Introduction to Pathology

Published September 14th, 2010  |  Last updated June 3rd, 2014

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 diagnosisThe process of determining which condition a patient may have..

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 HIVThe abbreviation for human immunodeficiency virus, which is the cause of AIDS. 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 pregnancythe period from conception to birth testing through to cholesterolA 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.. 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, sodiumOne of the chemical components of salt (sodium chloride) and an important blood chemical., potassiumAn element that is one of the main ions, or charged atoms, of intracellular fluid, and is also important in nerve and muscle function. etc) – requires coagulated bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid.
  • Haematology tests (e.g. haemoglobinThe oxygen carrying pigment that is present in red blood cells., white blood cells) – requires whole blood
  • Microbiology tests (e.g. strep sore throat) – may require a swabAbsorbent 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
  • Virology tests (e.g. hepatitisInflammation to the liver with accompanying damage to liver cells., measlesAn infection of the respiratory system caused by a virus., 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 vitaminEssential substances that cannot be produced by the body and so must be acquired from the diet. levels, allergyVarious conditions caused by exaggerated reactions of the immune system (hypersensitivity reactions) to a variety of substances. markers, auto-immune disease, rare disorders, hormones, drugs to tumour markersSubstances released by various tumours that may be detected in the blood. 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 antiviralA substance that acts against viruses, for example and antiviral drug. 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.

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