L1 ( NOTES ONLY) Flashcards
(123 cards)
1
Q
shape of normal platelets when resting
A
biconvex
2
Q
average diameter of platelets
A
2.5 um (2-4 um)
3
Q
normal platelet count of platelet
A
150-450 x10^9/L
4
Q
How many platelets are in circulation
A
2/3
5
Q
How many platelets are squestered in spleen
A
1/3
6
Q
What happens to platelets in EDTA tube
A
round up
7
Q
appearanceof Platelets in peripheral blood film
A
circular to irregular,lavender,anuclear,granular
8
Q
these appear in compensation for thrombocytopenia
A
Reticulated/Stress Platelets
9
Q
size of Reticulated/Stress Platelets
A
6um
10
Q
normal mean platelet volume
A
8-10 fL
11
Q
mean platelet volume in citratee blood
A
5-7 fL
12
Q
mean platelet volume of reticulsted/stress platelets
A
12-14 fL
13
Q
platelets arise from
A
Megakaryocytes
14
Q
largest cells in the BM
A
Megakaryocytes
15
Q
term for having multiple chromosome copies
A
polypoid
16
Q
Megakaryocytes comprise - of all BM cells
A
<0.5%
17
Q
number of megakaryocytes seen in normal BM aspirate
A
2-4 megakaryocytes/LPF
18
Q
maturation time of megakaryocytes in the BM
A
4-5 days
19
Q
life span of platelets in the peripheral circulatioon
A
9-12/8-10 days
20
Q
number of platelets in 1 liter (L) or 1 microliter (uL) of whole blood
A
platelet count
21
Q
reasons why platelets are hard to count
A
Platelets adhere to foreign surfaces.
Platelets easily disintegrate.
They are hard to differentiate from debris.
Platelets are unevenly distributed in the blood because they tend to clump.
22
Q
princiole of manual platelet count
A
Whole blood, with EDTA as the anticoagulant,
is diluted with platelet diluting fluid in an
RBC pipet and counted using the
hemocytometer. The platelets are counted in
the 25 small squares in the large center
square (1 mm2) of the hemocytometer using
phase-contrast microscope or light microscope
23
Q
platelet for manual platelet count are diluted using
A
platelet diluting fluid
24
Q
pipet used for manual platelet count
A
RBC pipet
25
instrument used for counting manual platelet count
hemocytometer
26
what part of the hemocytometer are platelets counted
25 small squares in the large center square (1 mm ^2)
27
Microscope used for manual platelet count
phase-contrast microscope or light microscope
28
specimen of choice for manual platelet count
venous blood anticoagulated with edta
29
methods for manual platelet count
Indirect and direct method
30
method of manual platelet count wherein they are counted in relation to 1,000 RBCs in the blood smear
Indirect method
31
method of manual platelet count wherein whole blood is diluted with platelet diluting fluid in an RBC pipette and counted in a hemocytometer
Direct Method
32
2 types of direct method in manual platelet count
Light Microscopy Method and Phase Microscopy Method
33
types of Light Microscopy Method
Rees and Ecker's Method and Guy and Leake's Method
34
diluting fluid (isotonic) composition in Rees and Ecker's method
Sodium Citrate,Formaldehyde,Brilliant Cresyl blue,Distilled Water
35
composition of Diluting fluid in Rees and Ecker's method that prevents platelet aggregation
Sodium Citrate
36
preservatice composition of diluting fluid in Rees and Ecker's
Formaldehyde
37
stain/dye in the diluting fluid in Rees and Eckers
Brilliant Cresyl Blue
38
appearance of plstelets in Rees and Ecker's
small|round/ oval| highly refractile | bluish
39
diluting fluid (isotonic) composition of Guy and Leake's method
Sodium Oxalate,Formaldehyde,Crystal Violet,Distilled Water
40
composition of the diluting fluid of the guy and Leake's method that prevents platelet aggregation
Sodium oxalate
41
composition of the diluting fluid of the guy and leake's method that serves as preservative
formaldehyde
42
composition of the diluting fluid of the guy and leake's method that serves as stain/dye
Crystal violet
43
apoearance of platelets in guy and leake's method
highly refractile | lilac
44
lyses RBCs and allows platelets to form pseudopods
1% ammonium oxalate
45
types of phase microscopy method
Brecher-Cronkite Method,Unopette,Tocantin's Method,Nygard's Method,Walker and Sweeney's Method
46
composition of the diluting fluid in Brecher-Cronkite Methid
1% ammonium oxalate (hyoitonic)
47
appearance of platelets in Brecher-Cronkite Method
small (2-4 um)| round/oval | displays a light purple sheen
48
sample in Rees and Ecker's method should be drawn up to - mark of the RBC Pipette
0.5 mark
49
how many minutes shoukd the charged hemocytometer be placed in a moist chamber in Rees and Ecker's Method
10- 15 minutes
50
in manual platelet counting using Rees and ecker the difference between total counts from each side of hemocytometer should be
less than 10%
51
performed to verify manual platelet count
platelet estimate
52
ratio of dilution in Breacher and Cronkite Method
1 : 100
53
1 : 000 dilution in brecher and cronkite is composed of
20 uL Blood + 1980 uL (1% ammonium oxalate)
54
counting chamber chamber used in phase-microsocopy platelet count
special thin,flat-bottomed
55
In brecher and Cronkite method,what objective lens is used in counting platelets
HPO
56
Most common ratio of dilution
1 : 100
57
dilution when less thsn 50 platelets counted on each side
1 : 20
58
dilution when greater than 500 platelets are counted on each side
1 : 200
59
formula for platelet counting using in Manual Platelet count
platelet count = (cells counted x dilution fsctor)/ (area counted (mm2) x depth)
60
normal values or reference range in manual platelet counting in adult (conventional units)
150,000 - 450,000 cells/mm3 or cells / uL
61
normal values or reference range in manual platelet counting in adult (SI)
150-450 X10^9/L
62
when there is normal platelet, how many rbc squares can be counted
5
63
area counted when it is assumed for the patient to have normal plstelet count
0.2 mm2
64
if blood is not stored at RT it shoukd be diluted within
5 HOURS OF COLLECTION
65
if blood is stored at RT it should be diluted within
24 hours
66
inadequate mixing or poor collection results to - in manual platelet count
platelet clumping
67
platelet clumning causes platelet count to
falsely decrease
68
short draw:excess anticoagulant causes plstelets to
swell = fragmentation
69
fragmentation will cause manual platelet count to
falsely increase
70
adherance of platelets around neutrophils,producing a ring or satellite effect
Platelet satellitosis
71
Platelet Satellitosis usually occurs in
EDTA Anticoagulated samples
72
platelet satellitosis causes platelet counting using to
pesudothrombocytopenia
73
solution when there is Platelet satellitosis
use sodium citrate as anticoagulant; multiply the obtained platelet count by 1.1 for accuracy
74
hematology instrument with principle impedence volume and conductivity and five- angle light scatter movement
Beckman Coulter Unicel DxH 800
75
hematology instrument with principle impedance; light scatter; fluorescent staining,forward light scatter, and side fluorescent light detection
Sysmex XN Series
76
hematology instrument with principle Dual-angle light scatter analysis;impedamce count for verification; optional CD61 monoclonal antibody count
Abbott CELL-DYN Sapphire
77
hematology instrument with principle Low-angle amd high value light scartwe; refractive index
Siemens ADVIA 2120i
78
in EDTA blood during automated platelet counting when is MOV relatively stable
bet. 1 and 3 hours
79
What happens in MPV in edta specimen in automated platelet count if left more than 3 hours
increases
80
presence of microcytes or schistocytes will make automated platelet count
increase
81
platelet clumps will make automated platelet count
decreased
82
leukemia will make automated platelet count
increased
83
old specimen will make automated platelet count
decreased
84
disposable blood cell count dilution system
Leukocheck
85
example of capillary pipette and diluent reservoir system which is commercially available for
WBC and platelet counts.
Leukochek
86
specimen in Leukocheck method
EDTA- anticoagulated whole blood or blood obtained from capillary puncture
87
REAGENT AND MATERIALS IN LEUKOCHECK
Plastic Reservoir,Capillary Pipette,Hemacytometer and coverslip
88
plastic reservoir in Leukocheck shoukd contain
1.98 mL of 1% buffered ammonium oxalate
89
capillary pipette is calibrated to accept (blood)
20 uL of blood
90
dilution ratio in Leukocheck
1: 100
91
objective lens used in platelet estimate (pbs)
100x oil immersion objective
92
formula to obtain platelet estimate per uL of blood
average number of platelets x 20,000
93
how many fileds should be counted in platelet estimate
10 consecutive fields
94
instances of significant anemia or erythrocytosis, use the following formula for the platelet estimate
Average no. of platelets × total RBC count/ 200 RBCs
95
if platelet count is normal there must be
about 1 platelet per 10-30 blood cells and 7-21 platelets per oil immersion field
96
markedly decrease platelet
0 to 49,000 per uL
97
moderately decreased platelet
50,000 to 99,000 per uL
98
Slightly decreased platelet
100,000 to 149,000 per uL
99
Low normal platelet
150,000 to 199,000 per uL
100
normal platelet count in pLatelet estimate
200,000 to 400,000 per uL
101
slightly increased
401,000 to 599,000 peruL
102
moderately increased
600,000 to 800,000 per uL
103
markedly increased
greater than 800,000 per uL
104
solution for errors caused by microcytes and schistocytes in automated platelet count
review blood film
105
instrument indicators for microcytes or schistocytes in automated plstelet count
Left shift on RBC Histogram,MCV Flagged if less than limits;abnormal PLT histogram may be flagged
106
rationale on the oresence if microcytes or schistocytes during automated platelet counting
volume of RBs or RBC Fragments less rhan lower RBC Threshold,and/or within PLT threshold
107
parameters affected in the oresence of microcytes or schistocytes
108
solution for errors caused by platelet clumps in automated platelet count
redraw specimen in sodium citrate;multiply result by 1.1
109
instrument indicators for platelet clumps in automated plstelet count
Platelet clumps/ N flag,Interference at nouse-lymphocytw interferance on histogram/cytogram
110
rationale on the oresence of platelet clumps during automated platelet counting
large clumps counted as WBCs not platelets
111
parameters affected in the presence platelet clumps
decreased plstelet clumps amd Increased WBC
112
solution for errors caused by Leukemia (esp, with chemotherapy )in automated platelet count
review film,perform phase platelet count
113
instrument indicators for Leukemia (esp, with chemotherapy ) in automated plstelet count
platelet count inconsistent with previous results
114
rationale on the oresence of Leukemia (esp, with chemotherapy ) during automated platelet counting
Fragile WBCs,fragments counted as platelets
115
parameters affected in the oresence of Leukemia (esp, with chemotherapy )
Decreased WBC, increased PLT
116
solution for errors caused by Old Specimen in automated platelet count
Establish stability amd specimen rejection criteria
117
instrument indicators for Old Specimen in automated plstelet count
abnormal clusterimg om WBC histogram/cytogram
118
rationale on the Old Specimen during automated platelet counting
RBCs swell as specimen ages, platelets swell and degenerate,WBCs affected by prolonged exposure to EDTA
119
parameters affected in Old Specimen
Increased MCV,Increased MPV, decreased PLT, automated differential may be incorrect
120
counted in all 9 large squares (9 mm2) using low power
WBCs
121
counted in the 25 small squares in the center square (1 mm2) using high power
Platelets
122
solutuin in Leukocheck method are allowed to stand for - to allow lysis of red blood cell
10 minutes
123
discared from the diluted sample in leukocheck
3 to 4 drops
