Physicians and Diagnostic Procedures - Common screening tests



A variety of tests may be given in a routine physical exam, depending on the patient's age, family history, and current state of health. Some of the following tests will be done each time the patient visits the doctor and some are necessary only when specific complaints or concerns are raised or when an individual reaches a certain age or risk category. Your doctor should explain any new test to you.

Blood Pressure and Pulse Rate

The patient's blood pressure and pulse rate are checked on every office visit. Blood pressure is measured with a sphygmomanometer and a stethoscope. The sphygmomanometer is attached to an inflatable cuff, which is wrapped around the upper arm; a rubber bulb is used to inflate the cuff and increase pressure in it so that it can control the blood flow in the arm. The physician locates the pulse with the stethoscope and increases the cuff pressure until the pulse (heartbeat) can no longer be heard. Then the physician slowly deflates the cuff and lets the reading on the gauge fall gradually until he hears the first beat of the heart. The reading on the gauge at that point is recorded as the systolic pressure . The physician continues to relax the pressure in the cuff and watches for the reading at the point where the thumping of the heart disappears again. That number is recorded as the diastolic pressure .

The doctor checks a patient's pulse rate to find out if the heart is beating normally. The pulse is the rhythmic expansion of the arteries that takes place after each heart beat. The pulse rate is the number of pulsations of an artery per minute. The normal pulse rate for a person at rest varies from as little as 50 for elderly people to as much as 100 for children.

Eyes, Mouth, and Ears

Inspection of the eyes is usually done with the aid of an ophthalmoscope , with which the physician can see the retina at the back of the eye. Distended retinal veins may be a sign of a variety of disorders, including diabetes or heart disease; signs of hardening of the arteries also may be observed in the eyes before other indications are found elsewhere. The condition of retinal blood vessels may also signal the development of hypertension.

A device called an otoscope is inserted in the outer ear to examine the external auditory canal and eardrum. The condition of the tongue, teeth, and gums can reveal much about the health of the individual.

Cholesterol Measurement

An elevated blood cholesterol level is an important risk factor for coronary artery disease. For most people a blood cholesterol level above 200 mg/dl should be cause for concern, indicating a need for further tests and perhaps a change in life-style.

Blood cholesterol levels are measured by withdrawing a small amount of blood—usually from the arm—to be analyzed in a lab. The result is given in terms of milligrams of cholesterol per deciliter of blood. It's a good idea to have your blood cholesterol checked at age 25 and then once every 3 to 5 years thereafter.

Blood Tests

Complete Blood Count

A Complete Blood Count ( CBC ) provides the physician with more information than any other single laboratory screening procedure. Four common measurements are taken from it:

Hemoglobin concentration . Hemoglobin is the chemical substance that transports oxygen through the bloodstream to all the cells of the body. This measurement determines the amount of hemoglobin per unit volume of blood.

Red blood cell count . This test measures the number of red cells per cubic millimeter of blood. A low red blood cell count may indicate anemia, as well as be a potential early warning sign for leukemia, kidney malfunction, internal bleeding, or sickle cell anemia.

Hematocrit . The hematocrit measures the ratio of red blood cells to the plasma in the blood. like the hemoglobin concentration and the red blood cell count, the hematocrit can indicate anemia, and all three tests are generally given in order to help diagnose the specific type and cause of anemia.

White blood cell count . This test measures the number of white cells per cubic millimeter of blood. A high white blood cell count can indicate an infection, a major injury, or even leukemia. A low count can be a sign of poor diet, certain infections, or another type of leukemia. If taken in the presence of a fever, the white blood cell count can help distinguish between a bacterial and a viral infection.

Blood Glucose

The glucose test determines the amount of sugar in the blood. Individuals who experience symptoms of diabetes mellitus (such as excessive thirst or urination), hypoglycemia (lightheadedness or fainting), or who are pregnant will most likely be given a blood glucose test. A very high level of blood sugar can indicate diabetes, while a very low level can indicate hypoglycemia. In either case or in border-line cases an oral glucose tolerance test is given. This test requires that the individual fast for 12 to 14 hours before the test. The patient is then given a concentrated sugar solution to drink, and blood is drawn at regular intervals over the next several hours. This test has replaced the urine test for sugar.

Blood Urea Nitrogen (BUN) and Blood Creatinine

Blood urea and creatinine are products of protein metabolism. A high level of either in the blood means that the kidneys are not filtering them properly from the blood, possibly because of kidney damage.

Blood Electrolytes

The four blood electrolytes are sodium, potassium, chloride, and bicarbonate, and they play important roles in the blood pH, the cells’ water balance, and kidney function. Most often this test is given to patients who are taking diuretics, those with liver, kidney, or heart disease, or those who may be experiencing dehydration or excessive vomiting or diarrhea.

Urinalysis

The urinalysis is a simple and important test that can indicate much about a person's overall health and identify potential problems, such as kidney disease, diabetes, and urinary tract infections. For a routine urinalysis a sample can be taken at any time of day, although the physician may specify the first morning's urine, or may give special instructions about food and water intake before taking the urine sample.

Urinalysis includes a specific gravity test (a test to measure the extent to which solids are concentrated in the urine as an indication of how well the kidneys are conserving the body's fluids) and a pH test (a test to measure the acidity of the urine as an indication of how well the kidneys are able to remove acid wastes).

There are also tests for the presence of glucose (sugar), protein, blood, and bilirubin (a substance produced in the liver from the breakdown of old blood cells); none of these substances is normally found in the urine. The presence of glucose is an indication of diabetes; protein in the urine is associated with diabetes, hypertension, and other diseases; blood in the urine can indicate many problems including kidney stones, cysts, infection, and cancer; the presence of bilirubin suggests a problem in the liver or bile ducts. The presence of bacteria or of a large number of white blood cells is typically an indication of a urinary tract infection.

Routine blood work and a urinalysis are simple, common tests that can catch many potential problems early. When abnormalities exist, other, more specific—and often more expensive—tests are required for confirmation before treatment can begin. Given the fact that any test can give a false result, whether through human error or through individual variations, the question of whether or not individuals should have these tests is a much-debated point in the medical community and one best discussed with one's primary care physician.

Electrocardiogram

The electrocardiogram (ECG or EKG) measures heart activity by detecting the electrical activity in the heart. Electrodes attached to the chest, neck, arms, and legs record the pathway of electrical impulses through the heart muscle and record these impulses as tracings on special graph paper. The test is simple and safe, and takes five to ten minutes to perform.

The purpose of the EKG is to detect heart disorders or blockages in the coronary arteries. A normally beating heart produces basically the same pattern of waves in all people.

Variations in this pattern can indicate a number of potential problems: irregular heart rhythms, damage to the heart muscle, enlargement of the heart's chambers, mineral imbalances in the blood. The EKG can also reveal whether the patient has had, or is having, a heart attack.

This test is not foolproof, however, and can produce false results. Some people with normal EKGs have heart trouble, and the graph may show abnormalities where none exists.

EKGs are usually a routine part of a physical checkup after age 40; before that age, patients are recommended to have at least one EKG to use for comparison later.

Cancer Screening Test

Carcinoembryonic antigen (CEA), a substance normally found only in fetuses, may indicate the presence of certain cancers when found at elevated levels in adults. This test is typically used in patients who have been treated for such cancers as colon/rectal, breast, lung, ovarian, pancreatic, and stomach to check for possible recurrence of the disease.

Mammogram

A mammogram is an X ray of the breast done to locate breast tumors and cysts. To date, it is the only screening exam that can find small tumors before they can be felt and when they have the greatest chance of being cured. It is estimated that yearly mammograms for women over 40 could lead to a one-third reduction in the number of deaths from breast cancer.

The patient must remove all clothing from the waist up and stand with the breast placed on a small shelf that extends out from the machine.

The patient is then guided forward so that the edge of the shelf presses into the chest just below the breast. A compression device is brought down onto the breast, and pressure is applied for less than 30 seconds. This is the most uncomfortable part of the test, as much pressure is necessary in order to get the most detailed picture possible and use the least amount of radiation. Eliminating caffeine and foods that tend to cause water retention two weeks prior to the exam makes the breasts less sensitive.

The American Cancer Society recommends that women aged 40 and older have a mammagram every year.

For more information and a comparison of diagnostic and screening mammograms, see , Ch. 25, “Cancer of the Breast.”

Pap Smear

The pap smear tests for cervical cancer by the microscopic examination of cells from the vaginal walls and cervix. Although it is not infallible, this test detects 95 percent of cervical cancers; it is an important aid in the detection of this disease at a stage when it is often without symptoms and it is still curable.

The procedure can be done any time except during the menstrual period. The patient undresses from the waist down and lies down on her back with her legs spread apart and her feet in special stirrups. The physician inserts a lubricated speculum into the vagina and opens it to expose the cervix and its os (mouth). The doctor then inserts a small applicator through the speculum and rubs it gently against the cervix and sometimes the os. The applicator is removed and rubbed onto a glass slide (the smear). The speculum is then removed.

The first pap smear should be done when a woman turns 18 or becomes sexually active (whichever occurs first), and should be followed by pap smears for 2 consecutive years. Providing these tests are negative and there are no risk factors present, tests can be done less frequently at the discretion of one's doctor, although an annual pap smear for women between 25 and 60 is common.

Prostate Tests

Cancer of the prostate is a leading cause of death in men over 50. If detected early, prostate cancer can usually be cured. It can often be detected by digital rectal examination (DRE), a routine procedure in which the doctor inserts a gloved finger into the rectum and feels the prostate gland. Another test measures blood levels of the prostate-specific antigen (PSA), a protein produced in the prostate that may be elevated when cancer is present.

Occult Blood Test

Colon cancer is the second most common form of cancer in the United States. An early warning sign of colon cancer is blood in the stool. It is called occult , or hidden, blood because it cannot be detected by sight. It is recommended that everyone over age 50 be tested for occult blood annually.

Usually, stools are tested for occult blood at home with the help of a self-test kit. The test calls for smearing cards with stool samples collected over several days. The samples are sent to a lab to be tested for hidden blood. If blood is detected, further diagnostic tests, including a colonoscopy (a visual examination of the entire colon), may be ordered.

Sigmoidoscopy

Another procedure for detecting colon cancer is sigmoidoscopy , the use of a tubular scope called a sigmoidoscope to examine the lower segment of the large intestine. The purpose of this test is to detect tumors in the rectum and colon. To ensure a clean lower bowel, the patient must follow a special diet—typically an all-liquid diet—for several days prior to the test, use laxatives the night before, and take an enema on the day of the test. The patient puts on a hospital gown and lies on the left side with the knees drawn up to the chest. A thin, lubricated tube is inserted into the rectum and slowly advanced along the large intestine. The tube contains optical filaments through which light can pass and transmit images to a microscope or monitor for the doctor to view. It may also contain small instruments that enable the doctor to take tissue samples. Air may be forced through the tube to expand the intestine, which can cause a feeling of discomfort. The procedure takes from 15 to 30 minutes. The American Cancer Society recommends a baseline sigmoidoscopy for everyone at age 50 (or 40 if there is a family history of colon cancer) and once every three years after that.

Sexually Transmitted Diseases

The prevalence of sexually transmitted diseases (STDs), such as syphilis, gonorrhea, chlamydia, genital herpes, and AIDS makes regular tests for these diseases in sexually active people who are not in monogamous relationships vitally important. Tests are typically blood tests or swab tests and should be done every year or two.

Tuberculosis

Tuberculosis is normally tested for with a simple skin test . The forearm is either pricked with a small device with four prongs or a subcutaneous injection is used. In either case, the patient is asked to check the area after 48 to 72 hours for signs of redness, raised bumps, or swelling.

Stress Test

Stress tests are often given to older people who are about to begin an exercise program. During this test, the heart's activity is monitored with an electrocardiogram (EKG) while the patient exercises on a treadmill or stationary bicycle. The procedure is usually done in a physician's office or a local hospital. It is a troubleshooting test designed to reveal problems that a resting EKG does not. At rest, an EKG may indicate that the heart is receiving sufficient oxygen; but with exertion, as the heart's workload increases, the exercise stress test may reveal signs of an inadequate oxygen supply to certain areas of the heart muscle. The most common cause of this condition is a narrowing of coronary arteries due to a buildup of plaque. Thus the stress test can help identify an abnormality that might otherwise go undetected until a person is exercising and unexpectedly experiences chest pain. A routine stress test is often recommended at age 45, and as early as 35 if the patient has at least one risk factor for coronary artery disease. Risk factors include smoking, obesity, hypertension, and elevated cholesterol levels.

Electrocardiogram

Chest X ray

The chest X ray was once a routine part of the physical exam. Its expense, potential danger, and limited results in the absence of symptoms has made it less popular. (An individual X ray in and of itself is not harmful, but because exposure to radiation is cumulative throughout your life, a series of X rays over a lifetime can result in increased risk of cancer.) A chest X ray produces a picture that includes the heart and lungs. It can be useful in identifying certain heart problems, and is also used to detect lung cancer.

If you are advised to have a chest X ray, you will be asked to remove all clothing from the waist up and to wear a gown. Depending on the particular area to be X rayed, you will either sit, stand, or lie down. Generally two or three exposures are taken for each area targeted.

Immunizations

Nearly everyone knows the importance of having their children immunized, but many people may not realize that it is important for adults to have regular immunizations as well. When a patient is immunized, he or she receives a shot of modified microbes (bacteria or viruses) or toxins. Although not strong enough to actually give the patient the disease, the dose of microbes does stimulate the patient's own immune system to build up antibodies against the disease, thus making him or her immune to future exposures. Vaccines do wear off, however, and it is best to keep a record of all immunizations and receive scheduled booster shots.

Diphtheria

Diphtheria is spread by airborne bacteria that release toxins that can attack the heart and other internal organs. Adults should receive a booster shot every ten years.

Tetanus

Tetanus is spread by bacteria that enter the body through a contaminated wound. Adults should receive a booster shot (often combined with the diphtheria shot) every ten years. If you sustain a contaminated wound, your doctor may recommend a tetanus booster is you have not had one in 5 years.

Influenza

The risk of death from the flu increases with age, and people over 65 are strongly advised to receive annual flu shots in the fall. In 1976 about 500 cases of a rare paralytic condition called Guillain-Barre syndrome were associated with a swine flu vaccine. No influenza vaccines since have been associated with the development of Guillain-Barre.

Pneumococcal Pneumonia

A vaccine is available that offers protection against the 23 strains of bacteria that cause about 80 percent of pneumococcal diseases in the United States. All adults age 65 and older should receive the pneumonia vaccine on an annual basis, as should younger adults with chronic cardiopulmonary disorders, diabetes, renal disease, liver disease, blood diseases, cancers, and diseases that suppress immunity such as HIV infection.

Those at risk of death from influenza should also be immunized with the pneumonia vaccine, but only once. Because it may increase adverse side effects, repeat or booster shots of the vaccine are not recommended.

Measles and Mumps

Many people born after 1957 have not had and have not been immunized against measles and mumps and thus are particularly susceptible to these diseases. In addition, those vaccinated between 1963 and 1967 may have gotten a short-lasting killed-virus vaccine and should be revaccinated. Anyone born between 1957 and 1967 should be revaccinated unless 1) they had a case of measles confirmed by a physician's diagnosis, 2) they are immune, as demonstrated by a blood test, 3) they have a record of receiving live vaccine no earlier than their first birthday.

Hepatitis A

Hepatitis is an inflammation of the liver, usually caused by a virus infection. Hepatitis A is the most common form of the disease. It is transmitted mainly by contaminated food or water. Symptoms include fever, nausea, vomiting, and jaundice.

There is a safe and effective vaccine available to people at high risk for the disease and to travelers to countries where hepatitis A is endemic.

Hepatitis B

Like the HIV virus that causes AIDS, hepatitis B is spread through blood contact with virus-infected body fluids; the most common form of transmission is sexual contact. However, hepatitis B is much more contagious than the HIV virus and is the leading cause of cirrhosis and cancer of the liver. Half of those infected with hepatitis B never develop symptoms, and thus become unwitting chronic carriers of it. Vaccination is strongly recommended, especially for those with a high risk of infection, such as health care workers, sexually active persons with multiple partners, intravenous drug users, hemodialysis patients, newborns with infected mothers, and residents and staff of institutions for the mentally retarded.

Children

The standard immunizations for children are 1) combined vaccines for diphtheria, pertussis, and tetanus (DPT); 2) a triple oral polio virus vaccine or TOPV; 3) vaccines for measles, mumps, and rubella (MMR); 4) hemophilus influenza type B conjugate vaccine (HIB). The Centers for Disease Control recommends the following schedule:

  1. • 2 months: DPT, TOPV, HIB
  2. • 4 months: DPT, TOPV, HIB
  3. • 6 months: DPT and HIB
  4. • 12 months: DPT, TOPV, HIB, TB test, MMR
  5. • 4 to 6 years: DPT, MMR, and TOPV

Hepatitis B and chicken pox vaccines are also available.



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