WBC COUNT Flashcards
(87 cards)
1
Q
Improved Neubauer Counting Chamber features
A
Two identical sides, each counted, 3 mm by 3 mm, divided into 9 square millimeters
2
Q
Purpose of the 4 corner (large) squares
A
Used for manual WBC count
3
Q
Purpose of the middle (central) square
A
Used for manual RBC count
4
Q
Coverglass for the counting chamber
A
Thick coverglass is used, not ordinary coverglasses, as they have uneven surfaces
5
Q
Space between the coverglass and platform
A
0.1 mm thick, forming a space holding exactly 0.1 cu.mm
6
Q
RBC Thoma pipet markings
A
0.5, 1, 101
7
Q
Color of RBC Thoma pipet bead
A
Red
8
Q
Volume of RBC Thoma pipet
A
100
9
Q
WBC Thoma pipet markings
A
0.5, 1, 11
10
Q
Color of WBC Thoma pipet bead
A
White, colorless
11
Q
Volume bulb of WBC Thoma pipet
A
10
12
Q
Purpose of diluting fluids
A
Disperse blood cells to facilitate counting
13
Q
Diluting fluids for WBCs
A
1% ammonium oxalate, 3% acetic acid, 1% hydrochloric acid
14
Q
Common dilution for WBCs
A
1:20 and 1:100
15
Q
Objectives and area counted for WBCs (1:20 dilution)
A
4 mm², 10x
16
Q
Objectives and area counted for WBCs (1:100 dilution)
A
9 mm², 10x
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.
18
Q
Platelet diluting fluid
A
1% ammonium oxalate
19
Q
Platelet dilution
A
1:100
20
Q
Objective for counting platelets
A
40x (phase)
21
Q
Area counted for platelets
A
1 mm²
22
Q
RBC diluting fluid
A
Isotonic saline
23
Q
RBC dilution
A
1:100
24
Q
Objective for counting RBCs
A
40x
25
Area counted for RBCs
0.2 mm² (5 small squares of central square)
26
Manual RBC count
Rarely performed due to technical/clerical error
27
Specimen used for WBC count
EDTA whole blood or blood from a skin puncture
28
Typical dilution for WBC count
0.05555555555555558
29
Function of diluting fluid in WBC count
Lyses non-nucleated RBCs to prevent interference
30
Larger area counting in WBC count
Performed when WBC count is below normal
31
How to ensure WBC count accuracy
Perform WBC estimate using Wright-stained PBS
32
Cleaning method for hemocytometer and coverslip
Clean with alcohol and dry with lint-free tissue
33
Timeframe for performing WBC count after dilution
Within 3 hours
34
Purpose of moist chamber in WBC count
Allows cells to settle for 10 minutes before counting
35
Microscope focus for WBC count
Use low-power (10x) objective, ensure even cell distribution
36
Cells to count in 1:20 dilution
All cells in 4 corner squares, starting with upper left square
37
Cells touching top and left lines
Counted (TLC)
38
Cells touching bottom and right lines
Ignored (BRI)
39
Repeat counting on opposite side of chamber
Yes
40
Acceptable percentage difference between sides
< 10%
41
Formula for percentage difference
((V1 - V2) / ((V1 + V2) / 2)) x 100
42
V1 and V2 in percentage difference formula
V1 = larger volume, V2 = smaller volume
43
How to calculate WBC count
Average cells counted on both sides, then use formula: (cells counted x dilution factor) / (area x depth)
44
Formula for WBC count calculation
No. of cells/µL = (cells counted x dilution factor) / (area (mm2) x depth (0.1))
45
Correction of WBC count
Performed if > 5 NRBCs seen in 100 WBCs
46
Formula for WBC count correction
uncorrected WBC x (100 / (100 + NRBCs))
47
Rounding for WBC correction
Result rounded to the nearest hundreds
48
100-cell differential count
Routinely performed
49
200-cell differential count
Performed when WBC count > 40 x 10^9/L, or for specific conditions (e.g., > 10% eosinophils)
50
Conditions for 200-cell differential
> 10% eosinophils, > 2% basophils, > 11% monocytes, more lymphocytes than neutrophils
51
Division for 200-cell differential results
Results divided by 2
52
Indication for 200-cell differential
Indicate in report that 200 WBCs were counted
53
300 or 400-cell differential count
Performed when WBC count > 100 x 10^9/L to increase accuracy
54
50-cell differential count
Performed when WBC count < 1.0 x 10^9/L, using buffy coat smear
55
How to perform 50-cell differential
Count 50 WBCs, then multiply by 2 to get percentage
56
Relative count
Number of specific WBC types per 100 WBCs, less informative than absolute count
57
Relative count reference ranges
Neutrophil: 51% to 67%, Lymphocyte: 25% to 33%, Monocyte: 2% to 6%, Eosinophil: 1% to 4%, Basophil: 0% to 1%
58
Absolute count
Number of specific WBC types per cubic millimeter (mm3) of blood, more informative than relative count
59
Formula for absolute count
Relative count (%) x WBC count = Absolute count (per mm3)
60
Absolute count reference ranges
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
Shift to the Left
Increase in young forms of WBCs, 2 types: Degenerative and Regenerative
62
Degenerative Shift to the Left
Increase in young forms, seen in tuberculosis, normal/decreased WBC count
63
Regenerative Shift to the Left
Increase in young forms, seen in appendicitis, WBC count elevated
64
Shift to the Right
Increase in old forms of neutrophils, seen in pernicious anemia
65
Leukoerythroblastic Reaction synonyms
Leukoerythroblastosis, Leukoerythroblastic anemia
66
Leukoerythroblastic Reaction key features
Immature neutrophils, nucleated RBCs, teardrop RBCs
67
Leukoerythroblastic Reaction accompanied by neutrophilia
Often, but not always
68
Leukoerythroblastic Reaction significance
Nonspecific, indicates underlying disease or stress to hematopoietic compartment
69
Leukoerythroblastic Reaction association with PMF
Strongly associated with primary myelofibrosis
70
Leukoerythroblastic Reaction in myelophthisis
Seen in metastatic tumor, fibrosis, lymphoma, leukemia
71
Leukoerythroblastic Reaction in mild cases
Observed in hemolytic anemia, severe infections, cardiac failure, uremia, megaloblastic anemia
72
Smudge cells appearance
Nuclear remnants of lymphocytes, thumbprint shape, structureless chromatin
73
Smudge cells normal occurrence
Found in few numbers, may be associated with chronic lymphocytic leukemia (CLL)
74
Basket cells appearance
Nuclear remnants of granulocytic cells, netlike chromatin pattern
75
Basket cells normal occurrence
Found in few numbers, may be seen in some leukemias
76
Necrotic cells description
Granulocytic cells with pyknotic nuclei, agranular cytoplasm
77
Necrotic cells cause
Prolonged exposure to EDTA, rarely chemotherapy
78
Phagocytic cells description
Neutrophils engulfing foreign bodies like bacteria and fungi
79
Phagocytic cells association
Overwhelming septicemia, bacterial and fungal infections, erythrophagocytosis
80
Endothelial cells description
Large cells (20 to 30 um), stretched and ovoid appearance, single nucleus with dense chromatin
81
Endothelial cells appearance
Abundant translucent cytoplasm, no nucleoli, usually found at feather edge
82
Endothelial cells occurrence
Contaminant of venipuncture, occasionally found in blood obtained by venipuncture
83
Endothelial cells distinction
Must not be confused with clumps of malignant cells
84
Megakaryocyte fragments description
Nude nuclei, dark purple staining
85
Megakaryocyte fragments occurrence
Found in newborns, aberrant platelet production, myelofibrosis, essential thrombocythemia
86
Nucleated red blood cells (NRBCs) description
Varies with cell maturity
87
Nucleated red blood cells (NRBCs) occurrence
Found in newborns, hemolysis, leukemia, myeloproliferative disorders
