Clinical Chemistry I 0202304 PDF

Clinical Chemistry I 0202304 Instructor: Mohammad QABAJAH E-mail: [email protected] Week 02 Specimen Collection and Processing 2 Objectives I. Describe the steps in the proper acquisition (Patient preparation, specimen preservation...

Clinical Chemistry I 0202304 Instructor: Mohammad QABAJAH E-mail: [email protected] Week 02 Specimen Collection and Processing 2 Objectives I. Describe the steps in the proper acquisition (Patient preparation, specimen preservation, timing of collection and specimen handling) II. Summarize and discuss the aspects of specimen handling in relation to specimen identification on various containers. III. Describe the skin puncture collection technique IV. Discuss order of draw for multiple blood specimens, including the order required for collecting multiple tubes of blood Definitions - Additives Compounds added to biological specimens to prevent them from clotting or to preserve the constituents of a specimen - Anticoagulant Substance that prevents blood from clotting - Chorionic villus sampling A prenatal test to detect birth defects that is performed at an early stage of pregnancy and involves retrieval and examination of tissue from the chorionic villi - Coagulation (clotting) The sequential process by which the multiple coagulation factors of blood interact in the coagulation cascade to form insoluble fibrin clot Definitions - Diurnal variation Variation that occurs in the amount of a substance during a 24-hour period. - Hemolysis Disruption of the red cell membrane causing release of hemoglobin and other components of red blood cells - Phlebotomy The puncture of a blood vessel to collect blood; literally, “the letting of blood in the treatment of disease.” - Preanalytical errors Factors that affect specimens before tests are performed and that can lead to error if not controlled; they are classified as controllable or uncontrollable. Definitions - Preservative A substance or preparation added to a specimen to prevent changes in the constituents of a specimen. - Plasma The noncellular component of anticoagulated whole blood; plasma contains clotting factors. - Serum The watery portion of blood that remains after coagulation has occurred; it is obtained after centrifugation. - Sharps container a container designed for the disposal of sharps Definitions - Skin puncture Collection of capillary blood usually from a pediatric patient by making a thin cut in the skin, usually at the heel of the foot. - Specimen A sample or portion of body fluid or tissue collected for analysis. - Venipuncture All of the steps involved in obtaining an appropriate and identified blood specimen from an individual’s vein. - Venous occlusion Obstruction of the return of venous blood to the heart and distention of the veins; in phlebotomy, this is a temporary blockage caused by application of pressure, usually from a tourniquet. Critical Specimen Issues Specimen should be valid: Appropriate policies, procedures and techniques for: ̵ Collection ̵ Identification ̵ Processing ̵ Storage ̵ Transport Errors here are called: Pre Analytical errors Controllable Types of Specimens ̵ Whole blood ̵ Serum ̵ Plasma ̵ Urine ̵ Feces ̵ Saliva ̵ Spinal, synovial, amniotic, pleural, pericardial, and ascitic fluids ̵ Solid tissue ̵ Cells Blood Phlebotomy: The puncturing of a vein or the surgical opening of a vein to draw blood - Veins: - Specimen of choice for most analyte - Venipuncture; venous blood - Arteries: - Mainly for blood gas analyses - Arterial puncture; arterial blood - Capillaries. - Young children, point-of-care tests - Skin puncture; capillary blood Equipment I- Syringes: Needles; Butterfly infusion set (Scalp Vein) II- Evacuated System: Tubes and Needle Holder To the vein / Enter first Collecting tube Venipuncture - Patient should be seated or supine for as long as possible - Not standing at all - Torniquet is applied - Causes occlusion - No longer than 1 minute - Cause changes in chemical composition Venipuncture The collecting tubes Contain additives such as: - Anticoagulant - Preservatives Denoted by a stopper color Skin Puncture - Skin punctured using lacnet - Blood collected into - Microdevice - Direct to testing device - Sample volume is small - Pediatric applications - Repeated venipunctures have resulted in severe vein damage - Patients have been burned or bandaged - Point-of-care testing Skin Puncture Site of puncture: ̵ The tip of a finger ̵ Earlobe ̵ Heel or big toe of infants Arterial Puncture: Mainly for gas analysis (pO2, pCO2, pH) Performed by: ̵ Physicians ̵ Specially trained technicians or nurses Sites of arterial puncture: ̵ Radial artery at the wrist ̵ Brachial artery in the elbow ̵ Femoral artery in the groin See YOU Next Lecture ☺