Bleeding time

Bleeding time

Bleeding time is a medical test done on someone to assess their platelet function.

It involves cutting the underside of the subject's forearm, in an area where there is no hair or visible veins. The cut is of a standardised width and depth, and is done quickly by an automatic device.

A blood pressure cuff is used above the wound, to maintain venous pressure at a special value. The time it takes for bleeding to stop (as thus the time it takes for a platelet plug to form) is measured. Cessation of bleeding can be determined by blotting away the blood every several seconds until the site looks 'glassy'.

Bleeding time is affected by platelet function, certain vascular disorders and von Willebrand Disease--not by other coagulation factors such as haemophilia. Diseases that cause prolonged bleeding time include thrombocytopenia and disseminated intravascular coagulation (DIC).

Aspirin and other cyclooxygenase inhibitors can prolong bleeding time significantly. While warfarin and heparin have their major effects on coagulation factors, an increased bleeding time is sometimes seen with use of these medications as well.

People with von Willebrand disease usually experience increased bleeding time, as von Willebrand factor is a platelet agglutination protein, but this is not considered an effective diagnostic test for this condition.

Normal values fall between 2 - 9 minutes depending on the method used.

Ivy method

The Ivy method is the traditional format for this test. In the Ivy method, a blood pressure cuff is placed on the upper arm and inflated to 40 mmHg. A lancet or scalpel blade is used to make a stab wound on the underside of the forearm.

A standard-sized cut is made (usually using an automatic blade.) The time from when the stab wound is made until all bleeding has stopped is measured and is called the bleeding time. Every 30 seconds, filter paper or a paper towel is used to draw off the blood.

The test is finished when bleeding has stopped completely.

External links

[http://www.nlm.nih.gov/medlineplus/ency/article/003656.htm MedlinePlus Medical Encyclopedia]


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • bleeding time — n a period of time of usu. about two and a half minutes during which a small wound (as a pinprick) continues to bleed * * * the duration of bleeding that follows puncture of the skin; see bleeding time test, under test …   Medical dictionary

  • bleeding time — noun The time it takes for bleeding to stop in a bleeding time test …   Wiktionary

  • bleeding time test — a test of bleeding time, assessing capillary function and platelet function, such as Duke t., Ivy t., or the template method …   Medical dictionary

  • bleeding time — noun : a period of time of usually about 2 1/2 minutes during which a small wound (as a pinprick) continues to shed blood …   Useful english dictionary

  • bleeding time test — noun A test used to assess the ability of a persons blood to clot, carried out by cutting the skin and measuring the time it takes for the resulting bleeding to stop …   Wiktionary

  • time — 1. That relation of events which is expressed by the terms past, present, and future, and measured by units such as minutes, hours, days, months, or years. 2. A certain period during which something definite or determined is done. SYN: tempus (2) …   Medical dictionary

  • Bleeding Through — performs at Alpine Valley Music Theatre as part of the Ozzfest in 2006 Background information …   Wikipedia

  • Bleeding Kansas — Part of Prelude to American Civil War Date 1854 to 1860 Location Kansas and Missouri Result …   Wikipedia

  • Bleeding Love — Single par Leona Lewis extrait de l’album Spirit Leona Lewis interprétant Bleeding Love durant le concert de La …   Wikipédia en Français

  • Bleeding Love — Saltar a navegación, búsqueda «Bleeding love» Sencillo de Leona Lewis del álbum Spirit Lado B «Forgiveness» Publicación 19 de octubre de 2007 …   Wikipedia Español

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”