Role of biomedical laboratory testing in detection andmanagement of diseaseMedical laboratory testing has a vital role in the detectionand management of disease in patients. Laboratory tests are used to verify thepresence, magnitude or absence of a disease, the tests are also used to monitorthe effectiveness of a treatment. Laboratory testing includes test resultsbeing analysed, laboratory scientists perform various biological, chemical,microscopic and bacteriologicaltests which require important analytical and independent verdict.Whole population screening In medicine screening is used in a population to identify the presence ofan undiagnosed disease in patients who do not demonstrate signs or symptoms. Thiscould include patients with an unrecognized symptomatic disease. Blood samples are the most common samples used forpopulation screening are. It is essential to collect the samples in the easiestand fastest manner, as this is the best method to analyse the large number ofpeople.
The sample collected then undergoes biomedical laboratory testing.An example of a screening test is CA-125 blood test, this isone of the tests used in screening for ovarian cancer in a population. a CA-125test can be used to identify early signs of ovarian cancer in a group of womenwith a high risk of the disease. Once the sample is received in the laboratory,the test measures the amount of CA-125 in the blood.Disease diagnosisdiagnosis is the identification of disease or condition by examining theindividual’s symptoms and signs. A diagnosis of a disease is based onlaboratory reports or test results, not just on the physical examination of thepatient. A diagnosis of a diseases requires an examination of the symptomsdisplayed, as well as a laboratory attribute of the pathogen involved. laboratory tests play an important role in detection ofdisease, due to their usefulness in diagnosing and managing the most commondiseases and conditions observed in outpatient practice.
Laboratory tests assist in better diagnosis and managementof diseases and conditions seen in patients. Decisions on an individual’s diagnosis, treatment andmonitoring are usually dependent on a range of laboratory-based results. Blood tests arean example of laboratory testing, the results are used for diagnosis.
At timesa blood disorder may not present any symptoms or signs in a patient, but adisorder can be later discovered when a laboratory test is done. This shows theimportance of laboratory testing in disease detection. MonitoringDisease monitoring is a system which is used to observe the spread of adisease, it is carried out to establish patterns of progression. An example ofa disease that is monitored is prostate cancer. When a patient is diagnosedwith prostate cancer this does not mean the patient has to immediately undergotreatment, it is common for doctors to keep an eye on the patient, rather thanstarting treatment on the patient straight away. The patient will have regulartests to examine whether the prostate cancer is remaining in the same place orbeginning to grow. If it is indicated through test results that the cancer isgrowing or changing in any way the patient can then begin treatment.There are 2 techniques used to monitor prostate cancer;active surveillance and watchful waiting.
The method used depends on the individual’streatment options, the patient will have active surveillance if the doctor’sobjective is to cure the cancer if it begins to grow. If the patient haswatchful waiting this is due to the doctors aim to control the cancer.Disease management is a method widely used to teach patientshow to manage their disease. Patients are shown hoe to take responsibility forunderstanding how to take good care of themselves. Patients are taught how toavoid potential problems, and certain actions which can make the disease worse,of their health problem.
Pathology disciplines HaematologyHaematology involves the study of blood and blood diseases, it also focuseson immunologic, blood clotting and vascular systems. Haematology allowsscientists to better understand many diseases. It involves treating diseasesthat affect the production of blood and its elements, for instance blood cells,haemoglobin, blood proteins, bone marrow, platelets and coagulation.Complete Blood Count test A complete blood count is a test that gives a general overview of a patient’shealth.
The test is used to acquire the measurements of red blood cells, whiteblood cells, haemoglobin, haematocrit and platelets. A complete blood countreveals any abnormal increases or decreases in cell counts, which calls forfurther evaluation as it may indicate a hidden medical condition. The test iscarried out by collecting the blood in a test tube which contains ananticoagulant to prevent the blood from clotting. In the laboratory the blood isplaced into an analyser, which analyses the different elements in the blood. Withinthis test the numbers and types of different cells present in the blood arecounted.
The results are then either printed out or sent to a computer forexamination. The reason a complete blood count is carried out for variousreasons such as to review a patient’s overall health, to diagnose a medicalcondition, to monitor a medical condition and to monitor a treatment. Coagulation screening testsCoagulation tests are used to measure the blood’s ability to clot, and the timetaken for the clot to form. This test assesses any risk of excessive bleedingor developing clots in your blood vessels as well as identifying any clottingdisorders. Clotting disorders can cause a dangerous amount of bleeding orclotting. The test is carried out by collecting a blood sample into a bottlethat contains a chemical which stops the blood from clotting. The blood sampleis then analysed in the laboratory. A number of tests are done on the sampleblood, including the ‘prothrombin time’ (PT) and the ‘activated partialthromboplastin time’ (APTT).
PT and APTT measure the time taken for a bloodclot to develop after certain activating chemicals are added into the sample.If the time taken for a blood clot to form is longer than a normal bloodsample, it is indicated one or more clotting factors are low or not present. Theaim is then to identify which clotting factors these may be. Microbiology Microbiology involves the investigation of infectious diseases, microbiologyfocuses on specific bacteria, viruses, fungi and parasites that could becausing a patient symptom. This involves culturing particular bacterium thatimitates a suitable environment for the microorganism, the results are thenexamined under a microscope.
The sensitivity of the bacteria to antibiotics isalso measure in order to work out treatment.Blood culture testBlood cultures tests are commonly used to identify the presence of any bacteriaor fungi within the blood. The test is carried out by collecting blood in twobottles, an aerobic and anaerobic bottle. In the laboratory the bottles areplaced into a BD Bactec FX, this is where the growth of bacteria is monitored.If growth is suspected, a gram stain is performed. Gram stain allows betterunderstanding of the patient’s infection.
The test is used to detect the types present,and to devise the appropriate antimicrobial treatment. It’s vital to test forblood infections as they can lead to severe complications.Stool TestA stool analysis is a series of tests performed on a stool sample, Afterthe collection of the sample, it is sent to laboratory for testing, in order toidentify the presence or absence of a medical condition. A patent may berequired to provide a stool sample to help diagnose or rule out a particularhealth condition. Stools contain the same bacteria and substances present inthe digestive system, by analysing the levels of these substances and bacteriain your stools, you can work out what’s happening in the digestive system.Fungal TestsFungal tests are used to detect any fungal infection; the tests determine thespecificity of the fugus present.
The fungi may be isolated and grown forsusceptibility testing. Specimens for fungal microscopy and culture mayinclude; scrapings of skin, hair pulled from the roots, nail clipping, skinbiopsy and a moist swab from a mucosal surface. In the laboratory the fungus isgrown in a culture, incubated at 25-30ºC. The sample collected is inoculatedinto a medium. The culture identifies which organism is responsible for theinfection, this test is responsible for finding the source of the infection andto select a suitable treatment.
Non-biomedical based investigationBiomedical testing is not the only form of investigation apatient may undergo. There are various non-biomedical investigations.Point of care testingAnother form of investigation is point of care testing (POCT), this Idefined as diagnostic testing carried out outside the clinical laboratory, itcan be carried out near the bedside of the patient, at the time and place ofwhere the patient is receiving care.
POCT is usually carried out bynon-laboratory personnel, the results are used to determine treatment. Imagining techniques A diagnostic test is another type of investigation, which is carried out toconfirm the presence of a disease in a patient, this is done by recordingimages of the internal structure of the body to identify the presence orabsence of disease, foreign objects, and structural damage or irregularity. Thisis an imaging technique used to obtain diagnostic images of the inside of thebody for diagnosis. In medical radiographic testing, radiation is used to provideimages of the tissues, organs, bones, and vessels within the body. There are several imagingtechniques this includes X-ray radiography, ultrasound, computed tomography(CT) and magnetic resonance imaging. The detailed images provided by theseimaging techniques can be used to diagnose conditions including problems withblood flow, strokes and cancer. Using a CT scan also allows the location, sizeand shape of a tumour to be determined.
This type of investigation is also usedto monitor the condition, this means the size of the tumour can be checkedduring and after treatment.An MRI scanner is a large tubewhich consists of powerful magnets. During the scan the patient lies within thetube. An MRI scan may be used to examine nearly any part of the body. Theresults of the scan can be used to aid diagnosis of a condition, results canalso help in developing a plan for treatments.
Electrocardiogram (ECG) Test An electrocardiogram is a test that measures the electrical activity of theheart. The electrical activity of the heartbeat is measured. Each beat resultin an electrical impulse traveling through the heart. These electrical impulsespreads through the walls of the atria and cause them to contract, allowingblood to pump from the heart. A normal heartbeat on ECG displays timing of thetop and lower chambers. This test is carried out is to findout how long it takes for an electrical impulse to travel from part of theheart to the next, this shows if the electrical activity is regular or not,whether it is fast or slow. The amount of electrical activity that passes throughthe heart can be used to find out if sections of the heart are overworked. Theresults from this test are used to see any abnormal or unusual activity.
Different investigations usedto diagnose Liver cancerLiver function testsLiver function tests are the most important tests for liver cancer. Liverfunction tests help determine the health of the liver, this is done by measuringthe levels of proteins, liver enzymes or bilirubin in your blood. Liver function tests include alanine transaminase (ALT), aspartateaminotransferase (AST), alkaline phosphatase (ALP), albumin, and bilirubintests.
The ALT and AST tests are used to measure the enzymes the liver releasesin response to damage or disease. The albumin and bilirubin tests are used to measurethe livers ability to produce albumin, and the how well the liver disposes ofbilirubin. Liver function tests are very important, as problems with the livercan be life-threatening.UrinalysisUrine testing may be carried out if patient complains of kidney problems.Urine is collected in a container, which is then sent to a laboratory fortesting. Within the laboratory microscopic and chemical tests are performed onthe sample to look for traces of blood and other substances.
Urinalysis iscarried out in liver cancer as it can reveal evidence of diseases, including diseaseswhich have not yet presented any signs or symptoms. UltrasoundA liver ultrasound scan can also be used to diagnose liver cancer. Theultrasound scan uses sound waves to produce an image of the liver. The patientundergoing the test will be lying on their back, the ultrasonographer spreadsgel on the stomach area, a small handheld probe is moved over the area, thisproduces sound waves. The sound waves build up a picture of the liver. The ultrasoundimages can reveal any cancers growing in the liver. Liver Biopsy To confirm the diagnosis of liver cancer, a patient undergoes a tissuebiopsy.
During the liver biopsy, part of a mass in the liver is removed by asurgeon. This is done by passing a fine needle through the skin and taking asample of the mass. The sample is then sent to a laboratory where it isexamined under a microscope to determine if the cells present are cancerous. Computed tomography (CT)A CT scan can be performed on an individual’s abdomen to look for thepresence of cancer in the liver and elsewhere in that area. The scan can alsobe used to detect cancer elsewhere that could have spread to the liver, as wellas determine if the cancer started in the liver or formed in another part ofthe body and spread to the liver. A highly detailed picture of the internalorgans is produced by a CT scan, an X-ray machine rotates around the patient’sbody, the patient may be injected with a dye that helps create a clear image ofthe liver.