full blood count (fbc) - thyolo hospital, malawi

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This is a presentation made by final year Bachelor of Sciences in Medical Laboratory students [Symon Nayupe and Peace Morrison] from University of Malawi, College of Medicine during their Laboratory practicum at Thyolo District Hospital, Malawi.



2. OBJECTIVE Know FBC its indications, sample collection and result interpretation 3. Full Blood Count/Complete Blood Count Basic screening test Frequently ordered laboratory procedure Provides valuable diagnostic information about patients overall health and response to treatment Quantitative/qualitative Turn around time: 1 hr. 4. FBC Parameters WBC count RBC count Haemoglobin (Hgb) Platelet count WBC differential(5 diff) RBC indices MCV MCH MCHC RDW 5. FBC Indications Detect hematologic disorder, neoplasm, leukemia, or immunologic abnormality Determine the presence of hereditary hematologic abnormality Evaluate known or suspected anemia and related treatment Monitor blood loss and response to blood replacement 6. FBC Indications cont Monitor the effects of physical or emotional stress Monitor fluid imbalances or treatment for fluid imbalances Monitor hematologic status during pregnancy 7. FBC Indications cont Monitor progression of nonhematologic disorders, such as chronic obstructive pulmonary disease, malabsorption syndromes, cancer, and renal disease Monitor response to chemotherapy and evaluate undesired reactions to drugs that may cause blood dyscrasias Provide screening as part of a general physical examination, especially on admission to a health care facility or before surgery 8. FBC Sample Venous blood Heel puncture in newborns Sample in (Ethylenediaminetetraacetic acid) EDTA tube - lavendar top 9. Running the test Manual/ automated analysers 1. Manual WBC and RBC count on neubaeur chamber Differential, plts and RBC morphology on thin smear RBC indices can be calculated using formulas. (1) 2. Automated analysers computerized multichannel analyzers that sort and size cells on the basis of changes in either electrical impedance or light pulses as the cells pass in front of a laser 10. Parameters that constitute FBC and their significance Haemoglobin It is a parameter that is used to measure anaemia. Its expressed in g/dl Various methods are used to measure hb conc. but the cynamethemoglobin method is the preferred method in most automated analyzers Ref. ranges 11.0-17.5 g/dl and low values below the normal range are implicated in most anaemias. 11. MCV Mean cell volume Its the estimation of the individual volume of a cell Measured in fentolitres Reference values; 80-100 fl Low MCV (microcytic anaemia): iron deficiency or thalassaemia. MCV/RCC: < 12 -thal > 12 Fe def. anaemia. High MCV (macrocytic anaemia): folate or vitamin B12 deficiency, medications such as ARVs. 12. Haematocrit (Hct) proportion of blood occupied by erythrocytes. Hct = red cell count x MCV /10 (%). Mean cell haemoglobin (MCH) amount of Hb per red cell. Ref value: 27-34 MCH = Hb / red cell count x10 (pg/cell) 13. Mean cell haemoglobin concentration (MCHC): concentration of Hb per unit red cell volume. MCHC = Hb / Hct x 100 (g/dl). Ref values: 30-35 MCHC > 35 g/dl is associated with hereditary spherocytosis. Low MCHC is typical of iron deficiency anaemia. 14. RDW Red cell distribution width Measured the variability of red cell sizes Large values indicate great variations Help to distinguish IDA from thalasameias (microcytic anaemias) Ref values: 10-20 15. Platelet count Electronically counted by impedence and light scatter. Can be falsely elevated in: Sample is incompletely anticoagulated, indicated by small clots. Platelet clumping. Platelet satellitism Megathrombrocytes Can be decreased in bleeding disorders and elevated in MPNS 16. WBC Count Ref. range 5000 10,000 cells/mm3 Leucocytosis: general increase in WBCs Acute infections Leukaemia, MPNs , Trauma or tissue injury (eg, surgery), Malignant neoplasms - especially bronchogenic carcinoma, Toxins, uremia, coma, eclampsia, thyroid storm Drugsespecially ether;chloroform; quinine; epinephrine(Adrenalin); colony-stimulating factors, Acute hemolysis, Hemorrhage (acute), After splenectomy, Polycythemia vera, Tissue necrosis 17. WBC Count Leukopaenia Viral infections, some bacterial infections, overwhelming bacterial infections , Hypersplenism, Bone marrow depression caused by heavy metal intoxication, ionizing radiation, drugs e.g. (1) Antimetabolites (2) Barbiturates (3) Benzine Primary bone marrow disorders Immune associated neutropaenia Iron deficiency anaemia 18. WBC Differential Neutrophils: neutrophilia increased percentage of neutrophils (greater than 7500/mm3) Inflammation, acute haemorrhage, acute general and localised bacterial infections, tissue necrosis, acute haemolysis , MPNs etc Neutropaenia reduced percentage of neutrophils (less than 3000/mm3 ) Acute, overwhelming bacterial infections (poor prognosis) Viral infections (eg, influenza, infectious hepatitis, mononucleosis Rickettsial diseases, some parasitical diseases (malaria) Drugs, chemicals, toxic agents, radiation 19. WBC Differential Lymphocytes Lymphocytosis: greater than 4500/mm3 lymphocytes Lymphatic leukemia (acute and chronic) lymphoma, Infectious lymphocytosis (occurs mainly in children), Infectious mononucleosis: (1)Caused by Epstein-Barr virus (2)Most common in adolescents and young adults Viral infections, other bacterial infections like TB 20. WBC Differential cont Lymphopaenia: less than 1500/mm3 Chemotherapy, radiation treatment , After administration of ACTH or cortisone (steroids); with ACTH-producing pituitary tumors, Increased loss via gastrointestinal tract owing to obstruction of lymphatic drainage (eg, tumor, Whipples disease, intestinal lymphectasia), Aplastic anemia, Hodgkins disease and other malignancies, Inherited immune disorders, acquired immunodeficiency syndrome (AIDS), and AIDS- immune dysfunction G. Advanced tuberculosis 21. FBC Critical values 22. Quality control in performance of a FBC Pre-analytical factors Samples should not be left to stand for a long time before processing Samples should be kept away from direct sunlight Insufficient samples should be rejected especially to deter the effects of anticoagulant concentrations on FBC results Sample collection should follow proper collection procedures proper labeling, right anticoagulants should be used (EDTA) 23. FBC Quality Control cont Analytical factors Make sure machine is working properly- Controls Establish reference range for the area- lab working on it (critical values) Proper following of laboratory procedures Post-analytical factors Clerical errors Delay in results reaching the pts result keeping Interpretation of results 24. An FBC Case CASE.docx Answers.doc 25. References Haematology in Practice ; F.A. Davis Company, 1915 Archstreet, Philadelphia, USA (2007) A manual of Laboratory and Diagnostic Tests (6th Edi.), Lippincott Williams & Wilkins; 530 Walnut Street, Philadelphia, USA (2000) Daviss Comprehesive Handbook of Laboratory and Diagnostic Tests with Nursing Implications (3rd Edi.); F.A. Davis Company, 1915 Archstreet, Philadelphia, USA (2009) Nurses Manual of Laboratory and Diagnostic Tests (4th Edi.); F.A. Davis Company, 1915 Archstreet, Philadelphia, USA ( 2003) M. Cheesbrough:District Laboratory Practice in Tropical Coutries (2nd Edi.); Cambridge University Press, The Edinburg Building, Cambridge, UK (2006)