تويت
Bleeding Time tests
Bleeding Time Duke
A standardized incision is make in the ear lobe and the blood is blotted with filter paper every 30 seconds until it stops flowing. Vessel integrity and platelets are measured.
A. Rough evaluation of platelet function
B. Procedure-
1. Cleanse ear lobe
2. Make a 2-4mm cut with disposable lancet
3. Blood is blotted every 30 seconds using the edge of filter paper, being careful not to disturb the clot as it forms
4. Time is recorded when bleeding has ceased
5. Reference range: 1-3 minutes
6. When an abnormal value is obtained, the test should be performed on the other ear.
Bleeding Time Ivy
A blood pressure cuff is placed on the upper arm and maintained at 40 mm of mercury. A standardized incision is made on the volar surface of the forearm and the blood is blotted with filter paper every 30 seconds until it stops flowing. Vessel integrity and platelets are measured.
A. Procedure-
1. Blood pressure cuff is placed on arm and inflated to 40mm Hg
2. With pressure maintained, the arm is cleaned and a lancet is again used to make a 2-4 mm cut on the volar aspect of the forearm, being careful NOT to cut any visible blood vessels.
3. Filter paper is used to blot blood as described above.
4. Reference range: 3-9 minutes
5. Advantages of Procedure:
a. Easier with children
b. More reproducible than Duke method
Interpretation/Theory of Bleeding Time:
A. Abnormal Results could be due to:
1. Thrombocytopenia, with failure to produce a platelet plug
2. Poor platelet function
3. Failure of vessel constriction on injury
4. Puncture of larger blood vessel (technical error)
5. Blood pressure cuff too tight or too loose (technical error)
6. Disturbing the clot (technical error)
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