Coagulation System (Part II) Flashcards by Gay Amor Tipolo Gacang

Must be tested within 24 hours of the time of collection

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Must be tested within 4 hours of the time of
collection

APTT

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PT reagents (or thromboplastin, tissue thromboplastin) consists of:

tissue factor
phospholipids
calcium chloride.

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It is most sensitive to factor VII deficiencies

Prothrombin Time (PT)

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Is used most often to monitor the e ects of
therapy with Coumadin

Prothrombin Time (PT)

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Prolonged PT results in:

• DIC
• Liver disease
• Vitamin K deficienc

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

Partial Thromboplastin Time (APTT)

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

Partial Thromboplastin Time (APTT)

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PTT Negatively charged particulate activator

kaolin, ellagic acid, silica, or celite

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PTT Is prolonged when there is a deficiency of one or more of the following coagulation factors:

• II, V, VIII, IX, X, XI, XII
• I (if <100 mg/dL)

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Most common deficiencies of PTT

• Factor VIII (Hemophilia A)
• Factor IX (Hemophilia B)
• Factor XI (Rosenthal syndrome)

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Distinguish LACs from specific inhibitors and factor deficiencies

PTT Mixing Studies

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In PTT Mixing Studies UFH may be neutralized with

polybrene or heparinase

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

Thrombin Clotting Time

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Is used to determine whether UFH is present
whenever the PTT is prolonged

Thrombin Clotting Time

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May also assess the presence of the oral direct
thrombin inhibitor dabigatran.

+ drug = markedly prolonged

Thrombin Clotting Time

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provides quantitative measure of dabigatran

Plasma-diluted TCT

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Reptilase is a thrombin-like enzyme isolated from the venom of

Bothrops atrox (lancehead viper)

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Venom Activated Assays:

Cleaves fibrinopeptide A only

Reptilase Time

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Venom Activated Assays:

Useful for detecting hypofibrinogenemia or
dysfibrinogenemia

Reptilase Time

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Russell Viper Venom (RVV) from the

Daboia russelii viper

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Venom Activated Assays:

triggers coagulation at the level of factor X

Russell Viper Venom Test

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List the Coagulation Factor Assays

Fibrinogen Assay
Single-Factor Assays using the PTT
Nijmegen-Bethesda Assay
Single-Factor Assays using the PT
Factor XIII Assay

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Clot-based method of Clauss

Fibrinogen Assay

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• A modification of TCT •Is the recommended procedure for estimating fibrinogen function

Fibrinogen Assay

Reagents of Fibrinogen Assay

• Owren buer • Bovine thrombin

Explain what happened in Single-Factor Assay using the PTT

● Factor VIII-depleted PPP (alone): ➡️ prolonged PTT ● Factor VIII-depleted PPP + Normal patient plasma: ➡️ PTT reverts to normal ● Factor VIII-depleted PPP + Factor VIII-deficient patient plasma: ➡️prolonged

Confirms and quantifies anti-factor VIII inhibitor (typically IgG4-class immunoglobulin)

Nijmegen-Bethesda Assay

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

is defined as any single or multiple coagulation factor or platelet deficiency

Coagulopathy

Accounts for most instances of fatal hemorrhage

Trauma-Induced Coagulopathy

Resembles the pathophysiology of TTP

Trauma-Induced Coagulopathy

TIC Management

✅ Plasma ✅ FP-24 ✅ VWF and Factors V and VIII activities decline to approximately 60% after 5 days of refrigerator storage

the key TIC management component

Plasma

alters the production of the Vitamin K-dependent factors

Liver Disease Coagulopathy: Procoagulant deficiency

In Liver Disease Coagulopathy: Procoagulant deficiency this serves as the sensitive early marker

Factor VII

In Liver Disease Coagulopathy: Procoagulant deficiency this is a more specific marker of liver disease

Factor V

During Dysfibrinogenemia, the fibrin is coated with excessive

sialic acid

Treatment to Resolve Liver Disease-Related Hemorrhage

1. Oral or intravenous vitamin K therapy 2. Plasma transfusion

Is often associated with platelet dysfunction and mild to moderate mucocutaneous bleeding (anemia and thrombocytopenia)

Chronic Renal Failure and Hemorrhage

In Chronic Renal Failure and Hemorrhage this coat the platelets

Guanidinosuccinic acid or phenolic compounds

is a state of increased glomerular permeability associated with a variety of conditions

Nephrotic syndrome

In Nephrotic syndrome, what are detected in the urine

factors II, VII, IX, X, XII, antithrombin, protein C

Vitamin K Antagonists

Warfarin (Coumadin) Coumadin overdose: PIVKA factors

disrupts the vitamin K epoxide reductase and vitamin K quinone reductase reactions

Warfarin (Coumadin)

the single most common reason for hemorrhage-associated emergency department visits

Coumadin overdose

the most common acquired autoantibodies

Autoanti-factor VIII

Factor Inhibitors other than Autoanti-factor VIII

1. Antiprothrombin antibodies 2. Autoanti-factor XIII 3. Autoantibodies to factor V 4. Autoanti-factor X

Factor Inhibitors other than Autoanti-factor VIII Develop as lupus anticoagulant

Antiprothrombin antibodies

Factor Inhibitors other than Autoanti-factor VIII Documented in patients receiving isoniazid treatment for tuberculosis

Autoanti-factor XIII

Factor Inhibitors other than Autoanti-factor VIII May arise spontaneously in autoimmune disorders and after exposure to bovine thrombin in fibrin glue

Autoantibodies to factor V

Factor Inhibitors other than Autoanti-factor VIII In amyloidosis

Autoanti-factor X

The most prevalent inherited mucocutaneous bleeding disorder

von Willebrand Disease

Leads to decreased platelet adhesion to injure vessel walls

von Willebrand Disease

Describe the 3 domains in vWF

Domain A: supports the receptor site for collagen and GP Ib/IX/V Domain C: provides a site that binds GP IIb/IIIA Domain D: provides the carrier site for factor VIII

● Caused by autosomal dominant frameshifts, nonsense mutations, or deletions ● Comprises 40-70% of vWD cases

Type 1 von Willebrand Disease

Arises from an autosomal dominant point mutations in A2 and D1 structural domains of the vWF molecule

Subtype 2A

VWF is susceptible to ADAMTS-13

Subtype 2A

Mutations within the A1 domain

Subtype 2B

Raised anity to GP Ib/IX/V

Subtype 2B

"gain-of-function" mutation

Subtype 2B

A platelet mutation that raises GP Ib anity for normal HMW-VWF multimers

Platelet-type vWD (PT-VWD) or pseudo-VWD under Subtype 2B

Possesses poor platelet receptor binding despite generating a normal multimeric distribution pattern in electrophoresis

Subtype 2M

Missense mutation in the D9 domain impairs the protein's factor VIII binding site

Subtype 2N

Factor VIII deficiency despite a normal VWF antigen concentration assay result, normal VWF activity, and a normal multimeric pattern

Subtype 2N

Subtype 2N is also known as

Autosomal Hemophilia

"Null allele" VWF gene translation or deletion mutations

Type 3 von Willebrand Disease

Is the most rare form of VWD

Type 3 von Willebrand Disease

Von Willebrand Disease Treatment

PRICE (protection, rest, ice, compression, elevation)

Also called Christmas disease

Hemophilia B

Also called Rosenthal syndrome, Factor XI deficiency

Hemophilia C

More than half of the cases have been described in Ashkenazi Jews

Hemophilia C

an eective form of therapy of Factor V Deficiency

Platelet concentrate