MedlinePlus Medical Encyclopedia: Bleeding time

Skip navigation


Medical Encyclopedia
Other encyclopedia topics:	A-Ag Ah-Ap Aq-Az B-Bk Bl-Bz C-Cg Ch-Co Cp-Cz D-Di Dj-Dz E-Ep Eq-Ez F G H-Hf Hg-Hz I-In Io-Iz J K L-Ln Lo-Lz M-Mf Mg-Mz N O P-Pl Pm-Pz Q R S-Sh Si-Sp Sq-Sz T-Tn To-Tz U V W X Y Z 0-9

Bleeding time

Contents of this page:
Illustrations Definition How the test is performed How to prepare for the test How the test will feel	Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations

Illustrations

Blood clot test

Definition Return to top

This is a test that measures the speed in which small blood vessels close off to stop bleeding (the condition of the blood vessels) and platelet function.

How the test is performed Return to top

A blood pressure cuff is placed on the upper arm and inflated. Two incisions are made on the lower arm. These are about 10 mm (less than 1/2 inch) long and 1 mm deep (just deep enough to cause minimal bleeding). The blood pressure cuff is immediately deflated. Blotting paper is touched to the cuts every 30 seconds until the bleeding stops. The length of time it takes for the cuts to stop bleeding is recorded.

How to prepare for the test Return to top

Certain medications can interfere with platelet function and therefore may alter test results. Always make sure to tell your doctor what medications you are taking, even over-the-counter preparations. Your health care provider may ask you to discontinue these medications several days prior to the test. Never discontinue medication without consulting your health care provider.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

Infant test or procedure preparation (birth to 1 year)
Toddler test or procedure preparation (1 to 3 years)
Preschooler test or procedure preparation (3 to 6 years)
Schoolage test or procedure preparation (6 to 12 years)
Adolescent test or procedure preparation (12 to 18 years)

How the test will feel Return to top

The incisions are very shallow and should feel like scratches.

Why the test is performed Return to top

This test is useful for detecting bleeding tendencies.

Normal Values Return to top

The bleeding stops within 1 to 9 minutes. This may vary from lab to lab, depending on how the test is measured.

What abnormal results mean Return to top

Prolonged bleeding time may indicate:

A vascular (blood vessel) defect
A platelet function defect (see platelet aggregation)
Thrombocytopenia (low platelets)

Drugs that may increase bleeding times include dextran, indomethacin, and salicylates (including aspirin).

Additional conditions under which the test may be performed:

What the risks are Return to top

There is a very slight risk of infection where the skin is broken. Excessive bleeding is rare.

Special considerations Return to top

The bleeding time test is used to evaluate the vascular (blood vessel) and platelet factors associated with hemostasis (blood clot formation). When vascular injury occurs, the first hemostatic response is a spastic contraction of the lacerated vessels. Next, platelets adhere to the wall of the vessel at the area of laceration in an attempt to plug the hole. The failure of either process results in a prolonged bleeding time.

Update Date: 5/7/2003

Updated by: Marcia S. Brose, M.D., Ph.D., Division of Hematology/Oncology, Hospital of the University of Pennsylvania, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.