Bleeding Time – Indications, Contraindications

Bleeding Time – Indications, Contraindications

Bleeding time is a clinical laboratory test performed to evaluate platelet function. It involves the creation of a standardized incision and timing the cessation of bleeding. The historical indications were the pre-operative assessment of patients taking aspirin or NSAIDs and screening for von-Willebrand disease. Unfortunately, it is insensitive and lacks reproducibility. Platelet function assay (i.e PFA 100) has largely replaced bleeding time. Despite the standardization of methods, the sensitivity and specificity of the bleeding time for platelet-mediated coagulopathy is low.

Many hospitals and health systems have removed the test without any demonstrated harm. In most cases, a thorough history and physical is the only workup needed for the pre-operative assessment of bleeding risk. When the clinical effectiveness of platelet aggregation is desired, a modern platelet function assay can provide the necessary information. This is being increasingly utilized in intracranial hemorrhage on various antiplatelet agents prior to pooled platelet transfusion.

Specimen Collection

While measuring the bleeding time requires trained personnel, no gross specimen collection is necessary. Modern alternative platelet function analyzers require a small aliquot of peripheral blood. Technicians utilize standardized instruments to perform and interpret the test.

Procedures

This test is performed via two primary methods based on the length and location of the incision.

The IVY method is the most common. The patient’s arm is positioned at the level of the heart, and a blood pressure cuff inflated to 40 mmHg. After cleansing with alcohol, a standardized device is utilized to make a 10mm long and 1mm deep incision on the volar forearm. Using a timer the blood is blotted twice a minute. The time stops when there is no further bleeding after blotting.

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The Duke method involves a stab incision in the patient’s cleaned finger or earlobe with a lancet. Otherwise, the methodology is the same.

The IVY method is more accurate but has an increased scarring risk. The Duke method is less accurate and carries a higher hematoma rate.

Either method carries the risks of infection and bleeding. In addition, the discomfort is not insignificant. Different normal ranges exist for each method further confounding the interpretation of results by lay clinicians.

Indications

The measurement of bleeding time is mostly of historical value in the screening of qualitative platelet abnormalities. It was used to screen for bleeding disorders and quantify platelet function in patients taking aspirin or non-steroidal anti-inflammatory medications. The American College of Clinical Pathologists position statement identifies a carefully conducted clinical history that includes family and previous dental, obstetric, surgical, traumatic injury, transfusion, and drug histories as the best predictor of bleeding risk. As most hospitals and laboratories have removed this exam from their offerings, it has fallen out of regular use. Most current uses are likely grounded in physician preference rather than clinical research.

Potential Diagnosis

  • Thrombocytopenia

    • Decreased platelet count impairs primary hemostasis. Sepsis, drug reactions, hematologic malignancies, autoimmune conditions, and vitamin deficiencies are among the non-inherited causes. Spontaneous bleeding is not generally a problem seen until counts fall beneath 30,000.
  • Von Willebrand Disease (vWD)

    • Von Willebrand disease is an inherited deficiency in the quantity or function of the platelet aggregation protein Von Willebrand factor. Rather than bleeding time,  modern workup includes complete blood count, factor VIII levels, ristocetin cofactor activity, and GP-Ib binding assay.
  • Disseminated Intravascular Coagulation (DIC)

    • DIC is a symptom of other severe disease processes like sepsis, burns, trauma, pregnancy, and malignancy. The coagulopathy is consumptive from the formation of blood clots throughout the peripheral vasculature. Thrombocytopenia with low fibrinogen and a high INR are the classic laboratory abnormalities.
  • Glanzmann’s

    • Glanzmann’s thrombasthenia is an autosomal recessive inherited defect in the fibrinogen binding receptor glycoprotein IIb/IIIa.
  • Bernard-Soulier Disease

    • Bernard-Soulier Syndrome is a rare autosomal recessive genetic defect in glycoprotein Ib causing giant platelets with perceived thrombocytopenia. Platelet transfusion is the treatment of choice.
  • Platelet Function Inhibiting Medications (aspirin, clopidogrel, ticagrelor, etc.)

    • Aspirin and other novel antiplatelet agents inhibit platelet aggregation and secretion overall inhibiting their function.

Normal and Critical Findings

Normal bleeding time:

  • Duke – Less than 3 minutes
  • IVY – Less than 8 minutes

Times greater than 5 minutes in the Duke method and 10 minutes in the IVY method are concerning for coagulopathy. Abnormalities would require further evaluation with a focus on the coagulation pathway of interest.

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References

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