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🩸Hema🎀 > 7: Laboratory Diagnosis of Coagulation > Flashcards

7: Laboratory Diagnosis of Coagulation Flashcards

(56 cards)

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1
Q

Was the first laboratory procedure designed to assess coagulation

A

Lee-White Whole Blood Coagulation Time Test

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2
Q

Principle: The time interval from the initiation of clotting to visible clot formation reflects the condition of the coagulation mechanism

A

Lee-White Whole Blood Coagulation Time Test

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3
Q

Is still widely used as a POCT

A

Activated Clotting Time (ACT) Test

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4
Q

Screening Test

A
  1. Prothrombin Time
  2. Partial Thromboplastin Time
  3. PTT Mixing Studies
  4. Thrombin Clotting Time
  5. Venom Activated Assays
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5
Q

Reagents of PT

A

Thromboplastin
Phospholipids
Calcium Chloride

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6
Q

Recombinant or affinity-purified tissue factor suspended in phospholipids mixed with a buffered 0.025 M solution of calcium chloride

A

Prothrombin Time (PT)

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7
Q

It is most sensitive to factor VII deficiencies

A

Prothrombin Time (PT)

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8
Q

Is used most often to monitor the effects of therapy with Warfarin/Coumadin

A

Prothrombin Time (PT)

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9
Q

PT is typically reported as a combination of

A

PT (in seconds) and INR (as PT/INR)

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10
Q

PT Typical reference interval:

A

12.6- 14.6 seconds

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11
Q

Determine extrinsic and common pathway factor deficient

A

Prothrombin Time (PT)

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12
Q

Indicate if Normal or Decreased in Vitamin K deficiency

Factor V -
Factor VII -

A

Factor V - Normal
Factor VII - Decreased

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13
Q

Indicate if Normal or Decreased in Liver Disease

Factor V -
Factor VII -

A

Factor V - Decreased
Factor VII - Decreased

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14
Q

INR

A

International Normalized Ratio

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15
Q

ISI

A

International Sensitivity Index

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16
Q

INR formula:

A

INR = Patient or test PT x 100
———————————
Mean or Control PT

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17
Q

Is employed to monitor the effects of UFH and to detect LAC and specific coagulation factor antibodies(anti-factor VIII antibody)

A

Partial Thromboplastin Time (APTT)

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18
Q

Is prolonged in all congenital and acquired procoagulant deficiencies (except VII and XIII)

A

Partial Thromboplastin Time (APTT)

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19
Q

Partial Thromboplastin Time (APTT) Reference value:

A

26-38 seconds

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20
Q

Determined intrinsic and common pathway factor deficient

A

Partial Thromboplastin Time (APTT)

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21
Q

Monitors unfractionated heparin therapy

A

Partial Thromboplastin Time (APTT)

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22
Q

PTT reagent contains:

A
  • Phospholipid
  • Negatively charged particulate activator (kaolin, ellagic acid, silica, or celite)
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23
Q

Distinguish LACs from specific inhibitors and factor deficiencies

Study These Flashcards
A

PTT Mixing Studies

24
Q

Commercially prepared bovine thrombin reagent cleaves fibrinopeptides A and B from plasma fibrinogen to form a detectable fibrin polymer

Study These Flashcards
A

Thrombin Clotting Time

25
Test for fibrinogen deficiency
Thrombin Clotting Time
26
Is used to determine whether UFH is present whenever the PTT is prolonged
Thrombin Clotting Time
27
Thrombin Clotting Time Typical reference range:
15-20 seconds
28
Thrombin Clotting Time is prolonged when:
- Fibrinogen is <100 mg/dL (hypofibrinogenemia) - Presence of antithrombotic materials (FDP, paraproteins, or UFH) - Presence of antithrombotic materials (FDP, paraproteins, or UFH)
29
May also assess the presence of the oral direct thrombin inhibitor dabigatran
Thrombin Clotting Time
30
a thrombin-like enzyme isolated from the venom of Bothrops atrox (lancehead viper)
Reptilase Time
31
Cleaves fibrinopeptide A only
Reptilase Time
32
Principle: reptilase catalyzes the conversion of fibrinogen to fibrin. In contrast to thrombin, this enzyme cleaves only fibrinopeptide A
Reptilase Time
33
Insensitive to UFH and FXIII deficiency but is markedly prolonged in dysfibrinogenemia
Reptilase Time
34
Useful for detecting hypofibrinogenemia or dysfibrinogenemia
Reptilase Time
35
Also prolonged in the presence of FDP and paraproteins
Reptilase Time
36
Reptilase Time Reference value
10-15 seconds
37
Test for fibrinogen deficiency/fibrinogen abnormality and It is not affected by Heparin/Heparin therapy
Reptilase Time
38
triggers coagulation at the level of factor X
Russell Viper Venom Test
39
is used to detect and confirm lupus anticoagulant.
Diluted Russell Viper Venom Test (DRVVT)
40
Determines coagulation factor deficiency in the common pathway
Russell Viper Venom Test
41
A modification of TCT and is the recommended procedure for estimating fibrinogen function
Fibrinogen Assay
42
The interval to clot formation is inversely proportional to the concentration of functional fibrinogen
Fibrinogen Assay
43
Reagents of Fibrinogen Assay:
- Owren buffer - Bovine thrombin
44
Factor VIII-depleted or –deficient PPP provides normal activity of all procoagulants except factor VIII
Single-Factor Assay using the PTT
45
Single-Factor Assay using the PTT: Factor VIII-depleted PPP (alone):
prolonged PTT (Factor VIII deficiency)
46
Single-Factor Assay using the PTT: Factor VIII-depleted PPP + Normal patient plasma:
PTT reverts to normal (Coagulation Factor Deficiency)
47
Single-Factor Assay using the PTT: Factor VIII-depleted PPP + Factor VIII-deficient patient plasma:
Prolonged (LAC)
48
Confirms and quantifies anti-factor VIII inhibitor (typically IgG4-class immunoglobulin)
Nijmegen-Bethesda Assay
49
Is expressed as a percentage of the control
Bethesda titer
50
The percentage of factor VIII activity neutralized is proportional to the level of inhibitor activity
Bethesda titer
51
The principles and procedures described in the section on single-factor assay using the PTT system may be applied except that PT reagent replaces the PTT reagent in the test system, and the PT protocol is followed.
Single Factor Assays using the PT
52
Quantification of factor XIII activity is based on the measurement of ammonia released during an in vitro transglutaminase reaction
Factor XIII Assays
53
Decreased VWF:Ag, VWF:RCo, and Factor VIII:C
VWD Type I and III
54
Decreased VWF:Ag, Factor VIII:C
VWD Subtypes 2A, 2B, 2M
55
Decreased Factor VIII:C
Subtype 2N
56
Give the clotting factor deficient in the following tests: Nijmegen-Bethesda: TCT: Stypven Time (RVVT): Reptilase Test: Clause Test: Technochron:
Nijmegen-Bethesda: Anti-factor VIII inhibitor TCT: Factor I (affected by heparin) Stypven Time (RVVT): Factor X Reptilase Test: Factor I (unaffected by heparin) Clauss Test: Factor I Technochron: Factor XIII

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