Types of laboratories
In most countries, there are likely to be some laboratories with limited resources, but in economic distressed countries, there are few laboratories with highly trained technologists and sophisticated equipment. In these countries therefore, i t is not unusual for laboratory tests to be carried out by nurses and ordelies in outpatient consulting rooms, corridors and in rural health centres.
Understaffing,poor morale, inadequate equipment and erratic supplies of reagents are chronic problems in laboratories in poorer countries and these factors have a major impact on the range and quality of services that can be offered. Many smaller laboratories are multifunctional, performing Haematology, Parasitology, Clinical chemistry and Bacteriology tests. A blood transfusion service is usually available at the larger institutions and unless there is a national blood service, laboratory staff will be responsible for donor selection, blood collection and issuing of blood. If there is no organisation of public health laboratories, routine laboratories will be required to provide high quality health surveillance data for epidemiological and public health monitoring.
In a number of economically distressed countries, the difficulties are compounded by the fact that health services are becoming overwhelmed by expanding epidemics of HIV/AIDS(Human immunodeficiency vírus/Acquired immune deficiency syndrome), tuberculosis and malária. Diagnosis and monitoring of these diseases require a healthy,robust and reliable laboratory service. Thus malária diagnosis must be confirmed by a laboratory test because other disorders can masquerade clinically as malária. The diagnosis of tuberculosis may require boné marrow aspiration and culture and trephine biospy examination, especially in patients who are also HIV positive because in these cases sputum tests for acid fast organisms are frequently negative. Monitoring of HIV progression to AIDS and effectiveness of antiretroviral therapy requires Haemoglobin estimation, CD4-poistive lymphocyte counts and plasma viral load estimation.
The main purpose of this topic-(Haematology practice in distressed economy) is to point towards an effective haematology service that can be provided despite serious limitations. In planning such a service, it becomes imperative to identify what facilities are needed and to plan a network for referral when a clinical problem requires investigations beyond the facilities and expertise that are available locally. Thus, for example, successful management of haematological malignancies in countries with limited resources might involve the participation of local haematologists forming partinership with institutions in developed countries with consequent adaptation of standard protocols and improvement of local supportive care facilities.
ORGANIZATION OF CLINICAL LABORATORY SERVICE
In a depressed economic countries, clinical laboratory services may be considered at three levels according to their size, staffing, and the work they undertake.
They are as follows:
A. Subdistrict facilities including health centres
B. District Hospitals
C. Central-regional and teaching Hospitals.
The level A laboratory generally provides the means for helping to determine whether a patient should be referred to the local hospital. It may be simply a Haemoglobin estimation during the clinical consultation or it may be a side room where Basic laboratory tests are often carried out by nurses, assistants etc with no technical qualifications. The Haematology equipment available includes, a simple method of Hb estimation and a microscope for examination of slides for tuberculosis or malária.
Level B…District Hospitals
District hospital laboratories are usually multipurpose performing bacteriological and biochemical as well as Haematological tests. Laboratory staff consists of one or two qualified technologists supported by assistants who often have little or no training. The minimum Haematology equipment includes,microscope,centrifuge and a simple colorimeter for Hb estimation.
Level C…Central and teaching Hospital
At this level the laboratory staff receives multidisciplinary training and each laboratory generally has a specialist technical head, whereas many of the more sénior staff will have received postgraduate training in their chosen discipline( for example, Haematology with Hospital transfusion practice or Bacteriology or Parasitology or Histopathology or Clinical Chemistry). Equipment generally includes;centrifuge,colorimeters, microscopes, Hb electrophoresis equipment and possibly blood bank centrifuges for the separation of blood components and Automated haematology analysers.
In many cases, these have been supplied by donor agencies, but long term funding to support maintenance and training for using these systems is often lacking and consequently they may be unreliable or not used at all owing to a shortage of appropriate reagents and inadequate maintenance and staff training.
AVAILABILITY OF TESTS AT EACH LEVEL
In a distressed economic countries, haematology tests that are available at the different levels of health care services are very variable and depend on local clinical needs, the equipment available, the number of laboratory staff and their technical skills. The following is a general description of the tests that are likely to be required but all may not necessarily be available at the specified levels.
HB estimation by simple method,Thin and THick blood films for malária screen, HIV serology tests supported by voluntary counselling and testing.
A. Hb estimation
B. Blood film morphology, especially to identify the cause of anaemia.
C.Platelet and total white blood cell counts
D.Differential leucocyte count.
E. CD4 lymphocyte count
F. Malaria screening tests (thick and thin films) and rapid immunological test for plasmodium falciparium and others.
G. Screening test for sickle cell anaemia in prevalent áreas.
In addition to tests carried out at level B, the haematology tests offered by level C might include the following;
A. Automated haematology anayzer for complete Blood Count
B. Hb electrophoresis or High performance liquid chromatography (HPLC)
C. HBA2 and HBF determination
D. Glucose-6- phosphate dehydrogenase screen—by fluorescent spot or methaemoglobin reduction method.
E. Flow cytometry immunophenotyping
F. Polymerase chain reaction
G. HIV plasma viral load estimation
H. Bone marrow staining and assessment
I. Blood grouping and compartibility testing
J. Identification of blood group antibodies
K. Basic clotting testing(Thrombin test,Prothrombin test, Kaolin cephalin clotting time test or activated partial thromboplastin time test,fibrinogen assay and other factor assay tests,clotting time test and haemorragic time test)
L. Oral anticoagulant control
M. Blood component separation(plasma,packed cell and platelets,granulocytes etc)