LABORATORY INVESTIGATIONS Dr. Rupak Sethuraman

SPECIFIC LEARNING OBJECTIVES INTRODUCTION INTRODUCTION VARIOUS LABORATORY INVESTIGATIONS VARIOUS LABORATORY INVESTIGATIONS THEIR CLINICAL IMPORTANCE THEIR CLINICAL IMPORTANCE

INTRODUCTION Laboratory investigations refers to different procedures which are performed in the laboratory, which includes estimating the value of specific parameters as well as microscopic investigations. Laboratory investigations refers to different procedures which are performed in the laboratory, which includes estimating the value of specific parameters as well as microscopic investigations. These act as diagnostic aids for the clinician. These act as diagnostic aids for the clinician. Broadly divided into hematological and other investigations. Broadly divided into hematological and other investigations.

HEMATOLOGICAL INVESTIGATIONS DEFINITION :- It refers to measurement and microscopic examination of the formed elements of blood as well as measurement of hemoglobin concentration and chemical constituents of plasma. Blood basically comprises of 3 parts 1. Formed elements (have a definite shape) 2. Plasma 3. Serum = plasma – fibrin. Based on the development of formed elements they can be classified as 1. Myeloid tissue. 2. Lymphoid tissue.

CLASSIFICATION BASED ON THE METHOD CHAIR SIDE 1.HEMOGLOBIN 2.HEMATOCRIT 3.BLEEDING TIME 4.CLOTTING TIME LABORATORY 1.SPECIMEN COLLECTION 2.SMEAR PREPARATION 3.MANUAL PROCEDURES 4.AUTOMATED PROCEDURES etc

BASED ON THE CLINICAL PICTURE 1. COMPLETE BLOOD PICTURE 2. BLOOD CHEMISTRY

COMPLETE BLOOD PICTURE 1. RBC COUNT OR ERYTHROCYTE COUNT 2. HEMOGLOBIN CONCENTRATION 3. HEMATOCRIT OR PACKED CELL VOLUME 4. RED CELL INDICES 5. TOTAL WBC COUNT 6. DIFERENTIAL WBC COUNT 7. BLOOD GROUP 8. PLATELET COUNT

ERYTHROCYTE COUNT ERYTHROCYTE COUNT Normal value is million cells/ cubic mm of blood Increase is called erythrocytosis and decrease is called anemia. Done to investigate different types of anemias.

HEMOGLOBIN CONCENTRATION  Value:- Males gms/dl ; females gms/dl. METHODS:-  MANUAL 1. Sahli’s method 2. Drabkin’s method.  Automated Technicon H6000 system is used.

It is the first investigation if a clinician suspects a patient to be anemic, in which case there is a marked reduction in the hemoglobin concentration. It is the first investigation if a clinician suspects a patient to be anemic, in which case there is a marked reduction in the hemoglobin concentration. It is to be carried out in patients who give a history of anemia or in whom pallor is noticed on clinical examination, either in the eyes or in the oral cavity. It is to be carried out in patients who give a history of anemia or in whom pallor is noticed on clinical examination, either in the eyes or in the oral cavity.

HEMATOCRIT OR PACKED CELL VOLUME  Value 40-50% of total blood. It is the percentage of the blood occupied by the RBC. Method:  Manual:- Wintrobe’s Tube  Automated:- TECHNICON H 6000 COUNTER METHOD.

ERYTHROCYTE INDICES : 1. MEAN CORPUSCULAR HEMOGLOBIN:- MCH= hemoglobin conc. in gms/dl x10 MCH= hemoglobin conc. in gms/dl x10 RBC in millions/ mm 3 RBC in millions/ mm 3 2. MEAN CORPUSCULAR HEMOGLOBIN CONCENTRATION: MCHC=hemoglobin conc. in gms/dl x100 hematocrit 3. MEAN CORPUSCULAR VOLUME: MCV=Hematocrit x10 RBC in millions/ mm 3 These values are used to diagnose different types of anemia.

In case of iron deficiency (microcytic hypochromic) anemia, all the three values MCV, MCH and MCHC are decreased. In case of iron deficiency (microcytic hypochromic) anemia, all the three values MCV, MCH and MCHC are decreased. In case of megaloblastic (macrocytic) anemia, MCV is increased. In case of megaloblastic (macrocytic) anemia, MCV is increased.

TOTAL WBC COUNT:  Value: – 10,000cells/mm3 of blood. Decrease- LEUKOPENIA Decrease- LEUKOPENIA Increase- LEUKOCYTOSIS. Increase- LEUKOCYTOSIS.Method:-  Manual:- NEUBARS COUNTING CHAMBER NEUBARS COUNTING CHAMBER Turk’s fluid Turk’s fluid  Automated: Technicon H 6000 Technicon H 6000

 Indications for WBC count  Leukocytosis Physiologic Acute and Chronic Infections PolycythemiaLeukemia  Leukopenia Influenza Cyclic neutropenia Typhoid and Para typhoid Patient on anti cancer chemotherapy Aplastic anemia

DIFFERENTIAL WBC COUNT  Granulocytes : Neutrophils43-77% Neutrophils43-77% Eosinophils0-4% Eosinophils0-4% Basophils0-2% Basophils0-2%  Agranulocytes:  Monocytes0-9%  Lymphocytes17-47%

 NEUTROPHILS  Increase Myelogenous Leukemia Myelogenous Leukemia Acute infectious diseases Acute infectious diseases Erythroblastosis Fetalis Erythroblastosis Fetalis Intoxications by drugs and poisons Intoxications by drugs and poisons  Decrease Neutropenia Neutropenia Aplastic Anemia Aplastic Anemia Lymphocytic Leukemia Lymphocytic Leukemia

 EOSINOPHILS  Increase Eosinophilic leukemia Eosinophilic leukemia Allergic diseases Allergic diseases Scarlet fever Scarlet fever Hodgkins lymphoma Hodgkins lymphoma Protozoal infections Protozoal infections  Decrease Typhoid fever Typhoid fever Aplastic anemia Aplastic anemia

 MONOCYTES  Increase Monocytic leukemia Monocytic leukemia Infectious mononucleosis Infectious mononucleosis Hodgkins lymphoma Hodgkins lymphoma Malaria Malaria Tuberculosis Tuberculosis  Decrease Aplastic anemia Aplastic anemia

 LYMPHOCYTES  Increase Lymphocytic leukemia Lymphocytic leukemia Mumps Mumps Whooping cough Whooping cough Chronic infections Chronic infections  Decrease Aplastic anemia Aplastic anemia Myelogeneous leukemia Myelogeneous leukemia

BLOOD GROUP GROUP A GROUP A GROUP B GROUP B GROUP AB GROUP AB GROUP O GROUP O RH +VE OR –VE RH +VE OR –VE

PLATELET COUNT: Value:-1,50,000 to 4,50,000/mm 3 of blood. < 50,000 spontaneous bleeding Size about 2-5microns

 Increase in platelet or Thrombocytosis Polycythemia vera Hemolytic anemias Chronic myelocytic leukemia Acute rheumatic fever  Decrease in platelet or Thrombocytopenia Thrombocytic purpura Acute leukemia Aplastic anemia Pernicious anemia Hemolytic jaundice

ERYTHROCYTE SEDIMENTATION RATE:- Value:- males 0-15mm/hr in females 0-20mm/hr. Values above normal occurs when changes in plasma protein causes RBCs to aggregate. It is a non specific test and only indicates the presence of an infection and it can’t diagnose the specific disease. Indications: Tuberculosis Tuberculosis Osteomyelitis Osteomyelitis Collagen disease Collagen disease Nephritis Nephritis Rheumatic fever Rheumatic fever

TESTS OF PLASMA 1. CHAIR SIDE TESTS  BLEEDING TIME:  Value:-5 to 8minutes.  Abnormal value indicates vessel wall or platelet abnormality.  CLOTTING TIME:  Value:-8 to 10 minutes.  Abnormal value indicates abnormality in any of the clotting factors.

LABORATORY TEST FOR BLEEDING AND CLOTTING TIME 1. PROTHROMBIN TIME 2. PARTIAL THROMBOPLASTIN TIME AND SPECIFIC CLOTTING FACTOR ASSAY 3. CLOT RETRACTION 4. PLATELET SURVIVAL TIME 5. TEST FOR FIBRINOLYSIS,CLOT LYSIS AND FIBRIN SPLIT PRODUCTS

BLOOD GLUCOSE TESTS 1. Random Blood Sugar 2. Fasting blood sugar 3. Two Hour Postprandial Blood sugar 4. Glycosylated Hemoglobin (HbA1c)

SERUM TESTS 1. Serum Calcium,Phosphorus, Alkaline Phosphatase And Leukocyte Alkaline Phosphatase 2. Serum Uric Acid 3. Serum Albumin And Globulin, total Serum Proteins. 4. Serum Bilirubin Concentration.

 SERUM CALCIUM Normal value mg/dl Normal value mg/dl  Increase Metastatic osseous neoplasms Osteogenesis imperfecta Paget’s disease Hyperparathyroidism  Decrease OsteomalaciaHypoparathyroidism

 SERUM PHOSPHORUS 2 – 5 mg/dl  Increased Tetany Tetany  Decreased Osteomalacia Osteomalacia Hyperparathyroidism Hyperparathyroidism

 SERUM ALKALINE PHOSPHATAS E 2-5 Bodansky units/dl  Increased Paget’s disease- Goes till 250 Bodansky units/dl RicketsHyperparathyroidism Osteogenesis Imperfecta

 SERUM URIC ACID MALE 4-8.5mg/dl MALE 4-8.5mg/dl FEMALE mg/dl  Increase TMJ diseases TMJ diseases Gout Gout Uric acid containing salivary calculi Uric acid containing salivary calculi

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