International Normalize Ratio Flashcards

1
Q

This is a standardized way of reporting PT in monitoring
oral anticoagulant therapy, calculated as a ratio of the
patient’s PT to a control PT standardized for the potency
of the thromboplastin reagent developed by the World
Health Organization

A

International Normalized Ratio

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2
Q

Formula of INR?

A

𝐼𝑁𝑅 = {(π‘π‘Žπ‘‘π‘–π‘’π‘›π‘‘ 𝑃𝑇) / 𝑃𝑇 (π‘π‘œπ‘›π‘‘π‘Ÿπ‘œπ‘™ π‘šπ‘’π‘Žπ‘›} 𝐼𝑆I

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3
Q

International Sensitivity Index stands for?

A

ISI

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4
Q

(calibration index) and indicated on the reagent bottle?

A

ISI

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4
Q

high risk for bleeding; blood is thin means Greater or Lesser INR?

A

Greater than INR

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4
Q

Reference values for INR for 2.0-3.0?

A

β–  In prevention and treatment of venous
thrombosis
β–  Treatment of pulmonary embolism
β–  Prevention of stroke in myocardial infarction
β–  Peripheral arterial disease
β–  Prevention of systemic embolism in atrial
fibrillation
β–  Cardiac valve replacement (tissue valve)

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5
Q

High risk for thrombosis; blood is viscous means Greater or Lesser INR?

A

Less than INR

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5
Q

This uses a venom from Vipera russelli or Daboia
russelli, which has a thromboplastin-like action?

A

Stypven time or Russell viper venom test

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5
Q

Reference values for INR for 2.5-3.5?

A

β–  In prevention of recurrent MI
β–  Reduction of mortality in MI
β–  Mechanical prosthetic heart valve (high risk)

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6
Q

Stypven time or Russell viper venom test uses what venum?

A

Vipera russelli or Daboia
russelli

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7
Q

Stypven time is similar to Factor?

A

VIIa-TF complex

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8
Q

Addition of the venom bypasses the activation of
VII and directly activates factor X

A

Vipera russelli or Daboia
russelli

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9
Q

Dilute Russell viper venom time, together with APTT, is
used to test for (?) which inhibits
phospholipid

A

lupus anticoagulant

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10
Q

INDIRECT TESTS

A

Thrombin time
Reptilase time
Dukert test

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11
Q
  • This is a modification of thrombin clotting time by
    Clauss
  • This measures the availability of functional fibrinogen;
    used to monitor heparin therapy and is sensitive to the
    presence of increased levels of FSP
A

Thrombin time (fibrinogen deficiency test)

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12
Q

Other name of Thrombin time?

A

(fibrinogen deficiency test)

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13
Q

Thrombin time Specimen? and diluted to?

A

citrated PPP (diluted at 1:10)

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14
Q

Thrombin time Reagent?

A

standardized thrombin solution and calcium

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15
Q

Thrombin time Reference time

A

17-25 seconds

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16
Q

Causes of prolonged thrombin time

A

Fibrinogen level is below 75-100 mg/dL
β–  Functional disorder of fibrinogen
β–  Presence of heparin, FSP, and thrombolytic agents
β–  Normally prolonged in newborns and in multiple
myeloma

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16
Q

This uses the reagent reptilase enzyme, collected from
Bothrops atrox, which has a thrombin-like effect

A

Reptilase time

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17
Q

Reptilase time uses the reagent (?), collected from (?), which has a thrombin-like effect

A

reptilase enzyme, Bothrops atrox

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17
Q

This anticoagulant is unable to inhibit reptilase

A

Heparin

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18
Q

Reptilase time Reference time

A

18-20 seconds

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18
Q

Dukert test is also called?

A

t (5M urea solubility test)

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18
Q

Causes of prolonged reptilase time:

A

Fibrinogen deficiency and other functional
disorders of fibrinogen
β–  Presence of FSP

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19
Q
  • PT is performed on serum
  • Deficiency in factors V, VIII, IX X, XI, XII, or platelets will
    slow the rate of (?) leaving
    significant amount of prothrombin in the serum
A

Prothrombin consumption time

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19
Q

In duker test, If (?) is deficient in the patient’s plasma,
the clot is dissolved in less than (?) by the
urea

A

factor XIII, 24 hours

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19
Q

Clot formed in normal plasma is insoluble in 5M
urea during a 24-hour incubation

A

Dukert test (5M urea solubility test)

20
Q
  • If the residual prothrombin is (?), there is deficiency
    in coagulation factors
A

> 20%

21
Q

Deficiency in factors in Prothrombin consumption time?

A

factors V, VIII, IX X, XI, XII, or platelets

21
Q

Thromboplastin generation time made by?

A

Biggs and
Douglas

21
Q

This uses BaSO4/Al(OH)3-adsorbed plasma or fresh
serum

A

Thromboplastin generation time

21
Q

This is a modification of thromboplastin generation
time and requires recalcification of diluted plasma

A

Hicks-Pitney test

21
Q

: a semi-automated mechanical instrument
that detects fibrin strand formation using a wire loop or
hook and it is under what type of automation?

A

Fibrometer, Electromechanical

22
Q

Fibrometer checks for fibrin threads every (?)
which allows more accuracy

A

0.5 seconds

23
Q

This depends on the increase in light scattering
associated with the conversion of soluble fibrinogen
molecules to the insoluble polymerized fibrin clot

A

Photo-optical

24
Q

What are the Semi-automated instruments?

A

Electra 750 and 750A;
Fibrintimer series; and FP 910 Coagulation Analyzer

25
Q

what are the Automated instruments?

A

Ortho Koagulab 16S and 40A;
COag-A-Mate X2 and XC; MLA Electra 700 and 800

26
Q

This is performed when PTT and PT are prolonged to
determine whether it is caused by a nonspecific
inhibitor, specific inhibitor, or coagulation factor
deficiency, and to determine the deficient coagulation
factor

A

MIXING OR SUBSTITUTION STUDIES

27
Q

To determine if it is factor deficiency and or inhibitor, we will add?

A

Normal fresh plasma

27
Q

Fiirst to dissappear and shortest life span in vivo

A

VII

28
Q

When it become uncorrected, it means?

A

Presence of pathological circulating anticoagulant

29
Q

Under Presence of pathological circulating anticoagulant, Specific inhibitor means using?

A

perform APTT and DRVVP

29
Q

Adsorbed plasma (present)

A

I, V, VIII, XI, XII, XIII, HK, PK

30
Q

Fresh plasma (present)

A

All factors

30
Q

what is need to do in Identification of deficient factor

A

mix equal parts of
patient’s plasma + an appropriate mixing sample

31
Q

Under Presence of pathological circulating anticoagulant, Non Specific inhibitor means using?

A

. lupus anticoagulant;
Bethesda assay (screening); immunoassay
(confirmatory)

31
Q

Aged plasma (present)

A

I, II, VII, IX, X, XI, XII, XIII,
PK, HK

31
Q

if repeated test is corrected when
mixed with normal plasma, it means?

A

Factor deficiency

32
Q

Fresh plasma (absent)

A

None

32
Q

Aged plasma (absent)

A

V, VIII

32
Q

Fresh serum (absent)

A

I, V, VIII, XIII

33
Q

Fresh serum (present)

A

II, VII, IX, X, XI, XII, HK,. PK

33
Q

Adsorbed plasma (absent)

A

II, VII, IX, X

34
Q

Aged serum (present)

A

VII, IX, X, XI, XII, HK, PK

35
Q

Aged serum (absent)

A

I, II, V, VIII, XIII

36
Q

Adsorbed serum (present)

A

XI, XII, HK, PK

37
Q

Adsorbed serum (absent)

A

I, II, V, VII, VIII, IX, X, XII

38
Q

PT normal and APTT prolonged

A

Intrinsic: VIII, IX, XI, XII, HMWK, PK

39
Q

PT Prolonged and APTT prolonged

A

Common: I, II, V, X

40
Q

Sample problem:
PT and APTT: prolonged
βœ“ Adsorbed plasma
X Fresh serum

A

Factor I and V is deficient

41
Q

PT prolong and APTT normal

A

Extrinsic: VII

42
Q

Sample problem:
PT and APTT: prolonged
βœ“ Aged serum
X Adsorbed plasma

A

Factor X is deficient

43
Q

Sample problem:
PT: normal and APTT: prolonged
βœ“ Adsorbed plasma
X Fresh serum

A

Factor VIII is deficient

44
Q

Sample problem:
PT: normal and APTT: prolonged
βœ“ Aged serum
X Adsorbed serum

A

Factor IX is deficient

45
Q

(modification of thrombin time by
Clauss

A

Fibrinogen assay

46
Q

Used for diagnosis of types of hemophilia

A

Single factor assay using PTT and PT

47
Q

common to occur and
produces severe bleeding

A

Hemophilia A and B

47
Q

rare to occur and does not produce
severe bleeding

A

Hemophilia C

48
Q

is performed on patient’s diluted plasma, with 3-4
dilutions (1: 10; 1:20; 1:40; 1:80)

A

APTT

49
Q

The interval of the test is compared to the

A

laboratory’s
reference curve (percent activity