Here I was, fiddling around with an idea for my next Science Page, when I had a flash of inspiration. You all know that I work in a pathology laboratory, and yet I’ve never done an article solely on pathology. So, for the benefit of all those who want an answer – including my children – here it is:

Pathology: The science of bodily diseases
The Oxford English Reference Dictionary, 2nd Ed.

So, you’re feeling unwell? Time to see the doctor? So, you make an appointment and the poor GP finds your symptoms could be explained by a number of diseases. So your doctor sends you off for some tests.

What sort of tests could they be?
If you appear to have a urinary tract infection, you will be asked to supply a random urine…which means the urine can be collected at any time of the day, but a midstream sample is best. If your doctor suspects something more, he might ask for a sample from first thing in the morning, or for a 24 hour collection.

If you are suffering from bowel problems, your doctor may request of faecal sample. These are usually random collections, but rarely they may require a samples over three days.

Then, if you are coughing a lot, and some sort of chest or nasal infection is suspected, you may be required to supply a sputum sample. These samples are often the hardest to collect, as most people can’t cough on command.

If you have a rash, unexplained blisters, a septic wound, or just some sort of weeping fluid from any orifice - such as an ear infection - a swab for microbiological sensitivity & culture, or a fungal card may be collected. The most common cause of a rash is allergies, and so a prick test may be required, where the scientist or pathologist will scratch your skin with a series of allergy triggers; if you so have a reaction, you will discover what may be causing the rash.

If you have a mole that’s changed shape and colour, a tissue sample will be required for histology. Often, tissue samples will be collected during surgery, or other invasive proceedure, such as a colonoscopy.

Then again, the most common test might be required: a blood test. Your blood is even more unique than your fingerprint, and it can not only identify you, but it can also help identify any diseases you may be suffering from, be they environmental, congenital, viral, bacterial or genetic. Examples of a viral disease would be cytomegalovirus or Ross River fever, while a genetic disease could be something like Down’s syndrome, and an example of a congenital problem is Coeliac disease. If you are suffering from heavy metal poisoning, that disease is caused by an environmental contaminant. You can be tested for high cholesterol, blood sugar levels, low iron: just about anything. A disease will leave some trace, direct or subtle, in your blood.

If you have had your blood collected, you may notice that there are a variety of tubes, for there are different tubes used depending on how the blood is handled in the lab. There is the septum type, with the substance down the bottom, this substance is to separate the cells and the serum after spinning the blood down to produce the blood serum. There are whole blood tubes, clot tubes, tubes with lithium heparin added, etc.

Once the samples are taken, they are sent to a pathology laboratory for testing. Most tests are run through a series of specially-designed machines, but humans are still the best detectors of abnormalities, and there are still tests that can only be run by humans. And only humans can interpret the tests. A machine may be able to tell you the level of triglycerides in your blood, and may even be programmed to notify someone if the level is out of the normal range, but only a human being can tell you why, and what to do about it. As well, even though there are machines that can count the number of malformed cells in a cytology sample, the machine can only give the probability of a problem occurrence, you still need a person to eyeball the slide and see how the cells are disease.