Introduction-to-Hematology.pdf

Introduction to Hematology Raquel M. Fernandez, RMT, MSPH What is Hematology?  The study of blood.  Hematology is primarily a study of the formed cellular elements. Physical Characteristics of Blood Thicker (more viscous) than water and flows more slowly than water Temperatu...

Introduction to Hematology Raquel M. Fernandez, RMT, MSPH What is Hematology?  The study of blood.  Hematology is primarily a study of the formed cellular elements. Physical Characteristics of Blood Thicker (more viscous) than water and flows more slowly than water Temperature of 100.4˚F pH 7.4 (7.35-7.45) 8% of total body weight Blood Volume – 5-6 L in average male – 4-5 L in average female Physical Characteristics of Blood Viscosity (thickness) 4-5 (where water = 1) Osmolarity = 300 mOsm or 0.3 Osm Salinity = 0.85% Temperature is 38˚C, slightly higher than “normal” body temp.  Functions of Blood Blood performs a number of functions dealing with: – Substance distribution – Regulation of blood levels of particular substances – Body protection  Blood Functions: Distribution Blood transports: – Oxygen from the lungs and nutrients from the digestive tract – Metabolic wastes from cells to the lungs and kidneys for elimination – Hormones from endocrine glands to target organs  Blood Functions: Regulation Blood maintains: – Appropriate body temperature by absorbing and distributing heat to other parts of the body – Normal pH in body tissues using buffer systems – Adequate fluid volume in the circulatory system  Blood Functions: Protection Blood prevents blood loss by: – Activating plasma proteins and platelets – Initiating clot formation when a vessel is broken Blood prevents infection by: – Synthesizing and utilizing antibodies – Activating complement proteins – Activating WBCs to defend the body against foreign invaders  Blood Components 55% plasma : 7-8 % dissolved substances (sugars, amino acids, lipids and vitamins), ions, dissolved gases, hormones 45% cellular elements: 99% of this is RBC’s ; 1% WBC’s and Platelets  1% found in buffy coat  Composed of Platelets and  Leukocytes – Neutrophils – Eosinophils – Basophils – Monocytes – Lymphocytes BASIC METHODS OF HEMATOLOGICAL EXAMINATIONS Routine Method of Examination Full Blood Count (CBC) – Red cells – RBC,PCV, Hb, red cell indices, reticulocytes – White cells – WBC, leukocyte differential – Platelets Morphological examination – Blood film preparation – stain  Blood Collection Three general procedures for blood collection – Venipuncture – Arterial puncture (ABG) – Skin puncture (pediatric patient) Technique for Venous Puncture Verify requisitions Client identification Specimen required (Fasting or non- fasting) Inform client of the procedure Proper positioning of the client Preparation of equipment and proper labeling Venipuncture Equipment Evacuation system (VACUTAINER) –special double-pointed needle, needle holder, and collection tubes Needle and syringe system – use a sterile needle and a syringe to draw blood specimen Butterfly system – winged infusion set and syringe Collection tubes – must mix blood with appropriate sample containers 18 VACUTAINER  Venipuncture Equipment Specimen collection trays – Hold all equipment necessary – Carts also used Technique for Venous Puncture Selection of suitable vein for puncture Cleanse site with 70% alcohol or 1% iodine-saturated swabstick Apply tourniquet Perform venipuncture (15-30˚angle) Release tourniquet Place a sterile cotton and apply pressure Technique for Venous Puncture Withdraw needle Transfer specimen Check condition of the patient Dispose used materials  Phlebotomy Complications Ecchymosis (Bruise) Hemoconcentration - Prolonged application of a tourniquet results in increase blood concentration Hematoma - missed vein; needle goes through the vein or just partially in the vein Collapse of small vein - Excessive pull on syringe plunger  Phlebotomy Complications Client’s syncope Excessive bleeding Vein thrombosis Infection of the site of venepuncture  Order of Draw Draw specimens into non-additive tubes first before tubes with additives Fill additive containing tubes in the following order: – Blood culture bottles – Red stopper – Blue stopper – Green stopper – Lavender stopper – Gray stopper Commonly Used Evacuated Tubes  Group Order of Draw Culture Tubes Navy Blue Top: Trace Metals Analysis  Group Order of Draw Red and Gold (order does Light Blue: Coagulation not matter  Group Order of Draw Green Top: Heparin EDTA K3 or K2  Group Order of Draw Gray Top: Na Flouride : ACD A then B Color Code: 1. Gold or 'Tiger' Red/Black Top: These colour coded vacutainers are utilized in chemistry, immunology and serology determinations. They contain no other additives other than clot activator and gel for serum separation. 2. Orange or Grey/ Yellow 'Tiger' Top: Orange or Grey/Yellow 'Tiger' top vacutainers are utilized for STAT serum testing. They contain Thrombin, a rapid clot activator. 3. Green: Green top vacutainers contains Sodium Heparin or Lithium Heparin that inactivate thrombin and thromboplastin. They are useful in plasma determinations. 4. Purple or lavender: Purple tubes are used for whole blood is required analysis. They are utilized for complete blood counts (CBC), blood smears, blood typing and screening. These tubes have the potassium salt of EDTA an anticoagulant. 5. Grey: These tubes have sodium fluoride and potassium oxalate and are used for blood glucose determination. 6. Light blue: These tubes have a reversible anticoagulant sodium citrate in measured amount and useful in blood coagulation assays like prothrombin time and partial thromboplastin time. 7. Dark Blue: These tubes contain added anticoagulant sodium heparin or EDTA as an additive. These tubes are primarily used for trace metal analysis and toxicology tests. 8. Red tubes (glass): These are additive free vacutainers used for tests for antibodies, chemistry and drugs. 9. Light yellow: These tubes contain sodium polyanethol sulfonate (SPS) and acid-citrate-dextrose (ACD) as an additive. These are used for blood culture specimens, HLA phenotyping and parental testing. 10. Tan: These tubes lead free and hence used for lead content determinations. In addition to the color code, the plastic caps also have typical indicators. Opaque caps indicate Vacutainer tubes with a normal vacuum. Translucent-caps indicate Vacutainer tubes with a lower vacuum. Weaker suction tubes are suitable in elderly carrying the risk venous collapse during vacuum suction.  Capillary Blood A mixture of venous blood, arterial blood and tissue fluid When the puncture site is warmed, the specimen more closely resembles arterial blood WBC counts higher by 15-20% than in venous specimens Capillary or Skin Puncture  Superficial puncture of skin with sharp point to draw small amount of blood.  Collected in small, calibrated glass tubes, slides, or reagent strips. 34 To whom is skin puncture performed? often performed in NB in pediatric patients less than 1 year severely burned adults those whose veins are being reserved for therapeutic purposes elderly patients with fragile veins Capillary Blood Collection Sites May be performed on the heel or finger In infants the finger should not be punctured Heel Puncture site  Capillary Puncture Performing the puncture – Wear appropriate PPE – Perform the puncture in one steady motion >> – Wipe away the first drop of blood – Collect in capillary tubes or other capillary collection device >>  Preservation of Blood For many purposes blood may be safely preserved at 4˚C in refrigerator. Before procedure, the blood should be first allowed to warm up to room temperature then mixed preferably by rotation for at least 2 mins.  Effects on Blood sample RBC’s start to swell resulting in increase in PCV Reticulocyte count decrease as early as 6 hours Osmotic fragility increases PT slowly increases Red cells may progress to crenation and sphering The nucleated red cells disappear from the blood within 1-2 days