Your kidneys are responsible for removing waste products and excess fluid from your blood. How well they are doing their job can be measured by examining the levels of waste product in the blood as well as levels of electrolytes which regulate fluid in the body. Kidney disease has few symptoms in the early stages so it is important to monitor kidney function, especially if you are a diabetic, have raised blood pressure or a close relative with the disease.

Iron is an element that we require for several different bodily processes such as creating new red blood cells, carrying oxygen around the body and strengthening our immune system. Most of the iron in our bodies is found in haemoglobin, a protein in our red blood cells. A smaller proportion is stored in a protein called ferritin that is responsible for controlling the release of iron when levels are too low or high. Iron status tests measure the total amount of iron in the blood with a view to diagnosing anaemia or iron overload (haemochromatosis). They also test your body's ability to absorb iron as well as the amount of iron stored in your body.

Vitamins are essential nutrients that your body needs to function properly. You cannot make them yourself, so they need to come from the food you eat. Vitamins divide into two types: fat soluble and water soluble. Fat soluble vitamins, like vitamins A, D, E and K are found in oily foods, whether animal or plant-based. They are stored in the fatty tissue in your body as well as the liver, and therefore you don't need to eat them daily. Most water based vitamins like vitamin C are not stored in the body, and therefore you need to eat foods which contain them more frequently. You should get all the vitamins you need from a balanced diet. Sometimes, however, dietary choices or health problems can lead us to be deficient in some vitamins.

Creatine kinase (CK) is an important enzyme in tissues that have a fast metabolism, including muscle tissue. Sport and competitive training imposes substantial mechanical stresses on your body and one of the most prominent by-products of this is CK, which leaks into the blood when your muscle fibres are damaged from repeated, intense contractions. Traditionally in medicine, CK has been a marker of serious muscle injury due to a variety of mechanisms. High levels can be dangerous and can accumulate to cause a nasty condition called ‘rhabdomyolysis’. This is when so much muscle breaks down that the CK by-product can make you sick and even cause kidney failure and heart attack. However, for the athlete muscle breakdown is key to the anabolic process and so instead of breaking your muscle down by accident, you're breaking it down on purpose and as a result an athlete’s body adapts to deal with far higher levels of CK than the average person. An understanding of healthy CK levels is important as it can give measures of capacity for increased training load or flags about over-training and need to reduce load. If you are a muscle building athlete and your CK level is on the low side of the normal range, then technically you can increase your workload for faster, larger gains in performance without overloading your system (from a CK point of view!). If you CK level is too high then it’s an important alarm bell to reduce your training load to prevent severe muscle injury, overtraining syndrome and possibly kidney damage. To make sure you get the right result always ensure you test your CK level at least 2 days post-heavy exercise to get your baseline.

Inflammation occurs when your defence system is activated to rid your body of foreign invaders or irritants and to protect against tissue damage. Typical signs of inflammation include heat, redness, swelling and pain. Inflammation can be acute or chronic. Acute inflammation is often caused by infection or injury, and it flares up and disappears within days. Chronic inflammation is caused by longer-term conditions such as arthritis, inflammatory bowel disease or asthma. Inflammation causes levels of certain proteins in the blood to rise and these can be measured to assess the extent of inflammation as well as in some instances the cause.

Hormones govern every activity of your body, from growth and metabolism to reproduction and your sleep cycle. Even a small imbalance in your hormone levels can have a significant impact on your health, affecting your mood and energy levels as well as fertility and libido. Hormones are known as chemical messengers which are manufactured in your glands and released into your bloodstream. They instruct your body in everything it does – regulating appetite, growth, mood and reproduction. Generally they keep the body functioning and in balance. Hormone disorders are common and can often be put right through hormone replacement therapy or lifestyle changes. Hormone levels fluctuate throughout the day and also, for women, through the reproductive cycle.

Type 2 diabetes is a metabolic disease which is becoming increasingly common across all ages. Up to one third of adults in the UK have prediabetes and are at risk of developing diabetes. It is caused by the interplay between lifestyle factors and our genes. Lack of exercise, making unhealthy diet choices and being overweight all increase the likelihood of developing diabetes. It is important to identify diabetes early; if you have raised blood glucose and are at the stage described as prediabetic, then you can still bring blood glucose levels back down by making lifestyle changes. Once diabetes is diagnosed it is vitally important to manage your blood glucose levels carefully to avoid many of the devastating side-effects of the disease which can damage nerves, blood vessels, kidneys and eyes. Diabetes is a known risk factor for cardiovascular disease as well as some cancers and is a major cause of decreased life-expectancy.

Your thyroid is a gland in the front of your neck which produces hormones which help to govern your metabolism. It is possible for your thyroid to under-produce or over-produce thyroid hormones, and both conditions can lead to debilitating symptoms. Typically an underactive thyroid leads to symptoms of lethargy, weight gain and dry skin and hair while an overactive thyroid leads to symptoms of feeling nervous and anxious, as well as weight loss. Once diagnosed, thyroid conditions can be treated but even then it is important to continue to monitor levels of thyroid hormones to ensure that your levels remain optimal.

Gout is a form of arthritis which occurs mostly in the joints of the fingers and toes, wrists and ankles. It is caused by excess uric acid accumulating and depositing crystals in the joints. The first attack often affects the big toe which becomes so inflamed and painful that a sufferer cannot bear anything to touch it. Gout can affect one or more joints at the same time. Treatments for gout include steroids, non steroidal anti-inflammatories and colchicine.

Your clotting cells (platelets) are produced in the bone marrow and are important for controlling bleeding. Sometimes too few platelets are produced or are destroyed too quickly resulting in a condition known as thrombocytopenia. This can be caused by immune disorders, some medication, liver disease or chronic bleeding. A high platelet count is called thrombocytosis and can be caused by a variety of conditions including bone marrow disorders, infection and inflammation.

Red blood cells are the most common type of blood cell and have the job of delivering oxygen to your tissues via your circulatory system. Red blood cells are continuously created in your bone marrow to replace cells which are lost through bleeding or cell ageing. Your red cell count should be stable, but certain conditions can cause too few or too many cells to be created, cells to die too quickly or to be misshapen. If you are not producing enough red blood cells it affects the amount of oxygen being delivered to your tissues, resulting in anaemia and its associated symptoms of fatigue and pale skin. Overproduction of red blood cells can cause headaches, blurred vision and an enlarged spleen.

Your white blood cells are the key to your body's immune or defence system. They fight infections and protect your body from foreign particles such as harmful germs and bacteria. White blood cells are formed from the stem cell of the bone marrow and have a lifespan of a few days. There are five major types of white blood cell and they all play a different role in protecting the body. The numbers of each one of these types of white blood cell give important information about your immune system as well as in the diagnosis of recent infection.

Minerals are inorganic substances that your body needs for normal functioning. Minerals can be divided into two categories; minerals and trace elements. Both are as important as each other, but minerals are required in higher amounts than trace elements. Your body cannot make minerals, so minerals must come from the food you eat. Minerals are responsible or many bodily functions including the formation of strong bones and teeth, regulating the body's fluid balance, healthy nerve and muscle function as well as hormone production and blood pressure regulation. We should get most of the minerals we need through our diets. However, if you avoid certain food groups, eat a very restricted diet or have an absorption problem in the gut, you may find that you are deficient in some minerals.