The Role of The Medical Laboratory.

You are suffering from diarrhea and excruciating abdominal pain. You visit your local general practitioner (GP), clinic, or hospital. You explain the problem to the doctor and he/she collects blood and fecal samples from you.

Why are they collecting your feces and blood? Where do they send those samples? What are they going to do to your specimens? Who is going to do what to your samples? Are they the nurses? Are they the doctors?

Many people ask these questions whenever they or their loved ones get ill and they go to the hospital and the doctors and nurses collect some specimens from them including blood, urine, feces, sputum, pus, or cerebral spinal fluid.

The samples go to the medical laboratories to be examined by biomedical scientists.

In the medical laboratory, there are biomedical scientists who do the scientific tests on your specimens, there are medical laboratory assistants who assist biomedical scientists and there are also clinical scientists who advise medical doctors and nurses on laboratory tests to order and also explain the meaning of the results to doctors and nurses.

Biomedical scientists and clinical scientists are educated to degree level and some of them have got masters degrees and PhDs.

After they finish university education, they undergo some professional training before they can be allowed to practice as professionals.

In the United Kingdom, all practising biomedical scientists must be registered with the Health and Care Professions Council.

Medical laboratories fall under the Directorate of Laboratory Medicine or the Directorate of Clinical Pathology. There are many laboratory departments and they include Clinical Biochemistry, Haematology, Blood Transfusion, Immunology, Medical Microbiology, Histology.

Medical laboratories perform tests and investigations that help in the diagnosis, screening, monitoring, management, and treatment of diseases.

Clinical Biochemistry:

In many hospitals, the clinical biochemistry department is divided into (a) Autolab where general chemistries are done on fully automated analyzers; (b) Specialist biochemistry which does specialized tests not done at other smaller hospitals; © Toxicology where tests like drug abuse substances, for example, opiates, amphetamines, cannabis, and many others are done.

Most of the samples tested in the clinical biochemistry laboratory are blood, but they also do tests on feces (e.g fecal occult blood, fecal elastase, fecal fats.), cerebral spinal fluids, urines and plural, ascetic and drain fluids.

Some of the tests done are liver function tests, thyroid function tests, glucose, urea and electrolytes, bone profile, vitamin D profile, troponin, therapeutic drug monitoring and many others.


In hematology, they do tests that help in the diagnosis, monitoring, and treatment of diseases such as leukemia, lymphoma, anemia, and many other diseases that affect the blood. They perform tests on blood samples and some of the tests they do are Full blood count (FBC) in which they count the number of different components of blood per liter, for example, platelets, white blood cells, red blood cells, etc.; clotting screen and blood film examination.

Blood Transfusion:

If you are involved in an accident and you need blood, the biomedical scientists in blood transfusion will test your blood to find out which blood from donors matches yours by testing your blood group and doing crossmatch. This is done so that you can be transfused with blood which won’t be rejected by your body through transfusion reactions which may be fatal.

Medical Microbiology:

The medical microbiology department is divided into bacteriology, virology, parasitology, and mycology. In bacteriology, they test your feces, blood, pus, or sputum for bacteria that cause disease. After finding them, they identify them and then do sensitivity tests to find out which type of antibiotic can kill that bacterial strain so that you can be treated using that antibiotic.

In virology, they do tests for viruses, for example, HIV tests, tests for hepatitis A, hepatitis B, hepatitis C. In parasitology, they test for parasites, for example, Trichomonas vaginalis, Plasmodium falciparum, bilharzia, and many others. Mycology is the branch of microbiology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source for tinder, medicine, food, and entheogens, as well as their dangers, such as toxicity or infection. Examples are athletes’ foot, tinea pedis, tinea capitis.


Histology or histopathology is where biomedical scientists perform microscopic studies of diseased tissues. These investigations help in the diagnosis, monitoring, and treatment of many types of cancers.


Immunology is where they do investigations on the human immune system. Some of the tests they do are immunoglobulins (IgM, IgG, IgA), complement (C3, C4) and many others.

Due to advancements in technology, most of the analyzers in clinical biochemistry can now do serology tests done in virology and in immunology. This is leading to the disappearance of the virology and immunology departments in many hospitals.


It is very important that when the doctors and nurses want to collect your blood, feces, urine, pus, mucus, aspirate or sputum for laboratory testing you give consent because these tests help in the diagnosis, screening, monitoring, management, and treatment of diseases and are also done by highly educated and trained personnel. They may save your life.


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