Bleeding time measures the primary phase of hemostasis: the interaction of the platelet with the blood vessel wall and the formation of a hemostatic plug. Bleeding time is the best single screening test for platelet function disorders and is one of the primary screening tests for coagulation disorders.
This test is of value in detecting vascular abnormalities and platelet abnormalities or deficiencies. It is not recommended for routine presurgical workup.
A small stab wound is made in either the earlobe or the forearm; the bleeding time (the amount of time it takes to form a clot) is recorded. The duration of bleeding from a punctured capillary depends on the quantity and quality of platelets and the ability of the blood vessel wall to constrict.
The principal use of this test today is in the diagnosis of von Willebrand disease, an inherited defective molecule of factor VIII and a type of pseudohemophilia. It has been established that aspirin may cause abnormal bleeding in some normal persons, but the bleeding time test has not proved consistently valuable in identifying such persons.
310 minutes in most laboratories
Duke method (earlobe): 5 minutes (not recommended—not very reproducible with a wide range of normal values)
Ivy method (forearm with template): 28 minutes
Mielke method (Surgicut):
Adults: 17 minutes
Teens: 3.08 minutes
Children: 2.513 minutes
Clinical Alert
The critical value for bleeding time is >15 minutes.
If the puncture site is still bleeding after 15 minutes, discontinue the test and apply pressure to the site. Document and report the results to the healthcare provider.
Patients on heparin or Lovenox have a risk of heparin-induced thrombocytopenia with thrombosis syndrome (HITTS). Tests to diagnosis HITTS include IgG immune-mediated decrease and platelet count decrease. Stop heparin immediately when platelet count falls by 50%.
Procedure (Ivy Method)
Cleanse the area three finger widths below the antecubital space with alcohol and allow to dry.
Place a blood pressure cuff on the arm above the elbow and inflate to 40 mm Hg.
Select a cleansed area of the forearm without superficial veins. Stretch the skin laterally and tautly between the thumb and forefinger.
Start a stopwatch. Use the edge of a 4 × 4 inch filter paper to blot the blood through capillary action by gently touching the drop every 30 seconds. Do not disturb the wound itself. Remove the blood pressure gauge when bleeding stops and a clot has formed. Apply a sterile dressing when the test is completed.
The end point (by the Ivy or the earlobe method) is reached when blood is no longer blotted from the forearm puncture. Report in minutes and half minutes (e.g., 5 minutes, 30 seconds).
Bleeding time is prolonged when the level of platelets is decreased or when platelets are qualitatively abnormal:
Thrombocytopenia (platelet count <80 × 103/mm3)
Platelet dysfunction syndromes
Decrease or abnormality in plasma factors (e.g., von Willebrand factor, fibrinogen)
Abnormalities in the walls of the small blood vessels, vascular disease
End-stage kidney disease
Severe liver disease
Leukemia, other myeloproliferative diseases
Scurvy
DIC disease (owing to the presence of FDPs)
With von Willebrand disease, bleeding time can be variable; it will definitely be prolonged if aspirin is taken before testing (aspirin tolerance test).
A single prolonged bleeding time does not prove the existence of hemorrhagic disease. Because a larger vessel can be punctured, the puncture should be repeated on an alternate body site, and the two values obtained should be averaged.
Bleeding time is normal in the presence of coagulation disorders other than platelet dysfunction, vascular disease, or von Willebrand disease.
Aspirin therapy (antiplatelet function therapy): When thrombus formation is thought to be mediated by platelet activation, the patient frequently is given agents to interrupt normal platelet function, which may be monitored by bleeding times or platelet aggregation studies. Aspirin is the most commonly used inhibitor; it inhibits platelet adhesion or stickiness.
Pretest Patient Care
Explain test purpose and procedure. (See Patient Assessment for Bleeding Tendency.)
Instruct patient to abstain from aspirin and aspirin-like drugs for at least 7 days before the test.
Advise the patient to abstain from alcohol before the test.
Inform the patient that scar tissue may form at the puncture site (keloid formation).
If the patient has an infectious skin disease, postpone the test.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the need for possible follow-up testing and treatment. Monitor for prolonged bleeding. (See Patient Assessment for Bleeding Tendency.)
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Clinical Alert
Critical ValuesA decrease in platelets to <20 × 103/mm3 or <20 × 109/L is associated with a tendency for spontaneous bleeding, prolonged bleeding time, petechiae, and ecchymosis.
Platelet counts >50 × 103/mm3 or >50 × 109/L are not generally associated with spontaneous bleeding.
Normal values for bleeding time vary when the puncture site is not of uniform depth and width.
Touching the puncture site during this test will break off fibrin particles and prolong the bleeding time.
Excessive alcohol consumption (as in patients with alcohol use disorder) may cause increased bleeding time.
Prolonged bleeding time can reflect ingestion of 10 g of aspirin as long as 5 days before the test.
Other drugs that may cause increased bleeding times include dextran, streptokinasestreptodornase (fibrinolytic agents), mithramycin, and pantothenyl alcohol (see Appendix E).
Extreme hot or cold conditions can alter the results.
Edema of patients hands or cyanotic hands will invalidate the test.