Bleeding Time Test
Sample Type: Whole Blood
Specimen Collection: Capillary blood via skin puncture (usually fingertip or earlobe) or venous blood in specific testing situations.

Overview
Bleeding time is a clinical test used to evaluate platelet function and the ability of blood vessels to constrict and form a hemostatic plug after injury. It measures how long it takes for bleeding to stop following a standardized skin puncture. This test helps assess primary hemostasis—the first step in stopping bleeding, involving vascular contraction and platelet plug formation.

Purpose
The bleeding time test is primarily used to:

Evaluate platelet disorders (e.g., thrombocytopathy)

Monitor vascular integrity

Investigate unexplained prolonged bleeding

Assess preoperative bleeding risk

Help diagnose von Willebrand disease

Evaluate the effect of antiplatelet medications like aspirin

Procedure
There are two common methods:

Ivy Method (more commonly used):

A blood pressure cuff is inflated on the upper arm to 40 mmHg.

A standardized incision is made on the forearm.

The time from the puncture until bleeding stops is measured by blotting blood at 30-second intervals.

Duke Method (less commonly used):

A fingertip or earlobe is pricked with a lancet.

Blotting is done every 30 seconds to assess when bleeding stops.

Normal bleeding time:

Ivy method: 2–9 minutes

Duke method: 1–4 minutes
(Times may vary slightly depending on the technique and lab standards.)

Interpretation
Prolonged Bleeding Time May Indicate:
Platelet dysfunction (qualitative defects)

Thrombocytopenia (low platelet count)

von Willebrand disease

Use of aspirin or other NSAIDs

Uremia (in chronic kidney disease)

Liver disease

Normal Bleeding Time With Bleeding Symptoms:
May suggest coagulation factor deficiencies rather than platelet issues

Limitations
The test is not highly specific or sensitive.

Results can be affected by skin thickness, environmental conditions, and operator technique.

It has largely been replaced by more accurate and reproducible tests like:

Platelet function analyzer (PFA-100/200)

Platelet aggregation studies

Clinical Significance
Though now considered outdated in many modern laboratories, bleeding time may still be used in settings with limited access to advanced platelet function testing. It offers a quick, bedside assessment of primary hemostasis and helps inform surgical risk in certain patients.

Conclusion
The bleeding time test evaluates the functional integrity of platelets and small blood vessels. While no longer widely used due to variability and the availability of better alternatives, it remains a historically significant tool in the understanding of hemostasis and is still utilized in specific clinical scenarios.