Alternative names: capillary fragility test, Hess test, Rumpel-Leede test
Method:
(1) Mark a circle on the forearm. This is often 1 inch (2.5 cm) in diameter but some use a larger circle.
(2) Mark any pre-existing skin lesions.
(3) Inflate a sphyngmomanometer about the upper arm to a pressure midway between the systolic and diastolic blood pressures.
(4) Leave the cuff inflated for several minutes, then deflate it. The time of pressure application varies, and may range from 5, 10 or 15 minutes.
(5) The patient should not be left unattended during the test. If a large number of petechiae appear, then the test may need to be terminated early.
(6) Wait a few minutes to allow all petechiae to appear. Count the number of petechiae within the test area.
Interpretation:
• Most patients will form no or rare petechiae.
• The cutoff for a positive test varies on a number of factors, such as the desired sensitivity and specificity, the duration that pressure is applied, and the size of the test area.
• Some use >= 5 petechiae after a 5 minutes application period, while others use >= 10 petechiae for a 15 minute application period.
• Alternatively the number on the forearm and hand can be graded as follows:
|
Number of Petechiae
|
Grade
|
|
none or rare
|
0
|
|
few
|
1+
|
|
some
|
2+
|
|
many
|
3+
|
|
very large number
|
4+
|
Limitations:
• The test has significant variability, with a large number of variables that are hard to control. The test may be useless if done incorrectly.
• Different areas of the arm may show different number of petechiae. If only 1 area is examined then the fragility may be over or underestimated. It is probably reasonable to count several areas and average the number.
• An arm can only be used every 1 or 2 weeks.
