Bleeding time
The bleeding time is a medical test with the help of which disorders of the primary hemostasis , i.e. the hemostasis , can be detected.
execution
Bleeding time is the time it takes for bleeding to stop. There are various methods of doing this.
Ivy method
The Ivy bleeding time in the Mielke modification is a frequently used method. First, a blood pressure cuff is attached to the patient's upper arm and set to 40 mmHg (5.32 kPa ) pressure so that the pressure conditions in the tissue are standardized. In the next step, a small incision with a defined length and depth is made in a favorable location on the forearm. Without touching the wound, the outflowing blood is removed with a sterile swab (or paper towel) every 30 seconds. As soon as the reddening is no longer detectable on the swab, the bleeding time is considered complete.
The reference time is 4 to 6 minutes.
Duke's method
Here a lancet prick is placed on the edge of the earlobe and, as with the Ivy method, the blood is removed with cellulose or paper every 15 seconds.
The reference time is 3 to 5 minutes.
Bleeding time according to Marx
This method involves putting a lancet prick in the fingertip . Immediately afterwards, the finger is immersed in a water-filled flask glass (at 37 ° C). The time to visual bleeding arrest is then measured.
The reference time is up to 2 minutes.
Diagnostic significance
In the case of minor injuries, the thrombus formed by the blood platelets stops the bleeding. Therefore, the bleeding time is mainly determined by the number and function of platelets.
The bleeding time is therefore prolonged in the case of thrombocytopenia (diseases which result in a reduced number (<100 / nl) of blood platelets) and thrombocytopathies (blood platelets that do not work properly). This can also be prolonged in the case of Willebrand-Jürgens syndrome and the use of substances that inhibit aggregation.
Other possible causes for an altered bleeding time are dysproteinemia , uremia and severe hypo- to afibrinogenemia .
The bleeding time is often carried out as a screening test for organ punctures, although it has not been proven to what extent this value is informative about any complications that may occur.
In veterinary medicine , the mucosal bleeding time is determined for the same purpose .
literature
- Klaus Dörner: Clinical Chemistry and Hematology . Enke Verlag, ISBN 3-432-97313-6 .
Web links
Individual evidence
- ↑ Archive link ( Memento of the original from October 23, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ http://www.laborlexikon.de/Lexikon/Infoframe/b/Blutungszeit.htm
