pipet markings

A

0.5, 1, 11

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10
Q

Color of WBC Thoma pipet bead

A

White, colorless

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11
Q

Volume bulb of WBC Thoma pipet

A

10

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12
Q

Purpose of diluting fluids

A

Disperse blood cells to facilitate counting

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13
Q

Diluting fluids for WBCs

A

1% ammonium oxalate, 3% acetic acid, 1% hydrochloric acid

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14
Q

Common dilution for WBCs

A

1:20 and 1:100

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15
Q

Objectives and area counted for WBCs (1:20 dilution)

A

4 mm², 10x

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16
Q

Objectives and area counted for WBCs (1:100 dilution)

A

9 mm², 10x

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17
Q

Effect of 1% hydrochloric acid on NRBCs

A

NRBCs are not lysed, so they may be counted with WBCs and cause falsely increased WBC count.

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18
Q

Platelet diluting fluid

A

1% ammonium oxalate

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19
Q

Platelet dilution

A

1:100

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20
Q

Objective for counting platelets

A

40x (phase)

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21
Q

Area counted for platelets

A

1 mm²

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22
Q

RBC diluting fluid

A

Isotonic saline

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23
Q

RBC dilution

A

1:100

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24
Q

Objective for counting RBCs

A

40x

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25
Q

Area counted for RBCs

A

0.2 mm² (5 small squares of central square)

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26
Q

Manual RBC count

A

Rarely performed due to technical/clerical error

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27
Q

Specimen used for WBC count

A

EDTA whole blood or blood from a skin puncture

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28
Q

Typical dilution for WBC count

A

0.05555555555555558

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29
Q

Function of diluting fluid in WBC count

A

Lyses non-nucleated RBCs to prevent interference

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30
Q

Larger area counting in WBC count

A

Performed when WBC count is below normal

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31
Q

How to ensure WBC count accuracy

A

Perform WBC estimate using Wright-stained PBS

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32
Q

Cleaning method for hemocytometer and coverslip

A

Clean with alcohol and dry with lint-free tissue

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33
Q

Timeframe for performing WBC count after dilution

A

Within 3 hours

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34
Q

Purpose of moist chamber in WBC count

A

Allows cells to settle for 10 minutes before counting

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35
Q

Microscope focus for WBC count

A

Use low-power (10x) objective, ensure even cell distribution

36
Q

Cells to count in 1:20 dilution

A

All cells in 4 corner squares, starting with upper left square

37
Q

Cells touching top and left lines

A

Counted (TLC)

38
Q

Cells touching bottom and right lines

A

Ignored (BRI)

39
Q

Repeat counting on opposite side of chamber

40
Q

Acceptable percentage difference between sides

41
Q

Formula for percentage difference

A

((V1 - V2) / ((V1 + V2) / 2)) x 100

42
Q

V1 and V2 in percentage difference formula

A

V1 = larger volume, V2 = smaller volume

43
Q

How to calculate WBC count

A

Average cells counted on both sides, then use formula: (cells counted x dilution factor) / (area x depth)

44
Q

Formula for WBC count calculation

A

No. of cells/µL = (cells counted x dilution factor) / (area (mm2) x depth (0.1))

45
Q

Correction of WBC count

A

Performed if > 5 NRBCs seen in 100 WBCs

46
Q

Formula for WBC count correction

A

uncorrected WBC x (100 / (100 + NRBCs))

47
Q

Rounding for WBC correction

A

Result rounded to the nearest hundreds

48
Q

100-cell differential count

A

Routinely performed

49
Q

200-cell differential count

A

Performed when WBC count > 40 x 10^9/L, or for specific conditions (e.g., > 10% eosinophils)

50
Q

Conditions for 200-cell differential

A

> 10% eosinophils, > 2% basophils, > 11% monocytes, more lymphocytes than neutrophils

51
Q

Division for 200-cell differential results

A

Results divided by 2

52
Q

Indication for 200-cell differential

A

Indicate in report that 200 WBCs were counted

53
Q

300 or 400-cell differential count

A

Performed when WBC count > 100 x 10^9/L to increase accuracy

54
Q

50-cell differential count

A

Performed when WBC count < 1.0 x 10^9/L, using buffy coat smear

55
Q

How to perform 50-cell differential

A

Count 50 WBCs, then multiply by 2 to get percentage

56
Q

Relative count

A

Number of specific WBC types per 100 WBCs, less informative than absolute count

57
Q

Relative count reference ranges

A

Neutrophil: 51% to 67%, Lymphocyte: 25% to 33%, Monocyte: 2% to 6%, Eosinophil: 1% to 4%, Basophil: 0% to 1%

58
Q

Absolute count

A

Number of specific WBC types per cubic millimeter (mm3) of blood, more informative than relative count

59
Q

Formula for absolute count

A

Relative count (%) x WBC count = Absolute count (per mm3)

60
Q

Absolute count reference ranges

A

Neutrophil: 1,600/µL to 7,260/µL, Lymphocyte: 960/µL to 4,400/µL, Monocyte: 180/µL to 880/µL, Eosinophil: 45/µL to 440/µL, Basophil: 45/µL to 110/µL

61
Q

Shift to the Left

A

Increase in young forms of WBCs, 2 types: Degenerative and Regenerative

62
Q

Degenerative Shift to the Left

A

Increase in young forms, seen in tuberculosis, normal/decreased WBC count

63
Q

Regenerative Shift to the Left

A

Increase in young forms, seen in appendicitis, WBC count elevated

64
Q

Shift to the Right

A

Increase in old forms of neutrophils, seen in pernicious anemia

65
Q

Leukoerythroblastic Reaction synonyms

A

Leukoerythroblastosis, Leukoerythroblastic anemia

66
Q

Leukoerythroblastic Reaction key features

A

Immature neutrophils, nucleated RBCs, teardrop RBCs

67
Q

Leukoerythroblastic Reaction accompanied by neutrophilia

A

Often, but not always

68
Q

Leukoerythroblastic Reaction significance

A

Nonspecific, indicates underlying disease or stress to hematopoietic compartment

69
Q

Leukoerythroblastic Reaction association with PMF

A

Strongly associated with primary myelofibrosis

70
Q

Leukoerythroblastic Reaction in myelophthisis

A

Seen in metastatic tumor, fibrosis, lymphoma, leukemia

71
Q

Leukoerythroblastic Reaction in mild cases

A

Observed in hemolytic anemia, severe infections, cardiac failure, uremia, megaloblastic anemia

72
Q

Smudge cells appearance

A

Nuclear remnants of lymphocytes, thumbprint shape, structureless chromatin

73
Q

Smudge cells normal occurrence

A

Found in few numbers, may be associated with chronic lymphocytic leukemia (CLL)

74
Q

Basket cells appearance

A

Nuclear remnants of granulocytic cells, netlike chromatin pattern

75
Q

Basket cells normal occurrence

A

Found in few numbers, may be seen in some leukemias

76
Q

Necrotic cells description

A

Granulocytic cells with pyknotic nuclei, agranular cytoplasm

77
Q

Necrotic cells cause

A

Prolonged exposure to EDTA, rarely chemotherapy

78
Q

Phagocytic cells description

A

Neutrophils engulfing foreign bodies like bacteria and fungi

79
Q

Phagocytic cells association

A

Overwhelming septicemia, bacterial and fungal infections, erythrophagocytosis

80
Q

Endothelial cells description

A

Large cells (20 to 30 um), stretched and ovoid appearance, single nucleus with dense chromatin

81
Q

Endothelial cells appearance

A

Abundant translucent cytoplasm, no nucleoli, usually found at feather edge

82
Q

Endothelial cells occurrence

A

Contaminant of venipuncture, occasionally found in blood obtained by venipuncture

83
Q

Endothelial cells distinction

A

Must not be confused with clumps of malignant cells

84
Q

Megakaryocyte fragments description

A

Nude nuclei, dark purple staining

85
Q

Megakaryocyte fragments occurrence

A

Found in newborns, aberrant platelet production, myelofibrosis, essential thrombocythemia

86
Q

Nucleated red blood cells (NRBCs) description

A

Varies with cell maturity

87
Q

Nucleated red blood cells (NRBCs) occurrence

A

Found in newborns, hemolysis, leukemia, myeloproliferative disorders

HEMATOLOGY 1 (29 decks)

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