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Platelet Count 12

الكلية كلية طب الاسنان     القسم  العلوم الاساسية     المرحلة 2
أستاذ المادة وسن نجم عبد السادة الربيعي       22/02/2019 23:55:51
Platelet Count
Platelets (Thrombocytes) are a nucleated, disc-shape, have a diameter about 1-3 µ, generally ovoid in shape but with wide variation. In blood film they are blue staining with red granules throughout the cytoplasm (Fig.1).
Platelets are released into the circulation to prevent leakage or bleeding caused by inherent or acquired defect in blood vessel walls. The cells have life span of about one week.
There are about 250000 platelets per cubic millimeter. Platelets can easily be counted in special counting chamber. Venous blood is a better source than capillary blood for the platelet count. It has been shown that platelet counts from capillary blood may underestimate the venous blood count significantly; therefore, venous blood should be used if an accurate platelet count is essential. Since finger prick may cause clumping of platelets.

DILUTING FLUID:
The blood is diluted in 1% ammonium oxalate which hemolyses the blood cells ( dissolve 1 gm of ammonium oxalate in 100 ml of distilled water).

Procedure:
1.Take 0.02 ml (20 ?L) of blood by using haemoglobin pipette .
2.Add the blood after having wiped the tip of pipette to 0.38 ml of diluting fluid.
3.Charge the chamber with the help of a pasteur pipette.
4.Place the counting chamber in a Petri dish counting a moistened filter paper and let stand for 15 min.
5.Count under the high power objective lenses with light partially cut off (reduced condenser) in the same squares as indicated for RBC counting.


Cells counted × blood dilution × Depth factor
Platelets count =
Area of chamber counted


Platelets count= N × 1000
(Platelet/mm3)

N: Platelet counted in 5 square.


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .