Capillary fragility test

How the Test is Performed:
A tourniquet or blood pressure cuff is applied to the arm with enough pressure that the venous return of blood is prevented. The resulting increased capillary pressure may cause capillary rupture, which manifests as petechiae (small, purplish areas on the skin).

After 5 minutes, the pressure is released and the number of petechiae in a 2-inch area are counted and classified by a scoring system.

How to Prepare:
No special preparation is necessary for the capillary fragility test.

How it Feels:
There may be some discomfort from the pressure on your arm.

Risks:
If your capillaries are very fragile, bruising may result.

Why this Test is Performed:
Your health care provider may perform this test to generally evaluate the fragility of your capillary walls, or the deficiency of blood platelets ( thrombocytopenia ).

Normal Values:
The following scoring system is used to classify test results:
  • 0 to 10 petechiae : 1+
  • 11 to 20 petechiae: 2+
  • 21 to 50 petechiae: 3+
  • greater than 50 petechiae: 4+

A score of 1+ in the test area is considered normal.

Abnormal Results:
Test results of 2+ to 4+ are abnormal, indicating capillary weakness or platelet deficiency.

Disease that may result in capillary fragility include:



Cost:
This test may be performed as part of an office visit to your health care provider, and the fee will most likely be based on the length of time you are in the office. The cost of office calls varies from location to location.

Special Considerations:
Not applicable.