CHAPTER 1 - HEMOSTASIS PART 7 Flashcards

1
Q

must be avoided

A

Hemolysis

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2
Q

Rbc contains(platelet activator)

A

ADP

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3
Q

May cause premature activation of
platelet if released in the plasma

A

Hemolysis

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4
Q

is the anticoagulant of choice (except for glass bead retention test)

A

Citrate

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5
Q

pH is very critical and easily affected by recapping method

A

Citrate

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6
Q

pH is best controlled by this buffer

A

Citrate

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7
Q

glass bead retention test should
contain

A

heparin

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8
Q

sample (anticoag) → 60-100 x g → 10 minutes Plasma → plastic/siliconized test tube

A

Platelet Rich Plasma (PRP) preparation

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9
Q

stored in RT (not refrigerated nor incubated)

A

Platelet Rich Plasma (PRP) preparation

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10
Q

red cell contamination = hemolysis = release of ADP

A

Platelet Rich Plasma (PRP) preparation

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11
Q

upper layer that is not touching the red cell

A

Platelet Rich Plasma (PRP) preparation

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12
Q

sample (remains) → 2000 x g for 10 minutes Plasma → plastic/siliconized test tube

A

Platelet Poor Plasma (PPP) preparation

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13
Q

layer almost in contact w/ the red cell

A

Platelet Poor Plasma (PPP) preparation

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14
Q

upper 3⁄4 layer

A

Platelet Poor Plasma (PPP) preparation

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15
Q

-samples are centrifuged at 2-4 deg celcius

A

beta-Thromboglobilin (bTG) and PF4 determinations

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16
Q

cold (not RT)

A

beta-Thromboglobilin (bTG) and PF4 determinations

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17
Q

most stable b/w:

A

30 minutes to 3 hours

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18
Q

performed 1st

A

-Ristocetin

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19
Q

plt responds to ristocetin will decerase as the pH of the plasma changes

A

-Ristocetin

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20
Q

as soon as blood is exposed to air after centri, blood pH will start to decrease, hence aggregation will be affected

A

-Ristocetin

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21
Q

performed last

A

Epinephrine

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22
Q

response w/ plt increases w/ time

A

Epinephrine

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23
Q

tales 60 mins to take effect

A

Epinephrine

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24
Q

: more sensitive to aggregating agents than @ 37 deg cel

A

platelets @ room temp

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25
Q

sensitive to RT making them more aggregatable than inside the body

A

platelets @ room temp

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26
Q

plts prepared for aggregation studies
due to sensitivity to various
aggregating agents

A

platelets @ room temp

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27
Q

spontaneous aggregation

A

platelets @ 0-4 deg

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28
Q

beta-Thromboglobilin (bTG) and PF4
determinations

A

platelets @ 0-4 deg

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29
Q

Measures the ability of the small blood vessels to control bleeding after injury

A

. Bleeding time

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30
Q

Factors affecting BT
: number of platelets and the ability of platelets to form (?); Thickness and vascularity of the skin and the ability of the blood vessels to (?) may also affect results.

A

plugs

constrict

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31
Q

Prolonged: when platelet count is lower than (?)or when platelets are dysfunctional.

: in Vwd
: after ingestion of aspirin/aspirin-containing compounds, anti-inflammatory, anticoagulants, and some antibiotics

A

30 - 50, 000/uL

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32
Q

Puncture is done on the earlobe. bleeding ceases.

A

Duke method

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33
Q

Reference value: 1 - 3 mins

A

Duke method

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34
Q

Done on the forearm; Standard pressure applied is 40 mmHg

A

Ivy method

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35
Q

• Reference value: 1 - 7 mins.

A

Ivy method

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36
Q

Uses a template containing a standardized slit

A

Template BT (by Mielke)

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37
Q

Platelet adhesiveness/Retention Test
→ Reference values:

A

26% - 60%

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38
Q

3 substances required by platelet to adhere successively:

A

Ionized Calcium, Fibrinogen, ADP

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39
Q
  • (?) is not required in vitro/initial adhesion, but required for longer retention and accurate measurement, along w/ ADP
A

VWF

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40
Q

: involves the formation of plt aggregates in the column (long rubber tubing) where platelet adhesion test will take place; measurement of retained platelets

A
  • Retention
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41
Q

enhances plt retention

A

RBC

42
Q

→ Collect 2 whole blood samples, 1 using EDTA and the other using glass bead collecting system.

A

Glass Bead Method/Salzman Method

43
Q

Perform platelet counts separately. (higher in EDTA

A

Glass Bead Method/Salzman Method

44
Q

-Collect in 2 tubes (EDTA and glass bead collecting system)

A

Glass Bead Method/Salzman Method

45
Q
  • Counts are higher in EDTA
A

Glass Bead Method/Salzman Method

46
Q

→ Perform separate platelet count on venous blood and capillary blood samples. % = plate count aust our Vet count callary blood x 100

A

Borshgervinct Method (in vivo test)

47
Q

→ Clinical Significance of platelet adhesiveness

A

Borshgervinct Method (in vivo test)

48
Q

⁃ Glanzmann’s thrombasthenia; Chediak

A

Decrease platelet adhesiveness

49
Q
  • Higashi syndrome
A

Decrease platelet adhesiveness

50
Q

⁃ Some myeloproliferative disorders; Uremia

A

Decrease platelet adhesiveness

51
Q

⁃ Ingestion of aspirin and other drugs

A

Decrease platelet adhesiveness

52
Q

⁃ Venous thrombosis; Pulmonary embolism; Carcinoma

A

Increase platelet adhesiveness

53
Q

⁃ During pregnancy; Following splenectomy; Oral contraceptive intake

A

Increase platelet adhesiveness

54
Q

-Involves platelet count on venous and capillary blood samples.

A

Borshgervinct Method (in vivo test)

55
Q

-Venous Thrombosis

A

INCREASE

56
Q

-Pulmonary Embolism

A

INCREASE

57
Q

-Carcinoma

A

INCREASE

58
Q

-During pregnancy

A

INCREASE

59
Q

-Splenectomy

A

INCREASE

60
Q

-Oral contraception

A

INCREASE

61
Q

-Glanzmann’s Thrombasthenia

A

DECREASE

62
Q

-Chediak

A

DECREASE

63
Q

Higashi

A

DECREASE

64
Q

Myeloproliferative disorders

A

DECREASE

65
Q

Uremia

A

DECREASE

66
Q

-Aspirin and other drugs

A

DECREASE

67
Q

Aggregating agents:

A

thrombin, arachidonic acid, ADP, collagen,
epinephrine and ristocetin

68
Q

→ Currently, this test is considered the gold standard for evaluation of aspirin resistance

A

Platelet Aggregation Test

69
Q

Principle of Aggregation

Aggregating agents added to a stirred suspension of (?) induce a shape change and aggregation of platelets. As a result, the PRP changes from a turbid suspension to one that transmits more light (clear) as the aggregates are formed. The aggregometer records changes in (?) in the form of a graph.

A

PRP

optical density

70
Q

Aggregating agents added to PRP→ induces shape change and aggregation → PRP changes from turbid to clear (transmits more light) as aggregates are
formed → optical density is recorded
by aggregometer.

A

Principle of Aggregation

71
Q

:light-transmittance aggregometer

A

Platelet-Rich Plasma Aggregometry

72
Q

: electrical impedance

A

Whole-Blood Platelet Aggregometry

73
Q

for simultaneous measurement of platelet aggregation and the secretion of ATP

A

Optical Lumi-Aggregometer.

74
Q

Tests the ability of small capillaries to retain blood when subjected to increased hydrostatic pressure and
anoxia.

A

Tourniquet test/Capillary Fragility test)

75
Q

Nonspecific screening test

A

Tourniquet test/Capillary Fragility test)

76
Q

Principle: an inflated blood pressure cuff on the upper arm is used to apply pressure to the capillaries for 5 minutes.

A

Rumple-Leede Method (Positive pressure)

77
Q

The forearm, hands and fingers are then examined for petechiae

A

Rumple-Leede Method (Positive pressure)

78
Q

Rumple-Leede Method (Positive pressure) Normal:

A

0 to occasional petechiae

79
Q

uses positive pressure

A

Rumple-Leede Method (Positive pressure)

80
Q

A suction cup (diameter) is placed in close contact with the skin at midpoint of upper arm for (?). An area within a circle of (?) diameter is observed for petechiae (?) after removal of suction cup.

A

Hess/Suction test (Negative pressure)

2-cm

1 min (pressure of 200 - 250 torr)

1 cm

5 minutes

81
Q

Hess/Suction test (Negative pressure)
● Clinical significance: Positive in

A

thrombocytopenia, hypofibrinogenemia and in vascular purpura.

82
Q

● -uses negative pressure

A

Hess/Suction test (Negative pressure)

83
Q

-Uses suction cup (2-cm diameter) → midpoint of upper arm → 1 min (200-
250 torr) → 1 cm diameter area is observed after 5 minutes of suction cup removal

A

Hess/Suction test (Negative pressure)

84
Q

Clot Retraction Principle: When blood coagulation is complete, clot normally undergoes retraction where clot becomes denser and serum is expressed. Normally, clot retraction begins within (?) after the blood has clotted & complete within (?)

A

30 minutes

24 hours.

85
Q

● Normal clot retraction requires

A

normal number of functioning platelets, Ca*, ATP, fibrinogen, normal interaction of the platelets with fibrinogen

86
Q
  • ratio of the plasma volume and red cell mass; activity of a retraction-promoting principle in serum
    & nature of the surface on which CRT
    is being measured.
A

Thrombosthenin

87
Q

Clinical significance: CRT is poor
when platelet count is less than 100,000/uL; in dysfibrinogenemia or hypofibrinogenemia, paraprotinemias

A

Clot Retraction

88
Q

Qualitative: Test for the presence or
absence of retraction

A

Hirschboeck Method (Castor oil Method)

89
Q

● Formation of dimpling/droplet like
serum on the surface of blood drop

A

Hirschboeck Method (Castor oil Method)

90
Q

● Normal Values = 15 - 45 minutes

A

Hirschboeck Method (Castor oil Method)

91
Q

● Normal: clot retraction begins within 1
hour, complete within 18 to 24 hours

A

Stefanini Method (Test tube)

92
Q

● Provides quantitative estimate of the degree of retraction

A

Mac Farlane Method

93
Q

● Normal Values = 44% - 67 %

A

Mac Farlane Method

94
Q

• Sodium citrate - anticoagulant

A

Tocantins Method (Rees -Ecker diluting fluid composition)

95
Q

• Formalin - fixative; prevent premature lysis (preserves both red cells and platelets)

A

Tocantins Method (Rees -Ecker diluting fluid composition)

96
Q

• BCB - stains the platelets

A

Tocantins Method (Rees -Ecker diluting fluid composition)

97
Q

• Brecker - Cronkite Method (Diluent: 1% NH4 oxalate)

A

Phase - Contrast Microscopy Method

98
Q

• Counting chamber: Spencer — Briteline # 1475

A

Phase - Contrast Microscopy Method

99
Q

• Platelets are counted in 5 R squares

A

Phase - Contrast Microscopy Method

100
Q

• Uses EDTA and ammonium oxalate Diluent

Composition:

A

Unopette Method

0.44% NHa oxalate; 0.22% K: EDTA; 0.75% Crystal Violet

101
Q

• Uses 14% MgSO4 as diluent

A

Fonio’s Method