Bleeding time (Ivy method)

Principle

• A standard small skin incision is made under constant venous pressure, and the time for bleeding to stop is measured.
• It tests primary haemostasis: platelet number and function, von Willebrand factor and the vessel wall.

Specimen

• Performed on the patient; no sample tube. Ask about aspirin or NSAID use; aspirin should ideally be stopped about 7–10 days before.

Reagents and equipment

• Sphygmomanometer cuff, disposable spring-loaded template device (standard incision about 5 mm long and 1 mm deep), filter paper, stopwatch, antiseptic.

Procedure

• Place the cuff on the upper arm and inflate to 40 mm Hg; keep constant throughout.
• Clean the volar forearm, avoiding visible veins, scars and bruises.
• Make the incision with the device and start the stopwatch.
• Every 30 s blot the blood with filter paper, without touching the wound edges.
• Stop timing when blood no longer stains the paper; release the cuff and apply a butterfly strip.

Results

• Typical upper limit with template devices is about 8–10 min; each lab must establish its own range.

Interpretation

• Prolonged: thrombocytopenia (usually below about 50–100 × 10^9/L), platelet function disorders (Glanzmann thrombasthenia, Bernard–Soulier syndrome, storage pool disease), von Willebrand disease, aspirin and NSAIDs, uraemia, scurvy and some vascular disorders.
• Usually normal in haemophilia A and B and other coagulation factor deficiencies.

Quality control and pitfalls

• Poorly reproducible and operator dependent; affected by skin thickness, temperature, incision depth and site.
• Touching the wound dislodges the platelet plug and falsely prolongs the time.
• May leave a small scar; risk of keloid in susceptible patients.
• Does not predict surgical bleeding reliably; largely replaced by PFA-100/200 and platelet aggregation studies.

Clinical use

• Historical screen for primary haemostatic defects when other tests are unavailable.