Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HEMATOLOGY 2 > Common Tests for primary hemostasis > Flashcards

Common Tests for primary hemostasis Flashcards

1
Q

Reasons platelets are hard to count

A

Adhere to foreign surfaces, easily disintegrate, hard to differentiate from debris, unevenly distributed due to clumping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Normal platelet count (general)

A

150 to 450 x 10^9/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Platelet count decrease after 65 years

A

122 to 350 x 10^9/L in men, 140 to 379 x 10^9/L in women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Platelet count < 100,000/µL

A

Most common cause of clinically important bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Phase-contrast microscope method reference

A

Described by Brecher and Cronkite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

EDTA whole blood dilution for phase-contrast

A

1:100 with 1% ammonium oxalate to lyse RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Platelets counted in phase-contrast method

A

25 small squares of central large square (1 mm²) in hemocytometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Verification of manual thrombocyte count

A

Estimate on Wright-stained PBS made from same specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Alternate method to count platelets

A

Light microscope, but harder to visualize platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Reference method for platelet count

A

Phase-contrast microscope method by Brecher and Cronkite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Dilution for phase-contrast method

A

1:100 with 1% ammonium oxalate (lyses nonnucleated RBCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Area for platelet count in hemocytometer

A

25 small squares of the central large square (1 mm²)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Accuracy verification for manual count

A

Estimate on Wright-stained PBS from the same specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Alternate method for platelet visualization

A

Light microscope (more difficult to visualize platelets)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Platelet characteristics under phase-contrast microscopy

A

Diameter: 2-4 µm, Shape: round/oval, Color: light purple sheen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Background feature often seen in phase-contrast microscopy

A

Ghost erythrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Counting area for platelets in hemocytometer

A

25 small squares of the central large square (1 mm²)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Acceptable difference in counts between sides of hemocytometer

A

< 10% difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Action for uneven platelet distribution

A

Repeat the procedure if > 10% difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Anticoagulant used for phase-contrast platelet count

A

1% ammonium oxalate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Purpose of placing charged hemocytometer in a moist chamber

A

Allows platelets to settle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Components of a moist chamber

A

Damp filter paper in a Petri dish, applicator stick as support

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Incubation time for platelets in the moist chamber

A

15 minutes

24
Q

Formula for percentage difference

A

[(V1 - V2) / (V1 + V2 ) x 100]

25
Q

General formula for manual cell counts (average of platelet count should be counted on two sides)

A

PLT count (cells/µL) = (cells counted x dilution factor) / (area (mm²) x depth (0.1))

26
Q

Examine the thin area where

A

a few RBCs slightly overlap under oil immersion.

27
Q

Normal platelet count per 100x field on a wedge smear

A

Approximately 7 to 21 platelets.

28
Q

Platelet estimation formula

A

Average platelets/OIF x 20,000 = estimated platelet count (µL).

29
Q

Adjusted platelet estimation formula

A

(Average platelets per field x total RBC count) / 200 RBCs per field.

30
Q

Topic

A

Details

31
Q

200 in adjusted formula represents

A

Average RBCs per oil immersion field in the optimal assessment area.

32
Q

Platelet estimate of 0 to 49,000/µL; qualitative report

A

marked decrease

33
Q

Platelet estimate of 50,000 to 99,000/µL; qualitative report

A

moderate decrease

34
Q

Platelet estimate of 100,000 to 149,000/µL; qualitative report

A

slight decrease

35
Q

Platelet estimate of 150,000 to 199,000/µL; qualitative report

A

low normal

36
Q

Platelet estimate of 200,000 to 400,000/µL; qualitative report

A

normal

37
Q

Platelet estimate of 401,000 to 599,000/µL; qualitative report

A

slight increase

38
Q

Platelet estimate of 600,000 to 800,000/µL; qualitative report

A

moderate increase

39
Q

Platelet estimate above 800,000/µL; qualitative report

A

marked increase

40
Q

Designed to test platelet-rich plasma (PRP)

A

light-transmittance (optical) platelet aggregometry

41
Q

Centrifuge requirement for PRP

A

50 x g for 30 minutes

42
Q

PRP specimen storage

A

18 to 24°C until test

43
Q

PRP aggregometry initiation

A

No less than 30 minutes, within 4 hours

44
Q

Minimum whole blood volume needed for adequate PRP

A

9 to 12 mL

45
Q

Light-transmittance aggregometry is unreliable when whole-blood platelet count is

A

< 100,000/µL

46
Q

PRP amount with a platelet count of

A

200,000 to 300,000/µL

47
Q

Aggregating reagents ACE

A

ADP, Collagen, Epinephrine/adrenaline

48
Q

Normal response to ACE

A

BSS and vWF disease

49
Q

Abnormal response to ACE

A

Glanzmann’s thrombasthenia

50
Q

Ristocetin normal response

A

Glanzmann’s thrombasthenia

51
Q

Ristocetin abnormal response

A

BSS and vWF

52
Q

Measures platelet aggregation and ATP release (from dense granules)

A

Platelet lumiaggregometry

53
Q

Specimen for platelet lumiaggregometry

A

Whole blood diluted with saline

54
Q

Reagent for platelet lumiaggregometry

A

Luciferin-luciferase

55
Q

Source of luciferin-luciferase

A

Firefly

HEMATOLOGY 2 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions