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Hematology > Hema Lec #8: Mixing Studies > Flashcards

Hema Lec #8: Mixing Studies Flashcards

1
Q

Identify the specific coagulation factor

deficient in the px’s abnormal plasma

A

Factor identification tests

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2
Q

Studies that Determines what specific coagulation factor is
deficient/missing in the plasma that is responsible for the
abnormal coagulation tests results

A

Mixing Studies

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3
Q

Other name for mixing studies

A
  • Factor identification tests
  • Substitution tests/studies
  • PT and aPTT substitution tests
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4
Q

more common to cause defect

in px’s plasma

A

Lupus anticoagulant

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5
Q

What is the main usefulness of mixing studies

A

To differentiate a factor deficiency from the presence

of a circulating inhibitor/circulating anticoagulant

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6
Q

-Plasma different healthy patients combined
together in one container
- Ready to substitute whatever missing coag
factor in px plasma when mixed

A

Normal Pooled Plasma

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7
Q

2 Types of Mixing Studies

A

Immediate Mixing Study

Incubated Mixing Study

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8
Q

Reagents Used for Mixing Studies

A 
Normal Pooled Plasma
Adsorbed Plasma (AP)

Aged Serum (AS

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9
Q

-Portion of the pooled plasma
-Removes the Vitamin K Dependent Coagulation
Factors/Prothrombin Group in the normal plasma

A

Adsorbed Plasma (AP)

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10
Q

Different reagents are responsible for adsorbing the

normal pooled plasma. What are those reagents?

A

-Barium Sulfate Adsorbed
Plasma
-Aluminum Hydroxide
Adsorbed Plasma

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11
Q

A portion of that volume is placed in another

container then incubated at 37°C for 3 days

A

Aged Serum

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12
Q

Aged serum replinish what factors?

A

VII, IX, X, XI, & XII

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13
Q

Adsorbed Plasma replinish what factors

A

(factors V, VIII, XI, and XII)

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14
Q

Main usefulness of thrombin time

A

to measure the availability of functional

fibrinogen

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15
Q

Main usefulness of reptilase time

A

measures the availability of

functional fibrinogen

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16
Q
  • Low fibrinogen levels (<200 mg/dL)

- Fibrinogen normal reference range: 200-400 mg/dL

A

Hypofibrinogenemia

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17
Q

No fibrinogen in plasma

- TT is definitely prolonged

A

Afibrinogenemia

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18
Q

Normal levels, but dysfunctional fibrinogen

A

Dysfibrinogenemia

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19
Q

Principle for Factor VIII Screening Test

A

stabilization of the fibrin clot depends on plasma

factor XIII

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20
Q

First stage of mixing studies

A

extract information/identify

cause of the prolonged coagulation test

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21
Q
  • Interferes with coagulation reactions
  • Prolongs phospholipid-dependent tests such as APTT and
    occasionally PT
A

Lupus-like Anticoagulant

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22
Q

3 Steps in LLAC Identification

A
  1. Demonstration of an abnormality of
    phospholipid-dependent coagulation reactions
  2. Routine mixing studies
  3. Reducing or adding an excess of phospholipid to the test
    system
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23
Q
  • Directly activates the common pathway without
    activating the extrinsic pathway
  • Evaluates deficiencies in the common pathway
  • Also contains a reduced amount of phospholipids
    and calcium chloride
A

Dilute Russell’s Viper Venom Time

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24
Q

-More sensitive screening test for APA
- Can also evaluate the intrinsic & common
pathway and heparin anticoagulant therapy
- Similar to the APTT procedure, but does not
supply phospholipids as a reagent

A

Kaolin Clotting Time (KCT)

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25
Q

negatively charged substance that will

activate contact factor in the px’s plasma

A

Kaolin

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26
Q
  • Confirmatory test for the presence of lupus
    anticoagulant (together with platelet neutralization
    procedure)
  • Modification of PT
A

Tissue Thromboplastin Inhibition Test (TTI)/Dilute Tissue

Thromboplastin Inhibition test (dTTI)

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27
Q
  • Termed as Thromboplastin Calcium Chloride reagent
  • Has inhibitory effect to the antiphospholipid antibody
  • Concentrated thromboplastin reagent of PT test has
    inhibitory action to APA
A

Prothrombin time reagent

28
Q

T/F.PT does not detect lupus anticoagulant

A

TRUE

29
Q
  • Confirmatory test with excess phospholipids in the test

system

A

Platelet Neutralization Procedure

30
Q

Source of excess phospholipids in Platelet Neutralization Procedure

A

freeze-thawed

platelets/ruptured platelets

31
Q

T/F. TT does not measure defects in the intrinsic and extrinsic pathway

A

True

32
Q

Normal value for the TT to occur

A

10-16 seconds approximately 15 seconds

33
Q

It inhibits the thrombin reagent

A

Antithrombin III-Heparin Complex

34
Q

A thrombin-like enzyme that only cleaves alpha fibrinopeptinde chain in E domain

A

Reptilase time

35
Q

Test that measure fibrin formation that cleaves both alpha and bets fibrinopeptide chains

A

Thrombin time

36
Q

What enzyme is present in reptilase time

Asa ni sha makit.an

A

Serine protease enzyme

Venom of Bothrops atrox snake

37
Q

What test that used to differentiate dysfibrinogenia and presence of fibrin degradation product/ heparin

A

Reptilase enzyme

38
Q

TT: prolonged

Reptilase time: more/severely prolonged

A

Dysfribrinogenemia

39
Q

TT: prolonged

Reptilase time: Normal

A

Presence of Heparin

40
Q

TT: more/severely prolonged

Reptilase time: prolonged

A

Presence of FDP

41
Q

Why does the reptilase time in the presence of FDP is prolonged?

A

Because FDP has an inhibitory effect to reptilase

42
Q

What does the behavior of FDP in the context of TT

A

Behave as anti-thrombin therefore inhibits thrombin reagent

43
Q

What contamination causing reptilase time normal and prolonged TT

Cite remedy to this contamination

A

Heparin contamination

Running Reptilase Test in Parallel

44
Q

In running reptilase test in parallel remedy, what other remedy is used when reptilase time is unavailable

A

Rerun thrombin time, add protamine sulfate before thrombin = inhibits heparin

45
Q

Principle for factor XIII screening test

A

Stabilization of the fibrin clot depends on plasma factor XIII

46
Q

what specimen is used in thrombin time?

A

citrated-platelet poor plasma

47
Q

it measures the availability of functional fibrinogen but it only cleaves the alpha fibrinopeptide chain in E-domain

A

Reptilase time

48
Q

What rtype of snake is used during measuring the availability of funcitonal fibrinogen? its chsracteriestic ss also a serine protease enzyme

A

bothrops antrox snake

49
Q

A method that used to confirm heparin contamination as the cause of prolonged TT

A

Reptilase Time

50
Q

What cause when TT is prolonged while reptilase time is severely proloned

A

dysfibrinogenemia

51
Q

What caused when TT is prolonged but reptilase time is normal

A

presence of heparin

52
Q

What caused when TT is severely prolonged and reptilase time is also prolonged.

A

Presence of FDP

53
Q

Addition of reptilase to CPPP initiates clot formation. CLot formation may be detected by what method?

A

electromechanical method

54
Q

what is being added when reptilase time is unavailable?

A

protamine sulfate

55
Q

In what way does Factor XIII stabilize the fibrin clot

A

by converting hydrogen bonds to covalent bonds by transamination

56
Q

T/F. in the absence of Factor XIII, the covalent bond fibrin polymers are soluble in 5m urea or 1% monochloroacetic acid.

A

False. Hydrogen Bond

57
Q

What reagent is used in Dilute Russell’s Viper Venom Time

A

stypven reagent

58
Q

T/F. DRVVT ealuates deficiencies in the common pathway and extrinsic pathway

A

False. only in common pathway

59
Q

T/F. Stypven Time is a thromboplastin-like substance that impersonates the behavior of the tissue thus, it activates extrinsic pathway only

A

False. directly activates common pathway without activaitng the extrinsic pathway

60
Q

Which of the following does not relate to dilute russell’s viper venom time?

a. evaluates deficiencies in the common pathway such as fibrinogen, prothrombin, factor V and factor X
b. when stypven rgt is added, Factor X is immediately activated
c. contians a reduced amount of phospholipids and calcium chloride
d. does not supply phospholipid as a rgt
e. none of the above

A

d. does not supply phospholipdi as a rgt

61
Q

A screening test similar to APTT procedure but does not supply phospholipids as a reagnet

A

Kaolin Clotting Time

62
Q

Which of the followign is false about Kaolin Clotting Time

a. more sensitive screening for APA
b. evaluate only intrinsic and heparin anticoagulant therapy
c. similar to APTT procedure, but does not supply phospholipids as a rgt
d. kaolin relies only on the normal plasma phospholipids of the patient

A

b. evaluate only intrinsic and heparin anticoagulant therapy

63
Q

A test that reduce or add an excess of phospholipid to the test

A

Platelet Neutralization test

64
Q

Which of the following is true about Tissue Thromboplasitn Inhibition test

I. confirmatory test for the presence of lupus anticoagulant
II. modification of PT
III. confirmatory test with excess phospholipids in the test systems
IV. does not add excess phospholipids

a. I, II, III, IV
b. I, II, IV
c. I, II, III
d. I and IV only

A

I, II, IV

65
Q

What is the source of excess phospholipids in platelet neutralization procedure

A

freeze-thawed platelets or ruptured platelets

66
Q

What is the result of aPTT after the confirmatory test with excess phosphilipids is being done? Explain.

A

normal. because APA were all inhibited by the excess phospholipids added to the test systems

Hematology (18 decks)

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