1. Expose one upper limb adequately.
These steps are very important for those students who are preparing for USMLE and MRCP
2.Use adequate lighting.
3.Tie the sphygmomanometer ruff around the arm.
4.Mark out a circle of 3 cm diameter on the forearm about I
cm below the cubital fossa (where there are no petechiae).
5. Raise the cuff pressure to midway between systole and diastole.
6. Maintain pressure for 5 to 7 minutes.
7. Deflate the cuff and wait for 2 to 3 minutes (for congestion
to disappear).
8. Count the number of petechiae in the marked out area
Note
1.The diameter of an old one rupee coin is about 3
cms and it can be conveniently used to draw the circle
2. Normally, upto 10 petechlae can occur in the mentioned area.
More than 20 arc definitely abnormal. Note that petechiac can vary in size from
pin point to pin head or larger.
3.. The tourniquet test is positive in most cases of
thrombocytopenia and in increased capillary fragility. It is anessential part
of examination in any patient with bleeding disorder.
These steps are very important for those students who are preparing for USMLE and MRCP
