Medical Tests & Procedures

Medical Tests & Procedures Articles

Oxygen Saturation Test

Your red blood cells carry oxygen through your arteries to all of your internal organs. They must carry enough oxygen to keep you alive. Normally, when red blood cells pass through the lungs, 95%-100% of them are loaded, or "saturated," with oxygen. If you have lung disease or other types of medical conditions, fewer of your red blood cells may be carrying their usual load of oxygen, and your oxygen saturation might be lower than 95%.  If your blood oxygen saturation is too low, you may need to be given oxygen to breathe. There is no preparation necessary. An estimate of your oxygen saturation can be made easily and painlessly with a clip that fits on your finger. This clip shines a light through one side of your finger; a detector measures the light that comes through the other side. This machine can make a good estimate of your oxygen saturation because blood cells that are saturated with oxygen absorb and reflect light differently than those that are not. Blood cells are a bright red when they are loaded with oxygen, and they change to a bluish color when they are no longer carrying a full load of oxygen. The finger clip machine cannot give a perfect measurement of your oxygen saturation; it can give only a rough estimate, and its measurement can be affected by things as simple as red nail polish on your finger. (Locked) More »

Pelvic Ultrasound and Transvaginal Ultrasound

Ultrasound uses sound waves instead of radiation to generate snapshots or moving pictures of structures inside the body. A radiologist or ultrasound technician applies lubricant to your skin to reduce friction. He or she then places an ultrasound transducer, which looks like a microphone, on your skin and moves it back and forth to get the right view. The transducer sends sound waves into your body and picks up the echoes of the sound waves as they bounce off internal organs and tissue. A computer transforms these echoes into an image that is displayed on a screen. Pelvic organ ultrasound is used to monitor pregnancy, find cysts on your ovaries, examine the lining of your uterus, look for causes of infertility, and find cancers or benign tumors in the pelvic region. Depending on the view needed, the ultrasound sensor is placed either on your abdomen (pelvic ultrasound) or in your vagina (transvaginal ultrasound). Your doctor might ask you to drink a few glasses of water before the test because a full bladder lifts your intestines out of the way and provides a clearer view of your pelvic organs. If you're having a transvaginal ultrasound and have a tampon in place, you'll need to remove it before the test. (Locked) More »

Percutaneous Transhepatic Cholangiography (PTCA)

Percutaneous transhepatic cholangiography is an x-ray test that can help show whether there is a blockage in the liver or the bile ducts that drain it. Since the liver and its drainage system do not normally show up on x-rays, the doctor doing the x-ray needs to inject a special dye directly into the drainage system of the liver. This dye, which is visible on x-rays, should then spread out to fill the whole drainage system. If it does not, that means there is a blockage. This type of blockage might result from a gallstone or a cancer in the liver. Tell your doctor if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist's office, or to x-ray dye. Also tell your doctor if you could be pregnant, since x-rays can harm the developing baby. If you have diabetes and take insulin, discuss this with your doctor before the test. Most people need to have a blood test done some time before the procedure, to make sure they are not at high risk for bleeding complications. If you take aspirin, nonsteroidal anti-inflammatory drugs, vitamin E or other medicines that affect blood clotting, talk with your doctor. It may be necessary to stop or adjust the dose of these medicines before your test. (Locked) More »

Pleural Fluid Sampling (or Thoracentesis)

Some infections and diseases cause fluid to accumulate in the space between the lung and the rib cage or between the lung and the diaphragm. This collection of fluid is called a pleural effusion. A pleural effusion might be detected on a chest x-ray. Sampling this fluid is important because it enables doctors to understand what caused the fluid to collect and how to treat the problem. The fluid can be sampled with a needle. You will need to sign a consent form giving your doctor permission to perform this test. Some patients have this test done in a doctor's office, while others are admitted to the hospital for it. Generally your doctor will decide whether you need to be in the hospital based on your medical condition. A chest x-ray or an ultrasound is done before the procedure. Tell your doctor if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist's office. If you take aspirin, nonsteroidal anti-inflammatory drugs, or other medicines that affect blood clotting, talk with your doctor. It may be necessary to stop or adjust the dose of these medicines before your test. (Locked) More »

Radionuclide Scanning

A radionuclide scan is an imaging technique that uses a small dose of a radioactive chemical (isotope) called a tracer that can detect cancer, trauma, infection or other disorders. In a radionuclide scan, the tracer either is injected into a vein or swallowed. Once the tracer enters the body, it travels through the bloodstream to the organ being targeted, such as the thyroid, heart or bones. Different tracers tend to collect in different organs. The tracer emits gamma rays, which are similar to X-rays. These gamma rays are detected by a gamma camera and analyzed by a computer to form an image of the target organ. Sites of potential problems send out more intense gamma rays and appear as bright spots on the scan. Types of radionuclide scans include PET scans, gallium scans and bone scans. A radionuclide scan is painless, except for a mild skin prick if the tracer is injected. Once the tracer is given, it takes several hours for the isotope to travel to the target organ. During this time, the patient usually can leave the test facility and return for the scan itself, which can last one to five hours. Radionuclide scans are done most commonly to detect cancerous tumors, to judge the effectiveness of cancer treatment and to look for signs that cancer has spread (metastasized) to organs such as the brain, liver or bones. Another common reason these scans are done is to assess the function of a gland, such as the heart or thyroid. (Locked) More »

Rapid Strep Test

A throat infection with streptococcus bacteria (called strep throat) needs to be treated with an antibiotic. A test is commonly used to find out whether streptococcus bacteria are present on your throat surface. The traditional test for a strep throat has been a throat culture, which takes two to three days to produce results. Several different types of rapid strep tests, however, can produce results within minutes to hours. A rapid strep test can only detect the presence of Group A strep, the one most likely to cause serious throat infections; it does not detect other kinds of strep or other bacteria. No preparation is necessary. A cotton swab is rubbed against the back of your throat to gather a sample of mucus. This takes only a second or two and makes some people feel a brief gagging or choking sensation. The mucus sample is then tested for a protein that comes from the strep bacteria. (Locked) More »

Skin Biopsy

Doctors take biopsies of areas that look abnormal and use them to detect cancer, precancerous cells, infections, and other conditions. For some biopsies, the doctor inserts a needle into the skin and draws out a sample; in other cases, tissue is removed during a surgical procedure. For this test, abnormal areas of skin are removed to test for cancer or other skin diseases. Tell your doctor if you have ever had an allergic reaction to the medicine lidocaine or similar types of local anesthesia. (Locked) More »

Snellen Test for Visual Acuity

A Snellen test uses a chart with different sizes of letters or forms to evaluate your visual acuity-that is, the sharpness of your vision. The test shows how accurately you can see from a distance. No preparation is necessary. You stand or sit at a specific distance from the eye chart. Usually you are told to cover one eye with a cardboard piece or with your hand while you read letters with the other eye and say them out loud for the doctor. (Locked) More »

Sputum Evaluation (and Sputum Induction)

If your doctor thinks you have pneumonia, he or she might examine a sample of your sputum, the phlegm that you cough out of your lungs, to try to determine what type of bacteria or other infectious agent might be the cause. Drink plenty of fluids the night before the test; this may help to produce a sample. You need to cough up a sample of sputum. To be useful for testing, the stuff you cough up has to be from deep within the lungs. If your cough is too shallow or dry, the doctor might ask you to breathe in a saltwater mist through a tube or mask. This mist makes you cough deeply that helps produce an excellent phlegm sample. (Locked) More »

Stereotactic Biopsy of the Breast

Stereotactic biopsy of the breast is a special type of large core needle biopsy. It is one method of guiding the biopsy needle to the desired location in the breast. Core needle biopsy can also be guided by ultrasound or by the standard x-ray techniques used in mammography. Large core needle biopsy is often the diagnostic method of choice to evaluate abnormalities that are visible on a mammogram but cannot easily be felt by hand. Core needle biopsy may not be suitable for women who have: In these situations, accurate results from a core needle biopsy may not be possible. Instead, your doctor may recommend a surgical biopsy. (Locked) More »