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Being told that you need to have a strange test or one with some peculiar abbreviation can be rather worrying. It is always a good idea to discuss with your doctor what any test is for and what is involved in having it done. Investigations such as ECGs and blood tests have been around for ages. However, some of the endoscopic and imaging techniques have only recently become available. 

Here are some investigations that could be recommended by your GP or specialist: 

Ambulatory BP monitoring  is being increasingly used to give a more accurate assessment of blood pressure. The person wears a small blood pressure unit on the waist for 24-hours and goes about all the usual activities of the day. A cuff around the arm inflates and deflates automatically every 30 minutes, recording the pressure at these intervals. It is very useful in the diagnosis of white-coat hypertension where the blood pressure may be abnormally elevated at the doctor's surgery and quite normal at other times. It can also be helpful when blood pressure readings have been just above the normal range and a decision has to be made about whether long-term medication is required. 

A biopsy is a procedure whereby a specimen of tissue is obtained for inspection under the microscope and more precise diagnosis. This could be the excision of a skin mole to exclude a melanoma, or the removal of a piece of breast tissue to rule out a breast cancer. These days biopsies can be taken from virtually every organ. Any tissue that is removed is sent to pathology for a detailed examination and report.

An ECG (electrocardiograph) is a tracing of the electrical activity of the heart. Leads are connected to the patient's wrists, ankles and chest by small stick-on patches or suction caps. There is no discomfort and the test takes only minutes to perform. It can be done at the doctor's surgery, in the home or at the local pathology centre. The ECG is very useful in detecting signs of a heart attack as well as other cardiac conditions. In a hospital or ambulance situation certain leads of the ECG are continuously monitored on a screen. An ECG performed on a treadmill or under other exercise conditions can be a useful test for angina, especially in men. This is called an exercise ECG or stress test. Sometimes an ECG is normal at rest but becomes quite abnormal with exercise. This always requires further cardiological assessment. 

A Holter monitor is an ambulatory 24-hour ECG tracing that specifically checks for abnormal heart rhythms. The person having the test is able to walk around wearing a small ECG unit that gives a continuous tracing. The results are analysed by computer and then reported on by a cardiologist. 

An EEG (electroencephalograph) is an important investigation for epilepsy. Electrodes are applied to the scalp with an adhesive gel and the electrical activity of the brain is recorded on graph paper. The test causes no discomfort and can be a useful investigation for other brain disorders. 

Endoscopic examination involve having a look inside an organ or cavity with a tiny fibreoptic light-source on the end of a flexible tube. The degree of refinement in these tests in recent years has been astonishing. 

Some of the areas examined are the stomach (gastroscopy), bowel (colonoscopy), abdomen (laparoscopy), bladder (cystoscopy), lower bowel (sigmoidoscopy), uterus (hysteroscopy), pelvis (pelvoscopy), and joints (arthroscopy). These highly-specialised investigations have the great advantage of allowing a biopsy to be taken if necessary. With techniques such as laparoscopy, arthroscopy and hysteroscopy, various types of operations can also be performed. An anaesthetic is required for these procedures. 

The most common endoscopic investigations requested in general practice are gastroscopies and colonoscopies. Fasting is required for both tests and a thorough laxative emptying of the bowel is necessary prior to a colonoscopy. An intravenous injection is given to make the person relaxed and sleepy. Most people have very little recollection of having the test done. Because there may be some mild drowsiness it is necessary to wait for an hour or so and then be driven home afterwards. A detailed report for the referring doctor is usually handed to the patient on leaving. 

Flexible sigmoidoscopy is a newer procedure that is being performed more commonly these days. It is ideal when an inspection of only the lower part of the large bowel is required. It has several advantages over colonoscopy: less preparation, no sedation and taking a much shorter time. This investigation is only now becoming more generally available. Standard sigmoidoscopies have been done for many years and are performed by specialists and some GPs in their consulting rooms. Although not as extensive an examination as flexible sigmoidoscopy, it is a very useful procedure for looking at the lower part of the bowel. 

MRI (magnetic resonance imaging) is a comparatively new imaging technique that gives exceptional detail of structures such as the brain and spinal cord. It is not an X-ray. The part of the body being investigated is positioned inside a magnetic field. Different types of tissue emit different radio signals and an image is able to be generated by computer on to a screen. The tests take a little longer than other imaging techniques and the person has to be quite still. For this reason some people can a feel a little confined while the test is being performed. MRI is very safe but still quite expensive, and usually only available in some larger centres. 

Nuclear scans are another important imaging technique. They involve the injection of radioactive tracer materials that are preferentially picked up by organs such as the thyroid gland, heart and bone. Scans help to identify areas of abnormal activity that might be due to conditions such as tissue damage, tumour or infection. They are very safe and have been performed for many years. 

Respiratory function tests may be advised to assess whether there is evidence of a chronic lung problem like emphysema or a reversible condition such as asthma. The person being tested is asked to blow into a tube that is connected to a measuring device. Details such as the volume of air that is breathed out and the flow rate are recorded. The test might be repeated after a dose of medication such as Ventolin to see if there has been any alteration in the readings. There is a whole range of other tests that can be performed and they are interpreted by a respiratory specialist. 

Sputum tests may be requested to check which bacteria are responsible for a chest infection or pneumonia. Specimens are coughed up into a sterile jar and forwarded to the microbiology department of the pathology centre. The sputum is examined under the microscope and then put on to special culture media to see whether any bacteria grow. Special staining techniques can be done to check for TB. Specimens of sputum can also be examined to see whether there is evidence of cancer cells. 

Stools or faeces, are also checked for a number of conditions. In cases of diarrhoea that might be due to a bowel infection, fresh stool specimens are collected at home and taken over three consecutive days to the pathology centre. A variety of organisms can be responsible for bowel infections. Microscopy and culture of the specimens may help the doctor decide whether medication is required. Stools are also tested as part of screening for early bowel cancer, especially in those with a family history. The test is sensitive to very small amounts of blood and is also performed over three consecutive days. If positive, other investigations such as colonoscopy are required. 

Swabs are taken from a variety of sites including the throat, urethra, vagina, anal canal and a discharging wound or abscess. A sterile cotton bud is carefully inserted into the area and a specimen collected. This is put into a plastic tube which contains culture medium to keep organisms viable until the specimen reaches the laboratory. Having a swab taken usually causes minimal discomfort. At the laboratory the specimen is viewed under the microscope and cultured to see if any infective organisms are present. 

Ultrasound tests depend on sound waves being reflected off organs and tissues and an image being produced on a video screen. It is essentially a non-invasive technique and has been used in obstetrics for many years to assess foetal size, development and the presence of certain abnormalities. Ultrasound is a useful test for abdominal conditions like gallstones and can give good detail of other internal structures. It can demonstrate whether a clot has occurred in a major leg vein. It can also help to clarify the nature of breast cysts that might have shown up on a mammogram. 

Echocardiograms or cardiac ultrasounds give a great deal of information about the heart, particularly in relation to valve problems and signs of heart enlargement. 

Doppler studies apply ultrasound techniques to the study of blood flow. Duplex scans are a further refinement and allow for colour pictures of the blood flow in major blood vessels. They are extensively used to assess the degree of narrowing in neck and leg arteries. 

New smaller ultrasound probes allow for the diagnosis of soft tissue injuries such as torn tendons around the shoulder. Vaginal and transrectal probes are also being used to evaluate ovarian and prostate problems. 

Urine tests are frequently done at the doctor's surgery as part of a general check. They are usually just simple dipstick tests to see whether there is any protein, blood or sugar in the urine. They are done on ordinary urine specimens and take only seconds to read. 

A midstream urine is performed to establish whether there is an infection in the urinary tract. It is very important that the specimen be free of contamination. The urinary opening is first wiped with a sterile towelette and in females the labia separated. The first part of the stream is ignored and then a sample caught midstream in a sterile plastic jar. A screw-top cap is applied and the specimen sent to the pathology centre, for microscopy and culture. 

Because it is not possible to obtain a midstream specimen from a baby or infant, an adhesive paediatric urine collector bag can be used as an alternative. Although these specimens are more likely to become contaminated, they are helpful if they demonstrate that no infection is present. 

If a reliable urine specimen is unable to be collected by any of these methods a paediatrician may advise doing a direct aspiration of urine from the bladder. This is done by inserting a fine needle above the pubic bone. In experienced hands this is a very straightforward procedure and the specimen is sent to the laboratory in the usual way. 

X-ray investigations have been greatly refined in recent years. However, the plain X-ray is still the preferred initial investigation for chest conditions, and for bone and joint problems such as fractures and arthritis. 

Angiograms are special X-rays that show the precise anatomy and flow of blood in arteries. A tiny tube called a catheter is inserted into the main groin artery and then threaded along to the area being examined. Non-ionic radio-opaque dye is injected for contrast and the pattern of flow is observed on a screen and recorded. These days the incidence of adverse reactions to contrast media is exceedingly uncommon. 

Angiograms are recommended by a specialist when some form of arterial surgery is being considered. Their main use is in the assessment of the coronary arteries, neck arteries and major arteries in the legs. 

Barium studies have long been used to give an image or outline of internal structures such as the stomach and the bowel. A metallic salt called barium sulfate can be mixed into a suspension and will show up on X-ray. It can be ingested as a meal or administered into the rectum as an enema. A barium meal will demonstrate the oesophagus or food pipe, the stomach and the duodenum, or beginning of the small bowel. A barium enema will give a picture of the large bowel. 

Although barium studies are very useful, endoscopic examinations like gastroscopy and sigmoidoscopy/colonoscopy are preferred these days for the investigation of symptoms such as indigestion and bleeding from the bowel. 

Bone densitometry studies utilise a variety of X-ray techniques to look at the internal structure of bone and actually measure its density. As well as assessing the risk of osteoporosis these studies are also able to measure the response to treatment. 

CT scans (Computerized tomography)  have been greatly improved over the years. A whole series of X-rays are taken in slices through several planes, and the images are enhanced by computer. CT scans now take only minutes to perform and, unlike plain X-rays, give very clear pictures of the contents of the abdomen and chest. A CT abdomen, for example, may pick up a group of enlarged lymph glands that would otherwise not be visible. CTs also give good detail of the brain to detect problems such as strokes and tumours, and the spine for conditions like disc protrusions. Sometimes an injection of contrast medium is required to improve the clarity of the images. The total amount of radiation exposure with a CT scan is very small, about the same as with three or four chest X-rays.

An IVP ( Intravenous pyelogram) is still the best initial investigation for conditions such as kidney stones and recurrent urinary infections in adult patients. The test involves the injection of non-ionic contrast into a vein and taking several X-rays of the kidneys and drainage system at regular intervals. During the procedure a firm band is applied around the abdomen to delay the emptying of contrast and provide the clearest pictures.

Mammograms are X-rays of the breasts. They are an excellent screening test for women between the age of 50 and 75 years. However they are not infallible. Any breast lump that persists should always be thoroughly investigated. This may involve fine needle biopsy or removal of the lump for pathology, regardless of whether there has been a recent normal mammogram.

Medical technology has brought about an amazing refinement in the quality of the investigations that are now available. As a result the management of so many illnesses has been vastly improved. However, all investigations cost money and have a certain safety consideration. They should only be performed when the result of the test will have a clear bearing on the patient's further treatment.


 Dr. Andrew Pattison: Common Consultations
North East Valley Division General Practice, Melbourne, Australia.   Disclaimer
  - Last modified: August 18, 2001