HEMATOLOGY

                     HEMATOLOGY 

                    INTRODUCTION TO HEMATOLOGY 

DEFINITION & IMPORTANCE 

Hematology is the branch of internal medicine, physiology, pathology clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood forming organs, and blood diseases.

hematology includes the study of etiology, diagnosis, treatment, prognosis and prevention of blood diseases.

HEMATOLOGY 

Blood diseases affect the production of blood and its components, such as blood cells, hemoglobin, blood proteins, the mechanism of coagulation, etc.

Physicians specialized in hematology are known as hematologists. their routine work mainly includes the care and treatment of patients with hematological diseases.investigation of these diseases using blood films and bone marrow slides under the microscope, interpreting various hematological test result. in some Institutions, hematologists also manage the hematology laboratory, physician are also important person in hematology laboratories,and most commonly manage them, are pathologist specialized in the diagnosis of hematological diseases, referred to as hematopathologists. hematologists and hematopathologists generally work in conjunction for formulate a diagnosis and deliver the most appropriate therapy if needed. hematologists may specialized further or have special interest, for example in:

• Treating bleeding disorder and coagulation disorders such as haemophilia and idiopathic thrombocytopenia purpura
• Treating hematological malignancies such as various types of lymphoma and leukaemia
• Treating hemoglobinopathies
• In the science of blood transfusion and the work of a blood bank and transfusion medicine
• In bone marrow and stem cells transplantation such as purpose of treatment of different malignancy

The phlebotomist draw blood from patients. it is usually by veinpuncture. blood specimens are treated differently for various tests by the time of its collection. for example, collected blood is needed for Chemistry while whole blood is required for hematological investigation. technician must carefully identify the patients, draw blood according to the requirement of the test, and process it accordingly. any mistake in the identification makes the specimen useless and any delay in getting it to the laboratory may yield wrong result.

various test performed

In a clinical laboratory the hemetalogical department perform numerous different test on blood. the most commonly performed test is the complete blood count (CBC) and also called full blood Count (FBC).these test includes are:-

• HB (haemoglobin)
• TLC (total leukocyte count)
• DLC (different leukocyte count)
• ESR (erythrocyte sedimentation rate)
• Total RBC count (total red blood cell count)
• PCV (packed cell volume)
• MCV (means cell volume)
• MCH (mean cell hemoglobin)
• MCHC (means cell hemoglobin concentration)
• Pleteletcount

Special test performed

Studies of blood coagulation is a sub-speciality of hematology; basic general coagulation test are BT (bleeding time), CT (clotting time) the thrombin time PT and partial thromboplastin time PTT. another common hematology test is the erythrocyte  sedimentation rate ESR.

Test used in the investigation of hematological problems include:-

• Complete blood count
• Erythrocyte sedimentation rate (ESR)
• Blood film, peripheral blood film
• Bone marrow examination
• Haematocrit
• Red cell count
• White cell count
• Prothrombin time
• Partial thromboplastin time (PTT)
• Activated partial thromboplastin time (APTT)
• Thrombin time thrombin
• Protein electrophoresis
• Hemoglobin electrophoresis
• MCV
• MCH
• MCHC
• Differential leukocyte count
• Reticulocyte count
• Eosinophil count
• Platelet count
• Screening of Sickle Cell anaemia
• Estimation of fetal hemoglobin
• Osmotic fragility test
• Heinz body preparation.
• Laboratory organisation
• Functional components of clinical laboratories

The clinical Laboratories can be attached to a hospital or it can be an independent laboratory. in either case, a pathologist is incharge of the laboratory, who is awarded with the degree of medicine and specialized in pathology. the medical laboratory technicians, on the other hand, holds a degree on diploma in MLT and receives one or two years of clinical laboratory training at lower level. the Diagnostic results obtained by the Technologist or technicians are entered into the request report from the the patient and are signed by the pathologist at the end of the day for external communication. all internal Communications, howevre, will bear the signature of the technician preferably Technologist with the date.

Organisational structure of clinical Laboratories

From the organisational point of view the hospital classifies the medical laboratory as a part of special Diagnostic services. in order to functional properly The laboratory is divided into several components. these components are artificial division made according to the convenience of the laboratory but they can be grouped differentially, depending on the work load and number of employees. ideally the supervisor, who is a Technologist will be incharge of the section and the technician (bench workers) will work under the supervision, communicate which external Agencies, accomplish paperwork, ordering of supplies, purchase of equipment, equipment maintenance, keeping of Records, checking the inventory, providing current information to technicians and corresponding with pathologist and physicians. these ideal situation really exists in developing countries. most technicians are "on the job trained" (OJT) and in small Laboratories they work single handed with probably one additional helper to perform non technical work such as sterilization, distillation, preparation of snaps etc. irrespective organizational structures, the functional components of the clinical laboratory can be listed as follows:-

Hematology

HEMATOLOGY

Blood bank or immunohematology

Microbiology

   (a) Bacteriology

   (b) Mycology

   (c) Parasitology

Serology or immunology

Clinical pathology

Clinical biochemistry

Histology and cytology

In some hospitals there is a team of phlebotomists whose main function is a draw blood specimen from indoor and outdoor patients.

The patient submit the request from the physician to register at the receiving desk. following the registration appropriate specimen is collected and dispatched to the specific sections for the laboratory testing. the laboratory may also have a receiving window which receives the specimen from ward or outdoor blood drawing area.

Hematology

The hematology section of the laboratory is primarily involved in the microscopic examination of blood along with physical examination of whole blood and determination of haemoglobin. the diagnosis of blood related disorder like anaemia and leukaemia largely depends on the hematological and peripheral blood film findings. the hematology laboratory also undertake investigation for bleeding disorders. this involves a search for the missing coagulation factor that affect the clotting process. other test including determination of bleeding time, clotting time and platelet count.

Blood banking

Blood banking is a also known as immunohaematology as it is involves antigen-antibody (immunologic) reaction which is associated with red blood cells. the primary function of the blood bank is to provide appropriate blood to the patient for transfusion. transfusion of mismatched blood can be fatal. because of the critical nature of this field, the technicians are expected to be highly proficient in performing blood compatibility testing. transfusion reaction due to technical error do not commonly occurs but clerical mistake bring the higher risk. hence, proper recorder proper records and labelling are essential.

Microbiology

Infection is the signal most important cause of illness in developing countries. the infection can be viral, bacterial, mycotic or parasitic. the responsibilities of the microbiology section include microscopic observation of the specimen, its culture and identification of the offending Pathogenic micro-organism.

Parasitology

Parrasitology is a part of microbiology but is separated out from the latter because of the different type of specimen handled (mostly fecal material) and the different laboratory technique. Unlike the advanced countries. parasitology is one of the most active areas in clinical laboratory operation in developing countries. most common activity is the wet preparation of fecal material for microscopic observation in search of intestinal parasite infection.

Serology

Serology in general refers to the detection of antibodies in serum which are produced by the body as a result of invasion of by infectious agents. the term immunology is often confused with serology. in the case of serology only serum specimens are study while immunology may involve other specimens. in both cases, the central features is the study of the antigen antibody (immunologic) reaction, by this it is possible to identify such infectious agents which cannot be cultured in the laboratory. immunochemistry is an offspring of immunology but is applied extensively in clinical biochemistry for the assay of hormones and for therapeutic drug monitoring. pregnancy testing today has become relatively easy with the application of serologic principles.

Clinical pathology

The term pathology has a different condition. Initially it was used to imply all areas of Hospital Laboratories services. It is still used in this respect in many centres.However, in an occasional institution it is applied to less well defined areas such as microscopic examination of body fluid and faeces. A variety of diagnosis are made through clinical microscopy such as renal disorder (urine) meningeal disease (CSF), fertility status of men (semen) and intestinal bleeding (stool).

Histopathology and Cytology

Histological examination involves the microscopic study of tissue histopathology in order to find out any abnormality. The activities of Histology laboratory include fixing, section cutting, and staining of thin section tissues, which are done by the histotechnologist, the pathologist finally examines the prepared sections and is directly involved in giving opinion on tissue sections. he use his knowledge and experience and make and objective evaluations to decide the the precise nature of lesson (disease). he has often to make highly important decisions such as whether the lesson is malignant or benign.

Cytology, on the other hand, studies cells. Its general functions are the same as those of the Histology laboratory except that there is no need to Cut sections. Cytological investigation can diagnose many types of cancers and the inflammatory conditions. Increasing use is made to the study of cells and the inflammatory conditions and (case off) cells from various tissues. When a tumor is being formed, cells are shed from the effect area as well as from normal ones; in fact, the new growth cells are likely to exfoliate  more rapidly than those from normal areas. specimens commonly used for exfoliative cytology are the vaginal smear urine and sputum.

Clinical Biochemistry

Technicians working in the clinical biochemistry section analyze the chemical constituents of body Fluids, particularly serum. instrumental analysis, use of commercial kits and Automations are the integral parts of the clinical biochemistry laboratory activities. biochemical analysis are most helpful in the diagnosis of organ related disorders and metabolic disorders liver, kidney, pancreas etc.

Phlebotomy

Phlebotomist draws blood from patients. it is usually done by  venipuncture. Blood specimens treated  differentialy for various test by the time of its collection. For example, collected blood is needed for Chemistry while whole blood is required for hematological investigation. As the results are as good as the specimen, the phlebotomist has a very responsible job. he must carefully identify the patient, draw blood according to the the requirement of the test, and process it accordingly.  Any mistake Hindi identification makes the specimen useless and any delay in getting it to laboratory yield wrong result.

 Basic needs of clinical laboratory

The basic needs for a typical small size clinical laboratory performing routine Diagnostic test are listed below. if electricity is not available, install a generator. instruction manual provided by the manufacturer of various equipment is extremely helpful under conditions in order to troubleshoot the problem.

1:- Good quality microscope. with oil immersion objective along with acessories (illumination cover etc.)

2:- colorimeter and accessories (cuvette, filters, etc.)

3:- bunsen burner and butane gas.

4:- centrifuge with accessories (centrifuge tubes). if electricity is not available, use hand centrifuge.

5:- water bath (electrically operated or gas operated) temperature can be maintained only with an electrical water bath.

6:- balance - physical and chemical

7:-Test tube rack

8:- inoculating niddle or Platinum wire with holder.

9:- burette stand

10:- tripod stand

11:- distillation set

12:- glassware and plasticware:- this includes a wide variety of materials, both volumetric and non volumetric glassware.  the volumetric glassware include graduated cylinders 500, 100, 50 and 1 ml; volumetric 20, 10, 5, 1 ml. the nun volumetric glassware includes rimless test tubes 15, 10 and 5 ml, immersion oil bottle, dropping bottle 100ml, narrow mouth reagent bottle, polythene bottle, wash bottle, funnel, erlenmeyer flask, beakers, graduated cylinders and petri dishes.

13:- filter paper

14:- haemocytometer

15:-ESR tube and rack

16:- microscope slides, coverslips and cavity slides for serology

17:-Weighing scoop

18:-Glass tubing

       Supplies:-filter paper, grease pencil, laboratory record book, cotton gauze, swab (cotton-tipped)

19:-Thermometer

20:-Incubator

21:-Oven

22:-Refrigerator

23:-Work bench with divided drawer to hold pipettes

24:-Water source  (over head tank)

25:-Shelves for keeping reagents

26:-Empty pencilling vials for blood collection

27:-Deionizer column

28:-Pressure cooker or sterilizer

29:-Stains and reagents

30:-Inoculating loops and needles.

31:-Generator

histopathology