Calibrating centrifuges for Platelets Seperation
Each centrifuge should be calibrated upon receipt & after adjustment or repair .
1- collect from the donor an EDTA tube in addition to the specimen drawn for routine processing .
2- perform a platelet count on the EDTA specimen , if the donor has a platelet count below 133000/mm , this unit of blood shouldn’t be used for calibration .
3- Calculate the number of platelets in the unit of the whole blood (WB) .
Number of platelet in WB = platelet per mm x1000 x volume of WB
4- prepare platelet –rich plasma (PRP) at a selected speed & time .
5- place a temporary clamp on the tubing so that one satellite bag is closed off .
Express platelet rich plasma into the other satellite bag . Seal close to primary bag & disconnect the two satellite bags . Don’t remove the temporary clamp to the satellite bag until the next step .
6- Strip the tubing several times so the tubing contains a representative sample of platelet –rich plasma .
7-Seal off of the tubing & disconnect so the bag of platelet rich plasma remains sterile .
8- Perform a platelet count on the sample of platelet-rich plasma in the segment & calculate the number of platelets in the bag of platelet- rich plasma .
no. of platelets in PRP= platelets count/mm x1000xvolume of RPR .
9- Calculate % yield
% yield = no. of plt in RPR X100%
no. of plt in WB
10- Repeat the above process three or four times with different donors ,using different speeds & times of centrifugation .
11- Compare the yields for each set of centrifuge conditions .
12- Select the shortest time & lowest speed that result in the highest % yield of platelets in platelets rich plasma .
13- Centrifuge the platelets rich plasma at a selected time & speed to prepare platelets concentrate .
14- Express the platelets poor plasma into the second attatched satellite bag & seal the tubing , leaving along section of tubing attatched to platelets concentrate bag .
15- Place the platelets product on an agitator & leave at least for one hour to ensure that the platelets are evenly resuspended . platelets count cannot be performed accuretly on a product immediately after centrifugation .
16- strip the tubing several times , mixing its contents well with the contents of the platelets concentrate bag . let the concentrate flow back into the tubing . seal off a segment of the tubing so that the platelet concentrate bag remains sterile .
17- Perform a platelet count on the platelet concentrate . calculate the number of platelets in the platelets concentrate .
No. of plt in pc = pltcount /mm X 1000 X volume of pc
18- calculate % yield = no. of plt in pc X 100 %
no. of plt in prp
19- Repeat steps 13 through 18 using different speeds & times of centrifugation .
20 –Compare the yields for each set of centrifuge conditions .
21 – Select the shortest time & lowest speed that result in the highest % yield of platelets in the platelets concentrate .
Once each centrifuge has been calibrated , it is not necessary to recalibrate unless there is a problem with the mechanical function of the centrifuge .
بقلم
عادل عبد الحليم السلايمه
أخصائي طب مخبري
مسؤول جودة المياه / بلدية الخليل
السبت 29 نوفمبر - 8:15
