Over 500 million pathology tests were ordered for Australians in the last 12 months, covering a vast array of diseases and conditions from cholesterol checks to cancer diagnoses. But what are some of the most common pathology tests we’re having performed and what are they actually looking for?
Liver Function Tests
The Liver Function Tests (LFT) are a group of blood tests that measure some enzymes, proteins, and substances that are produced or excreted by the liver. The amounts of these substances in the blood can be affected by liver injury. When performed together, these tests give the doctor a snapshot of the health of the liver and can provide a starting place for any further diagnostic testing.
There are many diseases, infections and lifestyle factors that can cause damage to the liver and, given a significant amount of liver damage may be present before symptoms appear, pathology is key to early diagnosis and effective treatment.
Full Blood Examination
The full blood examination (FBE), also known as the Full Blood Count (FBC blood test) or Complete Blood Count (CBC), provides important information about the numbers and correct development of cells in the blood: red blood cells that carry oxygen, white blood cells that fight infection and platelets that help blood to clot.
Abnormalities in any of these can tell us a lot about a range of important conditions including some nutritional factors, medications and, occasionally, exposure to toxic substances. Abnormalities in the FBE blood test can be caused by anaemia, infections, some blood cancers such as leukaemias and some inherited conditions.
As the name suggests, an iron studies test is a pathology test performed if your doctor suspects that you have too little or too much iron in your system.
Iron is needed to help form adequate numbers of normal red blood cells, which carry oxygen throughout the body. Low iron levels can lead to anaemia, in which the body does not have enough red blood cells leading to easy fatigue and lack of energy. Iron deficiency is a reflection of poor dietary intake, poor absorption or excessive loss of iron through bleeding, so it is vitally important to find the cause of iron deficiency as it may indicate important underlying diseases.
Too much iron in your blood – known as iron overload or haemochromatosis – increases the risk of a number of serious conditions including liver disease, heart failure, arthritis and diabetes. Iron overload is asymptomatic until tissue damage starts to occur; damage which can be prevented by early diagnosis.
The effects of too much or too little iron are readily treatable, especially if detected early, making pathology tests important in this condition.
TSH (Thyroid Stimulating Hormone) Quantification
As part of the Thyroid Function Test, this blood test is performed to screen, diagnose and monitor treatment for thyroid disorders such as hypothyroidism (not enough thyroid hormone) or hyperthyroidism (too much thyroid hormone). These disorders can occur spontaneously or as a result of tumours, pregnancy, infections and sometimes medications.
The test measures the amount of thyroid-stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and acts as a ‘messenger’, telling the thyroid gland to start making hormones. In patients with a thyroid or pituitary disease the messaging system gets unbalanced.
Thyroid hormones regulate a range of vital bodily functions including breathing, heart rate and body weight, temperature and general energy levels, so it is essential that they are produced at the correct levels.
A urinalysis is a test performed on a sample of urine to look for some metabolic disorders (such as diabetes) and kidney disorders. A patient may be referred for urinalysis by their doctor in a range of scenarios. Common tests as part of urinalysis include testing for urine protein, for example during pregnancy, red cells for example with kidney disease, and also markers of infections of the urinary tract.
INR (International Normalized Ratio)
This pathology test is used to check how well the clot-preventing medication, warfarin, is working. People with heart conditions, such as an irregular heartbeat, or after replacement of a heart valve, may need to take this medication to prevent stroke. Other people may use warfarin to treat a current clot or reduce the risk of developing a clot in legs or lungs during periods of risk, such as surgery.
The test measures how long it takes someone on warfarin to convert one protein (prothrombin) to another (thrombin) compared to someone not on this drug. This chemical reaction is vital to clot formation. Patients on warfarin need to have the test performed regularly to monitor the drug‘s effectiveness and to allow the patient’s doctor to adjust dosage levels accordingly. Levels are affected by diet, medications and changes in general health. High levels may produce no symptoms but increase the risk of spontaneous bleeding.