Related Experiment Video

Updated: Apr 27, 2026

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time
09:38

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time

Published on: February 14, 2017

16.3K

Coagulation

Y L Chee1

  • 1YL Chee Consultant Haematologist Department of Haematology-Oncology NUHS Tower Block Level 7 1E Kent Ridge Road Singapore 119228 e-mail yen_lin_chee@nuhs.edu.sg.

The Journal of the Royal College of Physicians of Edinburgh
|July 5, 2014
PubMed

The haemostatic system comprises four compartments: the vasculature, platelets, coagulation factors, and the fibrinolytic system. There is presently no laboratory or near-patient test capable of reproducing the complex regulated interaction between these four compartments. The prothrombin time (PT) and activated partial thromboplastin time (APTT) only test the coagulation protein compartment of the system and results have to be carefully interpreted in the context of the clinical presentation and assay limitations. This article will give a general overview of the limitations of PT and APTT and discuss specific issues that need to be considered when the tests are requested, in the context of anticoagulant monitoring, bleeding symptoms, and routine preoperative screening. Of these indications, routine preoperative screening is the most controversial and is generally not warranted in the absence of an abnormal bleeding history.

Keywords:
Prothrombin timeactivated partial thromboplastin timebleeding historycoagulation screenpreoperative screeningthrombin clotting time

More Related Videos

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo06:23

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo

Published on: August 4, 2018

8.0K
Author Spotlight: Deciphering Coagulation Disorders in Traumatic Brain Injury Patients04:56

Author Spotlight: Deciphering Coagulation Disorders in Traumatic Brain Injury Patients

Published on: August 4, 2023

1.4K

Related Concept Videos

Coagulation01:09

Coagulation

The coagulation phase is a critical part of the body's process to prevent blood loss following injury to blood vessels. It involves chemical reactions that form a clot to seal the injured area. The clotting process begins shortly after injury, within 15-20 seconds for severe damage and 1-2 minutes for minor injuries.
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
8.3K
Coagulation01:06

Coagulation

Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
1.5K
Extrinsic and Intrinsic Pathways of Hemostasis01:20

Extrinsic and Intrinsic Pathways of Hemostasis

Blood clotting or coagulation involves extrinsic and intrinsic pathways, which ultimately merge into the common pathway, forming a fibrin clot.
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
10.8K
Introduction to Hemostasis01:05

Introduction to Hemostasis

Hemostasis is a complex physiological process that prevents excessive bleeding when a blood vessel is injured. It's crucial for maintaining the integrity of the circulatory system, as it ensures that our blood remains fluid while still within the vascular network and yet clots to prevent blood loss upon vessel injury.
The three phases of hemostasis involve many clotting factors present in plasma and several substances released by platelets and injured tissue cells. It is a fast, localized,...
14.0K
Anticoagulant Drugs: Low-Molecular-Weight Heparins01:30

Anticoagulant Drugs: Low-Molecular-Weight Heparins

Hemostasis is a crucial process that prevents excessive blood loss from damaged blood vessels. It involves various mechanisms such as vasoconstriction, platelet adhesion and activation, and fibrin formation. The importance of each mechanism depends on the type of vessel injury. In contrast, thrombosis is the abnormal formation of a blood clot within the blood vessels, leading to potential complications if the clot obstructs blood flow. Thrombosis can be caused by increased coagulability of the...
2.6K
Clot Retraction and Fibrinolysis01:16

Clot Retraction and Fibrinolysis

After a fibrin clot is formed, the next step is clot retraction, a vital process facilitated by platelet contractile proteins, such as actin and myosin. These proteins pull the fibrin strands closer together and condense the clot. This action reduces the size of the clot, creating a smaller, denser structure that effectively seals off the damaged vessel. Clot retraction consolidates the clot and helps with wound healing by bringing the edges of the damaged blood vessel closer together.
6.0K