Bleeding time is a

medical test A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic te ...

done on someone to assess their

platelet Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

s function. It involves making a patient bleed, then timing how long it takes for them to stop bleeding using a

stopwatch A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock. ...

or other suitable devices. The term template bleeding time is used when the test is performed to standardized parameters.

Indications

The bleeding time test is a method indicated when other more reliable and less invasive tests for determining

coagulation Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism o ...

are not available., which cites #* #* #* However, it remains the most reliable way of assessing clinical bleeding in patients with

uremia Uremia is the term for high levels of urea in the blood. Urea is one of the primary components of urine. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be no ...

. Historically it was indicated whenever physicians needed information about platelet activation.

Process

It involves cutting the underside of the subject's forearm, in an area where there is no hair or visible

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

s. The cut is of a standardized 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 specified value. The time it takes for the bleeding to stop (i.e. the time it takes for a

platelet plug The platelet plug, also known as the hemostatic plug or platelet thrombus, is an aggregation of platelets formed during early stages of hemostasis in response to one or more injuries to blood vessel walls. After platelets are recruited and begi ...

to form) is measured. Cessation of bleeding can be determined by blotting away the blood every several seconds until the site looks "glassy".

IVY method

The IVY method is the traditional format for this test. While both the IVY and Duke's method require the use of a

sphygmomanometer A sphygmomanometer ( ), a blood pressure monitor, or blood pressure gauge, is a device used to measure blood pressure, composed of an inflatable cuff to collapse and then release the artery under the cuff in a controlled manner, and a mercury (e ...

, or blood pressure cuff, the IVY method is more invasive than the Duke method, utilizing an incision on the ventral side of the forearm, whereas the Duke method involves puncture with a lancet or special needle. In the IVY method, the blood pressure cuff is placed on the upper arm and inflated to 40 mmHg. A lancet or scalpel blade is used to make a shallow incision that is 1 millimeter deep on the underside of the forearm. A standard-sized incision is made around 10 mm long and 1 mm deep. The time from when the incision 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. A prolonged bleeding time may be a result from decreased number of thrombocytes or impaired blood vessels. However, the depth of the puncture or incision may be the source of error. Normal values fall between 3 – 10 minutes depending on the method used. A disadvantage of Ivy's method is closure of puncture wound before stoppage of bleeding.

Duke's method

With the Duke's method, the patient is pricked with a special needle or lancet, preferably on the

earlobe The human earlobe (''lobulus auriculae''), the lower portion of the outer ear, is composed of tough areolar and adipose connective tissues, lacking the firmness and elasticity of the rest of the auricle (the external structure of the ear). In ...

fingertip A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...

, after having been swabbed with alcohol. The prick is about 3–4 mm deep. The patient then wipes the blood every 30 seconds with a filter paper. The test ceases when bleeding ceases. The usual time is about 2–5 minutes. This method is not recommended and cannot be standardized because it can cause a large local hematoma.

Interpretation

Bleeding time is affected by platelet function, certain vascular disorders and

von Willebrand Disease Von Willebrand disease (VWD) is the most common hereditary blood-clotting disorder in humans. An acquired form can sometimes result from other medical conditions. It arises from a deficiency in the quality or quantity of von Willebrand factor ( ...

—not by other

factors such as

haemophilia Haemophilia, or hemophilia (), is a mostly inherited genetic disorder that impairs the body's ability to make blood clots, a process needed to stop bleeding. This results in people bleeding for a longer time after an injury, easy bruising, ...

. Diseases that cause prolonged bleeding time include

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients an ...

, disseminated intravascular coagulation (DIC), Bernard-Soulier disease, and

Glanzmann's thrombasthenia Glanzmann's thrombasthenia is an abnormality of the platelets. It is an extremely rare coagulopathy (bleeding disorder due to a blood abnormality), in which the platelets contain defective or low levels of glycoprotein IIb/IIIa (GpIIb/IIIa), which ...

Aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...

and other

cyclooxygenase Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as prosta ...

inhibitors can significantly prolong bleeding time. While

warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent strok ...

and

heparin Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the treatm ...

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 Von Willebrand disease (VWD) is the most common hereditary blood-clotting disorder in humans. An acquired form can sometimes result from other medical conditions. It arises from a deficiency in the quality or quantity of von Willebrand factor ( ...

usually experience increased bleeding time, as

von Willebrand factor Von Willebrand factor (VWF) () is a blood glycoprotein involved in hemostasis, specifically, platelet adhesion. It is deficient and/or defective in von Willebrand disease and is involved in many other diseases, including thrombotic thrombocytopen ...

is a platelet adhesion protein, but this is not considered an effective diagnostic test for this condition. It is also prolonged in

hypofibrinogenemia Factor I deficiency, also known as fibrinogen deficiency, is a rare inherited bleeding disorder related to fibrinogen function in the blood coagulation cascade. It is typically subclassified into four distinct fibrinogen disorders: afibrinogenem ...

In popular culture

In the British comedy film ''

Doctor in the House ''Doctor in the House'' is a 1954 British comedy film directed by Ralph Thomas and produced by Betty Box. The screenplay, by Nicholas Phipps, Richard Gordon and Ronald Wilkinson, is based on the 1952 novel by Gordon, and follows a group of st ...

'' (1954), Sir Lancelot Spratt, the intimidating chief of surgery played by

James Robertson Justice James Robertson Justice (15 June 1907 – 2 July 1975) was a British actor. He is best remembered for portraying pompous authority figures in comedies including each of the seven films in the '' Doctor'' series. He also co-starred with Greg ...

is asking instructional questions of his medical students. He asks a young student, who has been distracted by a pretty nurse, what "the bleeding time" is. The student looks at his watch and answers "Ten past ten, sir."

References

External links

MedlinePlus Medical Encyclopedia
{{DEFAULTSORT:Bleeding Time Blood tests