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 

                              6.1 INTRODUCTION 

        In principle of medical it has always been said that diagnosis should precede treatment. The doctor, when he examines a patient, he makes a diagnosis on the basis of history, physical and clinical examination in most of the cases. however, in certain cases he has to get certain pathological investigation done to confirm his provisional diagnosis or to clinic a diagnosis. 

          For pathological investigations sample have to be collected from the patient. This may be sample of blood  or some other material or specimen from the patient. When a patient is being examined by the doctor in his clinic as an outdoor patient he is sent to a pathology lab. For collection there. But if the patient is admitted to a nursing home the sample have to the collected there. Hence a basic medical assistant must know to collect and send sample to a pathology lab. 


                                  6.2  COLLECTION OF SAMPLE OTHER THAN BLOOD



        It is essential that all sample or specimens collected should read the laboratory fresh and correctly collected in the correct kind of containers. Suitable containers are best obtained from the laboratory that is going to make the investigation. All containers must be perfectly clean and preterbably sterile, this is important for specimen for bacteriological investigation. The name of the patient and nature of specimen should be written on a piece of paper and pasted on the container.

             Specimen or sample are best taken to the laboratory as soon as possible after they are obtained, perfectly by hand. In case the specimen are to be sent outside the town where they are collected, it should be carefully packed. Such specimen must be placed in a sealed inner container and then packed in a wooden or metal box containing sufficient absorbent material to soak up liquid content if the inner container is per chance broken. If they ere to be sent by post they should be labelled 'Fragile' 'with care' and 'Pathological Specimen' All local and international regulation about the transmission of Pathological material must be strictly adhered to.

   

                  6.3  COLLECTION OF BLOOD SAMPLE 

            Blood sample for most investigation are collected in vials after obtaining blood by VENEPUNTURE, but for some investigations the samples may be collected by 'Prick method'


              6.3.1 COLLECTION OF BLOOD SAMPLE BY VENEPUNCTURE;


           Containers for blood sample should be completely dry. All containers must have properly fitting lids or caps. It is essential that the correct container should be used for each particular investigation because particular anticoagulants are necessary for each particular chemical or other tests of blood. It is also desirable that the amount of material specified for a particular container should be placed in that container.

         For VENEPUNCTURE all syringe and needle must be sterile. It is preferable to use the disposable variety. The steps for VENEPUNCTURE are the same as those detailed for intraveneous injection till the needle has been introduced into the vein, the needle being directed in the direction of the blood flow. With the tourniquet in place the required amount of blood is withdrawn in the syringe and then the tourniquet is removed before the needle is withdrawn. As soon as the needle is withdrawn a swab soaked in spirit is placed on the puncture site and the patient is instructed to hold his forearm firmly fixed against the arm for a minute or so. Sometimes a vein in the forearm firmly flexed against the arm for a minute or so. Sometimes a vein in  the forearm or wrist may prove more convinient than one at the elbow, put the procedure then is usually painful for the patient. 

          Blood obtained by VENEPUNCTURE should be placed immidiately in a container appropriate for the purpose for which sample has been collected. The needle should be first removed from the syringe, since forcing blood through the needle may cause haemolysis. Appropriate containers for particular investigation should be obtained from the laboratory. From blood grouping and serological investigation blood should be written on a small piece of paper and pasted on the container or tube in all cases.