Introduction to Haematology PDF

Introduction to Haematology Peter Abel What is Blood  CENTRIFUGATION OF ANTICOAGULATED BLOOD Plasma Buffy Coat (WBCs & Platelets) Red Cells  Haemopoiesis Blood volume of normal adult - 7% body wt. (70ml./Kg) 45% cellular...

Introduction to Haematology Peter Abel What is Blood  CENTRIFUGATION OF ANTICOAGULATED BLOOD Plasma Buffy Coat (WBCs & Platelets) Red Cells  Haemopoiesis Blood volume of normal adult - 7% body wt. (70ml./Kg) 45% cellular elements, 55% plasma. erythrocytes leucocytes thrombocytes Plasma contains water, proteins, electrolytes, hormones, substances from GI tract, products of metabolism.  Haemopoiesis All blood cells have a finite life span. RBC -120 days WBC - between 4 hours and 10 years. PLT - 10-14 days. Cell loss from ageing, physiological consumption and loss from the body.  Sites of Haemopoiesis Foetus 0-2 months (yolk sac) 2-7 months (liver, spleen) 5-9 months (bone marrow) Infants Bone marrow (all bones) Adults Vertebrae, ribs, sternum, skull, sacrum, pelvis, proximal ends of femur. Sites of Haemopoiesis Sites of Haemopoiesis Haemopoietic Stem and Progenitor cells  Normal peripheral blood cells - Erythrocytes Red blood cells in Cell easily deformed and normal peripheral can pass through small blood are circular capillaries without biconcave discs of rupture. 8m diameter. Cell has surface to volume ratio that enables optimal gaseous exchange.  Normal peripheral blood cells - Leucocytes Granulocytes Neutrophils Basophils Eosinophils Normal peripheral blood cells - Leucocytes Other white blood cells. Monocytes Lymphocytes B - Cells T - Cells Normal peripheral blood cells - Platelets  Haemoglobin - synthesis and structure Main function of red cells is to carry O2 to tissues and to return CO2 from tissues to lungs. Haemoglobin is a specialised protein that achieves this task. Each red cell has approx. 640 million Hb molecules. Hb molecule has four globin (polypeptide) chains each containing a haem group. Haemoglobin - synthesis and structure  What is anaemia “A reduction in oxygen-carrying capacity due to a lower haemoglobin concentration than is usual for that individual.” Wide range of haemoglobin found in healthy populations. Haemoglobin concentration dependant on red cell mass. Anaemia occurs when red cell destruction is greater than red cell production.  Anaemia C la s s ifi ca tio n o f a n a e m ia M ic ro c y tic hy p o c h ro m ic N o rm o c y tic no rm o c h ro m ic M a c ro c y tic M C V < 8 0 fl M C V 8 0 -9 5 fl M C V > 9 5 fl M C H < 2 7 pg M C H > 2 6 pg Iro n d efi c ie n cy H a e m oly tic a na e m ias M e g a lob la s tic an a e m ia T h a la s s a e m ia A c u te b lo od lo ss A lc o h ol L e a d p o iso n ing R e n a l d is e a se L iv e r d is e a se Blood film - Red cell morphology  Clinical features of Anaemia Body adapts to anaemia. Tachycardia. Shortness of breath. Weakness, Lethargy. Palpitations, Headaches. Confusion. Pallor of conjuctival mucosa and of nail bed. Retinal haemorrhages. Clinical features of Anaemia  Causes of Iron deficiency anaemia Reduced Increased absorption demand of due to growth Depletion of dietry pregnancy, Iron stores deficiency lactation or malabsorpti on. Blood loss, physiological or pathological Iron deficiency anaemia  Investigation of IDA RBC indices and film Bone marrow iron Serum iron and ferritin  Treatment for IDA Treat underlying cause. Oral iron.  Blood samples Samples usually taken by phlebotomist May be capillary (from a finger prick) or venous (from the vein) Capillary blood usually used for Point of Care testing (P.O.C.T.) Venous blood usually taken from antecubital vein using ‘vacutainer’ Example of Phlebotomy technique – ‘venepuncture’ 26  Venepuncture Must take blood from plain tubes first to avoid contamination Must identify patient verbally and obtain consent Use tubes with the correct anticoagulant for the tests required. Coag samples must be correct volume. Serum- clotted blood with no coagulation factors Plasma – anticoagulated blood with coagulation factors  Blood collection system + anticoagulant types EDTA is anticoagulant of choice for Blood cell Counting and associated tests 28  Bone Marrow Taken to examine cellular morphology usually for lymphoproliferative disorders and haematological disease. Can take fluid which is spread onto a slide for the haematology department or a solid trephine biopsy for examination by the histology department. Collection of bone marrow  Point of care testing Used either as adjunct to laboratory or outside the hospital for primary health care Useful for urgent results in acute wards such as ITU, A&E etc Also useful for rural doctors surgeries Important that laboratories maintain control of instrument calibration, QC, training, instrument maintenance and specimen collection  The ‘Full Blood Count’ Key analyses:- Haemoglobin level White Blood Cell count (Leucocytes) including automated differential Red Blood Cell count (Erythrocytes) Platelet Count (Thrombocytes) Red cell parameters 32  Laboratory aspects - FBC Full blood count is first line test in haematology. Usually measure 8-20 parameters in FBC Automated methods preferable, highly accurate and precise. When blood abnormality detected instrument ‘flags’ aberrant results. Parameters measured Hb, RBC, WBC, Differential, Platelets, MCV, Hct, MCH, MCHC, RDW, PDW, MPV 33  NORMAL HAEMATOLOGICAL VALUES Neutrophils 2.0-7.5 x 109/l 40 - 75% Lymphocytes 1.5 – 4.0 x109/l 20 –45% Monocytes 0.2 – 0.8 x109/l 2 – 10% Eosinophilia 0.04 – 0.4 x109/l 1 – 6% Basophils