MLHP Review Questions for Quiz 3

Hemostasis

The process of stopping bleeding, which involves four systems: vascular spasm, platelet plug formation, coagulation, and fibrinolysis.

End Result of Hemostasis

The formation of a stable blood clot.

Primary Steps in Hemostasis

Vascular spasm and platelet plug formation.

Secondary Steps in Hemostasis

Coagulation and fibrinolysis.

Goal of Hemostasis

To prevent blood loss from damaged vessels.

Key Cell in Hemostasis

Platelet.

Final Product of Blood Clot Formation

Fibrin mesh that stabilizes the platelet plug.

Sequence of Clot Formation

1. Blood vessel injury 2. Vascular spasm 3. Platelet adhesion 4. Platelet aggregation 5. Coagulation cascade 6. Fibrin formation.

Fibrinolysis

The process of breaking down fibrin in blood clots.

Thrombus

A blood clot that forms within a blood vessel.

Embolus

A thrombus that has dislodged and traveled through the bloodstream.

Platelet Adhesion

The initial step where platelets stick to the damaged blood vessel wall.

Platelet Aggregation

The clumping together of platelets to form a plug.

Thrombocytopenia

A condition characterized by low platelet count.

Thrombocytosis

A condition characterized by high platelet count.

Coagulation Factors

There are 13 coagulation factors, named I (fibrinogen) to XIII.

Required Mineral for Coagulation

Calcium.

Different Pathways of Coagulation

Intrinsic, extrinsic, and common pathways.

Major Components of Fibrinolysis

Plasminogen and plasmin.

aPTT/PTT

Activated Partial Thromboplastin Time, measures the intrinsic pathway and monitors Heparin therapy.

PT (Prothrombin Time)

Measures the extrinsic pathway and monitors Warfarin therapy.

INR

International Normalized Ratio.

Laboratory Methods for Coagulation Testing

Coagulation assays such as PT, aPTT, and platelet counts.

Blood Collection Tube for Coagulation Testing

Light blue top tube containing sodium citrate.

Ratios for Anticoagulant in Coagulation Testing

9:1 ratio of blood to anticoagulant.

Number of Inversions for Coagulation Tube

Three inversions.

Clot Test Measurement Units

Seconds.

PT Specimen Testing Timeline

Test within 24 hours; can be stored for 48 hours at 2-8°C.

aPTT Testing Timeline

Test within 4 hours; stored at 2-8°C; samples for Heparin therapy should be run within 30 minutes.

Freezing Conditions for Platelet Poor Plasma

Frozen at -70°C for 6 months.

Additional Freezing Condition for Plasma

Frozen at -70°C for more than 6 months.

Type of Coagulation Sample Required for Analysis

Citrate plasma sample.

Factors Interfering with Clot Based Test Results

Contamination, improper anticoagulant ratio; solutions include correct collection technique and device calibration.

Problem if Solution is Adjusting Anticoagulant

Anticoagulant contamination.

Normal Range for INR, PT, aPTT

INR: 0.9-1.1, PT: 11-13.5 seconds, aPTT: 30-40 seconds.