Bleeding Time

Bleeding time (BZ) is the time that elapses after artificial placement of a bleeding injury until hemostasis (“hemostasis”) occurs. It is a test for the orientational assessment of primary hemostasis.

Procedures

Duke bleeding time: placing a lancet puncture at the edge of the earlobe.Without touching the wound, the blood that flows out is removed every 15 seconds with cellulose or a sterile swab. Once no redness is detectable on the swab, the bleeding time is considered complete.

Bleeding time according to Ivy: For this purpose, 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 of defined length and depth is made at a convenient location on the inside of the forearm.Without touching the wound, any blood that leaks out is removed every 30 seconds using cellulose or a sterile swab. As soon as no more redness can be detected on the swab, the bleeding time is considered complete.Subaqueous bleeding time according to Marx: For this purpose, a lancet puncture is placed in the fingertip. Immediately afterwards, the finger is immersed in a flask filled with water (at 37° C). The time to visual bleeding arrest is then measured.

Normal values

Procedure Standard values
Bleeding time according to Duke 3-5 min.
Bleeding time according to Ivy – 5 min.
Subaqueous bleeding time according to Marx – 2 min.

Indications

Interpretation

Prolongs bleeding time

  • Hemorrhagic diathesis (pathologically increased bleeding tendency).
  • Thrombopathies (dysfunction of platelets (blood clots)).
  • Thrombocytopenias (deficiency of platelets (blood platelets) in the blood): Platelets < 100/nl
  • Willebrand-Jürgens syndrome – most common congenital blood clotting disorder in humans.
  • Other disorders:
    • Dysproteinemias (disturbance of the protein balance in the blood).
    • Uremia (occurrence of urinary substances in the blood above normal values).
    • Severe hypo- to afibrinogenemia
  • Medications:
    • Acetylsalicylic acid (ASA)
    • Platelet aggregation inhibitors (drugs that inhibit the clumping of platelets (platelet aggregation)).
    • Heparin in high doses
    • Non-steroidal anti-inflammatory drugs (NSAIDs)

Caveat: A severely prolonged bleeding time is indicative of a threatening or life-threatening bleeding tendency and requires immediate further evaluation.

Further indications

  • In cases of exclusively plasmatic coagulation disorders, a normal BM is usually present!