I am going to explain a test which I had the oppotunity to view for myself during my placement at Haematology Laboratory.
Bleeding Time using Surgicutt
This test is to estimate the integrity of the hemostatic plug. It is a screening test for
qualitative and quantitative platelet functions and generally helps to diagnose hemostatic defects and platelet dysfunctions.
Principle
When a minor standardized incision is made on the forearm, time between the infliction of the incision and the moment the bleeding stops is taken. A hemostatic plug is formed after the incision to stop the bleeding. This plug formation depends on adequate platelets to adhere to the subendothelium to form aggregates.
For this test is a screening test, an increased bleeding time would not qualitatively or quantatively diagnose an underlying platelet disorders. However, it is indicative of the need for more quantifiable testing such as platelet counts, APPT, TT testing etc.
Image of Surgicutt Bleeding device taken from http://www.medcompare.com/
Procedure
1. First, a sphygmomanometer is used to cuff the upper hand of the patient. The pressure is raised to 40 mm Hg.This is the standard pressure for children and adults. For infants, the pressure would be dependant on the weight. Patient’s blood pressure was to remain at such throughout the duration of the test.
2. The volar surface of the forearm, where the incision is to be made, is rubbed with alcohol swab.
3. The incision is made using Surgicutt bleeding time device and the timer is started simultaneously. There are three different devices to suit different age group, mainly infants, children and adults. This is shown below.
Age group :1 - 4 months
Device:Surgicutt Newborn
Depth of blade (mm) :0.50
Age Group:5 months to 15 yrs
Device: Surgicutt Junior
Depth of blade (mm): 1.00
Age Group: 16 years and above
Device: Surgicutt
Depth of blade(mm): 1.00
4. Every 30 seconds, a blotting paper was used to wick the blood close to the incision without touching the incision itself.
5. The timer is stopped when the bleeding stopped.
6. Reading on timer is recorded down.
The following are the reference values for normal bleeding time:
Infants (1-4 months) :
0.85- 1.65 mins
Children (5 months to 15 years) :
1.3- 8.99 mins
Adults (16 years and above) :
2-8 mins
For neonates whose bleeding does not stop after 5 minutes, time is reported as >5 mins. For adults whose bleeding does not stop for more than 20 minutes, time is reported as >20 mins.
Raihana~
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6 comments:
hi rai, may i know what is TT test? does it stand for thrombin clotting time or does it stand for something else?
elyana
0606676e
yes u are right, it stands for thrombin time =D
hi rai,
u mentioned that for infants, the pressure would b dependant on the weight. So the heavier the infant, the higher the pressure to be applied? Is there like a formula to calculate around how much pressure should be applied?
Secondly, for 5mths to 15yrs, surgicutt junior is used and for 16yrs and above, surgicutt is used. However, the depth of blade for both is 1mm, so what is the difference between surgicutt and surgicutt junior? thanks.
Malerie
TG02
For the newborns, is it also done on the arm? Because from what i noticed, the arms of neonates are really thin. And is the bleeding time test done for premature babies? I heard that due to the size of babies, the loss of blood which is insignificant to adults actually are of significance to them.
-cornelyus
hey rai,
you mentioned that the patient’s blood pressure need to remain constant throughout the duration of the test, may i know how can the blood pressure affect the bleeding time?
thanks
Liyanah Zaffre
0607718D
TG02
answers to questions
to malerie:
the bloo pressure to be adjusted for infants is as follows:
for babies: <1kg= 20mmHg
1-2kg+ 25mm Hg
>2kg= 30mm Hg
im glad u brought that up. it reminds me that i had forgotten to include that the diffference between Surgicutt for Adult and Surgicutt Junior lies within the width of the blade. for surgicutt adults, the width of the blade is for Surgicutt Junior, it is 3.5mm.
to cornelyus:
the incision is made on teh volar surface of teh arm, not the main veins, so it is stil possible to carry out this test. for premature babies, this test can be carried out for them but it is rare.
to liyanah:
the blood presure must be kept constant because blood pressure affects teh blood flow right.
for example, if someone is experienceing high blood pressure and is taking the test without using teh sphygmamonometer, his blood pressure would be high and the results would not be accurate.
i hope i had answered all ur queries =)
raihana~
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