LESSON STRUCURE 

6.1 INTROCTION 

6.1 COLLECTION OF SAMPLE OTHER THAN BLOOD 

6.3 COLLECTION OF BLOOD SAMPLE 

6.4 PREPARATION OF THIN BLOOD FILM 

6.5 PREPARATION  OF THICK BLOOD FILMS 

6.6 QUESTION FOR EXERCISE 

                    6.3.2 COLLECTION OF BLOOD SAMPLE BY PRICK METHOD:

           
Blood is collected by prick method for making films on slides or for haemeoglobin estimation, total RBC and WBC count. For these purposes peripheral blood is obtained by pricking the finger tip or the ear or the heel in the case of infants with a sharp sterile needle. The puncture should we made vertically to a depth of 2-3mm so that a free flow of blood is obtained. The first few drops should be wiped away and then the sample is taken. Squeezing should be avoided. For estimation of Haemglobin, total RBC count and total WBC count special types of pipelts specially made for these purpose are used. A basic medical assistant need to know detail about these.

                     6.4  PREPARATION OF THIN BLOOD FILM:


         For making blood films slides are used. The slides used must be free from grease. After pricking the fingertip of ear lobule a drop of blood is taken on side, another slides is used for drawing the films. The slide with the blood drop is placed on a flat level surface. the narrow edge of the second slide is placed in the drop of blood and held there till the blood has spread across it. This slide is then held at an inclination of 45 degree with the first slide and then drawn slowly over the length of the first slide. there should be no pressure between the two surface. After  the blood is spread it should de dried by waving it rapidly in the air to prevent undue shrinkage of the cells. After the slide is dry it is ready for staining. However staining of sides is the job of Medical Laboratory technician, hence a basic medical assistant need not know detail about staining of slides. The blood film prepared by the procedure described above is a thin film. for dedication of parasites in blood the thin film as prepared above may be used after staining. But it is better to prepare a thick film for detection of parasites.

                      6.5 PREPARATION OF THIK FILM 

     The thick film method enables a much larger amount of blood to be examined than with thin films and is, therefore, valuable for the detection of parasites when these are present in small number.
       A drop of blood is taken on the centre of a slide and spread with a traingular needle until print can be clearly seen through it while it is still wet. The film is then allowed to dry by leaving it aside for about two hours, protected from dust.
       After the film is dry it is ready for being stained which again is the job of medical laboratory technician.
       as mentioned above the staining of thin or thick blood films is the job of medical laboratory technicians, hence the slides should be sent to pathological laboratory for examination. While sending the films, the name of the patient and a brief history of the case and provsional diagnosis made by the physician should be sent along with the slides.