Tourniquet test

Tourniquet Test

The tourniquet test is a clinical diagnostic tool used to assess capillary fragility and the tendency to bleed. It is often employed in the evaluation of patients suspected of having dengue fever or other conditions that affect the vascular system.

Procedure

The tourniquet test involves the application of a blood pressure cuff to the upper arm, inflated to a point between the systolic and diastolic blood pressures, and maintained for a specified period, usually five minutes. After the cuff is released, the forearm is examined for the appearance of petechiae, which are small red or purple spots caused by bleeding into the skin.

Interpretation

A positive tourniquet test is indicated by the presence of more than 20 petechiae per square inch on the forearm. This result suggests increased capillary fragility and may be indicative of conditions such as dengue fever, thrombocytopenia, or other bleeding disorders.

Clinical Significance

The tourniquet test is particularly useful in the diagnosis of dengue fever, where it is one of the criteria used by the World Health Organization (WHO) for clinical diagnosis. A positive test can help differentiate dengue from other febrile illnesses, especially in endemic areas.

Limitations

While the tourniquet test is a useful diagnostic tool, it is not specific to any one disease and should be used in conjunction with other clinical findings and laboratory tests. False positives can occur, and the test may not be reliable in patients with pre-existing skin conditions or those on medications that affect bleeding.

Related Pages

• Dengue fever
• Petechiae
• Thrombocytopenia

References

• World Health Organization. "Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control." WHO, 2009.
• Gubler, D. J. "Dengue and Dengue Hemorrhagic Fever." Clinical Microbiology Reviews, 1998.

Images

A positive tourniquet test showing petechiae on the forearm.