HEMA312 MIDTERMS - Lesson #4: Laboratory Evaluation of Fibrinolysis

In Whole Blood Clot Lysis Time, a clot is dissolved as a result of_______

plasmin activity

Normally, the dissolving of clot in WBCLT does not occur in _________ because of the presence of plasmin inhibitors

less than 72 hours

What is the normal value of Whole Blood Clot Lysis Time?

Lysis of Clot After 24 Hours

What is the principle behind whole blood clot lysis time?

A clot is dissolved as a result of plasmin activity. Normally, this does not occur in less than 72 hours because of the presence of plasma inhibitors which inactivate plasmin as it forms.

In this method of laboratory evaluation for fibrinolysis, a whole blood is diluted with a buffer solution

Diluted Blood Clot Lysis Time

What is the main principle behind DBCLT?

Plasmin inhibitors loose activity on dilution.

In Diluted Blood Clot Lysis Time, what is the reagent used to clot the blood?

Thrombin

In DBCLT What do you do after putting thrombin?

The clot is recorded and observed for lysis

What is the normal value/reference range for DBCLT?

Blood clot should not lyse in less than 6-10 hours.

A method of laboratory evaluation where blood is collected in an anticoagulant, centrifuged and then the plasma is recalcified.

Plasma Clot Lysis Time

In Plasma Clot Lysis time, what happens after when you recalcify the plasma?

The plasma forms clot

Incubation temperature for the resultant plasma clot in plasma clot lysis time

37°C

For how long will you observe lysis of the plasma clot in plasma clot lysis time?

over 48 hours

A screening procedure that measures the overall fibrinolytic activity

Euglobulin Clot Lysis Time

TRUE OR FALSE

Euglobulin Clot Lysis Time is the most specific clot lysis time test performed

TRUE

What is the euglobulin fraction of plasma in Euglobulin Clot lysis time?

1. Plasminogen

2. Plasminogen Activator

3. Fibrinogen

An Increased Fibrinolytic Activity in the screening procedure for overall fibrinolytic activity is/are associated with?

1. Circulatory Collapse

2. Adrenal Injection

3. Pulmonary Surgery

4. Pyrogen Reaction

5. Sudden Death

6. Obstetric Reaction

7. Extreme Stress

(CAPPSOE)

In the screening procedure for measurement of overall fibrinolytic activity, this is the reagent added that is responsible for the lysis of a fibrin clot

Thrombin

A procedure used to detect the presence of fibrin monomers.

Protamine Sulfate Turbidity Test

Protamine Sulfate Turbidity Test is a specific and sensitive blood test used as a confirmatory test for diagnosing the presence of what disease/s?

1. Venous thromboembolic disease

2. Disseminated Intravascular Coagulation

Presence of Fibrin Monomers in the clot is associated with what disease/s?

1. Pulmonary Embolism

2. Liver Cirrhosis

A procedure that measures a specific fragment from the degradation of a cross-linked fibrin.

Latex D-Dimer Assay

The test which measures measures a specific fragment from the degradation of a cross-linked fibrin is specific for?

Cross-linked D-dimer fragment of fibrin

The test which measures measures a specific fragment from the degradation of a cross-linked fibrin is positive for what disease?

Early Disseminiated Intravascular Coagulation (DIC)

TRUE OR FALSE

FDP assay is superior in sensitivity and specificity compared to the Latex D-dimer Assay

FALSE

Specimen of choice for Latex D-Dimer Assay

Fresh Citrated/Heparinized/EDTA plasma specimen (as well as serum).

TRUE OR FALSE

Serum has a higher content of D-Dimer than plasma.

FALSE

2 methods of assay employed in Latex D-Dimer Assay

1. Enzyme immunoassay

2. Latex bead

Reference Range for Latex D-Dimer Assay

Less than 200 ng/mL should be present

A type of assay used in Latex D-Dimer which is low and sensitive

Enzyme Immunoasay

A type of assay used in Latex D-Dimer which is a rapid simple semi-quantitative assay

Latex Bead

What are the associated disease/s with a positive Latex D-Dimer Assay

1. DIC

2. Pulmonary and cerebral embolism

3. Phlebitis

4. Thrombosis

5. Sickle cell disease

In patients suffering from DIC, patients also have this condition, wherein there are presence of unwanted clots within their vessels.

Deep Vein Thrombosis

The methods of assay for Quantitative assay of Fibrin-Fibrinogen Degradation Products are based on:

1. Red Cell hemagglutination

2. Staphylococcal agglutination

3. Immunodiffusion

What is the negative result for Quantitative assay of Fibrin-Fibrinogen Degradation Products?

No Agglutination

What is the positive result for Quantitative assay of Fibrin-Fibrinogen Degradation Products?

Agglutination

What is the normal result for Quantitative Assay of Fibrin-Fibrinogen Degradation Products?

A. Presence of Agglutination

B. No Agglutination

B.

Reagent used in Tanned Red Cell Hemagglutination Inhibition Immunoassay?

Tannic Acid

This is present in the patient's serum, which neutralizes antifibrinogen, antiserum, thereby preventing the antiserum from agglutinating fibrinogen-coated erythrocytes.

Fibrin Degradation Product (FDPs)

What is the normal result for Tanned Red Cell Hemagglutination Inhibition Immunoassay?

A. Presence of Agglutination

B. No Agglutination

A.

In tanned red cell hemagglutination inhibition immunoassay, if there is a presence of FDP, what will be the reaction?

A. Presence of Agglutination

B. No Agglutination

B.

Inactivates thrombin and other serine proteases

Antithrombin

What is the role of heparin in plasma antithrombin test?

hastens the inactivation of thrombin by promoting the action of Antithrombin

If antithrombin levels are low, what is the consequence?

A person will have a tendecy to clot blood more easily

If antithrombin levels are high, what is the consequence?

Bleeidng Tendency of a person

A type of Antithrombin deficiency where antithrombin functions normally but is produced insufficiently

Type 1 Antithrombin Deficiency

A type of Antithrombin Deficiency where antithrombin is produced sufficiently but is dysfunctional

Type 2 antithrombin deficiency

TRUE OR FALSE

Increased Antithrombin Levels are not usually considered a problem.

TRUE

A test the measures the availability of functional fibrinogen.

Plasma Thrombin Time

A sensitive test in detecting heparin inhibition.

Plasma Thrombin Time

What is the principle of plasma thrombin time?

A measured amount of thrombin is added to plasma. The length of time for a fibrin clot to form is recorded as thrombin time.

Prolonged Thrombin Time is associated with what condition/s?

1. Hypofibrinogenemia / Afibrinogenemia (decreased fibrinogen levels)

2. Dysfibrinogenemia - abnormal Fibrinogen Function

3. Disseminated Intravascular Coagulation

Specimen of Choice for Plasma Thrombin Time

Citrated Plasma stored at 2-8°C

Abnormal fibrinolysis impair fibrin formation and can also conditionWhens such as

1. end stage liver disease

2. malnutrition.

Whenever thrombin is used, what type of glassware/pipettes should be used?

Plastic or Siliconized Glassware

series of tests used to detect lupus anticoagulant (LA) in the blood.

Tissue Inhibition Test (Assay for Lupus Anticoagulant)

It is an autoantibody associated with excess blood clot formation.

Lupus Anticoagulant

Lupus anticoagulant testing may be used to determine the cause of:

1. Unexplained blood clot (thrombosis) in vein or artery

2. Help investigate the cause of a blood clot (thrombotic episode)

3. To evaluate a prolonged partial thromboplastin time.

4. To help determine the cause of recurrent miscarriagesL

5. As part of an evaluation for antiphospholipid syndrome

TRUE OR FALSE

Lupus anticoagulant assay is used to diagnose Systemicn Lupus Erythematosus

FALSE

Method used in Assay for Lupus Anticoagulant

Schleider’s method

When do you perform Diluted Russel Viper Venon Test?

When clotting time is prolonged

Once the dRVVT test is calculated and the ratio is less than the cutoff, what should you do next?

Report dRVVT as negative for Lupus Anticoagulant (LA)

Once the dRVVT test is calculated and the ratio is greater than or equal to the cutoff, what should you do next?

Check if the patient has a concurrent warfarin therapy.

In dRVVT, if the patient exceeds the ratio or cutoff of the normal values for dRVVT test but without concurrent warfarin therapy, what is the implication?

dRVVT is positive; positive for lupus anticoagulant

In dRVVT, if the patient exceeds the ratio or cutoff of the normal values for dRVVT test and with concurrent warfarin therapy, what should be done?

Perform a mixing study and rrepeat algorithm with mixed plasma sample.