Do some patients with arthritis or connective tissue disease have a Biphasic APTT?

Dr  F Hall, Dr Luddington, Mrs Furlong,

The APTT (activated partial thromboplastin time) is a clotting test, which is measured from a routine blood test. This test is usually performed either to find out if a patient has an abnormality in their blood clotting system or to monitor treatment with the “blood-thinning” agent, heparin.

It has been discovered that the APTT test sometimes displays a “blip” in the course of the clotting. This has become known as a “biphasic APTT”. A study of patients on intensive care units showed that the presence of a biphasic APTT predicted the development of a abnormal clotting condition, in which uncontrolled clotting and bleeding occur at the same time.

Recently, a patient with rheumatoid arthritis in Addenbrooke’s hospital was found to have a biphasic APTT. This individual had active arthritis but was otherwise well. They did not show any signs of the abnormal clotting/bleeding disorder, described above, which is predicted by the biphasic APTT in intensive care patients.

The purpose of this study is to:

1. To assess whether a biphasic APTT occurs in patients with inflammatory arthritis or vasculitis (inflammation of blood vessel walls).
2. If a biphasic APTT does occur in some arthritis patients, whether its presence correlates with the activity of inflammatory disease.

Terms & Conditions © 2005 Cambridge Arthritis Research Endeavour - Registered Charity No. 802862 © 2005 Design & Programming :Biscuit Software Ltd