Introduction to Pathology

Pathology, according to The Royal College of Pathologists is; “the hidden science that every day saves lives by helping doctors to make the right decisions.”

As Dr Nigel Kellow points out in his excellent ‘Pain Management’ article, there are laboratory tests for pretty well every known substance in the body. These substances are normally either supposed to be present, or depending on amount mark a certain pathological (disease) state. As a result, laboratory testing combined with symptoms is the traditional first step to making a medical diagnosis.

Historically, due to the technical complexity of the tests themselves and the need to understand what is and isn’t ‘normal’, these tests have been the strict domain of doctors to control and request on behalf of their patients. However, this situation is now changing. For example, there are government initiatives to encourage people to come forward to be tested for HIV and / or Chlamydia. Why? - Because a rapid diagnosis will allow you to be treated quickly and help prevent further spread of the disease. 

Even ten years ago, many of these tests were laborious and time consuming to perform in specialist laboratories, but the technology has now changed to the extent that many pharmacies now sell self-testing kits - anything from pregnancy testing through to cholesterol. It is still relatively early days and there are sometimes problems associated with these kits. It is therefore still generally recommended to be tested professionally using an accredited laboratory.

The technology is improving rapidly and soon everyone will be able to place something as simple as a saliva sample on a test strip that feeds into an accessory on a PC. Add in information on your symptoms and family history and the technology will almost remove the need for a doctor. However, we are not there yet and different tests require different types of sample, for example:

  • Biochemistry tests (e.g. Cholesterol, sodium, potassium etc) – requires coagulated blood
  • Haematology tests (e.g. haemoglobin, white blood cells) – requires whole blood
  • Microbiology tests (e.g. strep sore throat) – may require a swab
  • Virology tests (e.g. hepatitis, measles, HIV) – may require saliva or a blood sample.

There is practically nothing you cannot be tested for.

In a new era of ‘patient choice’ you can either test yourself using a kit from the pharmacy, or you can send a sample to the laboratory to have a full set of profiles, and you can have anything tested from nutritional and vitamin levels, allergy markers, auto-immune disease, rare disorders, hormones, drugs to tumour markers. There is a test for pretty well everything.

You can check either your status at any one point in time, or you can monitor change over time. For example, you can check to see if the antiviral drugs are working or you might want to see if a healthier lifestyle is actually improving your lipid levels.

So why are we not testing ourselves?

The prime reason is cost. The price of a single test can vary from a penny to hundreds of pounds. There are other reasons too ranging from trying to determine an abnormal result against a ‘normal range’ through to the more psychological implications.

Normal Range

With all the publicity and advertising around healthy diets, if you were to ask someone – is cholesterol good for you? You might be surprised by the range of answers you get. Of course, cholesterol is pretty essential for life, but elevated cholesterol levels could indicate an underlying disease state (depending on the type of cholesterol – HDL and LDL). If you measure cholesterol in a thousand people you can produce a statistical range and find the average, from this you can find the ‘normal range’. However, this is a slightly precarious assumption, because what is ‘normal’ in one person may not be for another. Therefore, ‘normal ranges’ can only really be used for guidance and comparison.

Psychological Implications

The implications are potentially far reaching. Discovering you are pregnant could either be an absolute joy, or a concern. Equally, professional counselling is strongly advised in association with some tests, such as HIV.

But the point is that if you want to be tested for anything – you can, and knowing your own profile (even if it is just blood type) and understanding some basic pathology is fundamental to understanding the state of your own health.

Various conditions caused by exaggerated reactions of the immune system (hypersensitivity reactions) to a variety of substances. Full medical glossary
A substance that acts against viruses, for example and antiviral drug. Full medical glossary
A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
The basic unit of all living organisms. Full medical glossary
A substance present in many tissues and an important constituent of cell membranes although high concentrations of a certain type of cholesterol in the blood are unhealthy. Full medical glossary
The process of determining which condition a patient may have. Full medical glossary
The basic unit of genetic material carried on chromosomes. Full medical glossary
The oxygen carrying pigment that is present in red blood cells. Full medical glossary
Inflammation to the liver with accompanying damage to liver cells. Full medical glossary
The abbreviation for human immunodeficiency virus, which is the cause of AIDS. Full medical glossary
A substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. Full medical glossary
An infection of the respiratory system caused by a virus. Full medical glossary
An element that is one of the main ions, or charged atoms, of intracellular fluid, and is also important in nerve and muscle function. Full medical glossary
the period from conception to birth Full medical glossary
One of the chemical components of salt (sodium chloride) and an important blood chemical. Full medical glossary
Absorbent material used to mop up bodily fluids, such as blood, for instance during an operation, or to take a sample for laboratory analysis. The term may also be used as a verb to mean the action of taking a swab Full medical glossary
An abnormal swelling. Full medical glossary
Essential substances that cannot be produced by the body and so must be acquired from the diet. Full medical glossary
A type of blood cell that protects the body against foreign substances and produces antibodies. Full medical glossary