Nobody particularly enjoys having blood drawn or providing a urine or stool sample, but a medical test conducted on a small sample collected from your body can give your doctor information that can help save or improve the quality of your life. Most people get through their medical tests just fine even though they may feel some embarrassment, discomfort, or anxiety at the outset. If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, read this for some general tips on how to make the sample collection experience more positive and less stressful.

Your physician uses medical tests to help ensure accurate and timely diagnosis of conditions that could seriously affect your health. Tests also help your physician monitor your therapy. As bothersome as it may seem to undergo the testing, the good news is that the tests in use today are more accurate and useful than ever. They also tend to be significantly less intrusive.
Sometimes, undergoing an unfamiliar medical procedure can turn out to be a tense, upsetting, or even frightening experience. With a little preparation, however, you can help ensure that your lab test is as quick, painless, and accurate as possible. Emotional distress is more likely when your experience with a medical procedure does not match your expectations. Knowing what will happen is a good way to maintain composure.

Understanding why a medical test has been ordered can improve your attitude and preparation for the test. Being well prepared also helps you feel more relaxed and in control of the situation. Ask your physician to explain the reasons for your test and how the test will be conducted.

When a test is ordered for you, you should find out why the test needs to be done, how it will be done, and what the physician expects to learn from it. Here are some good questions to ask:

Many of the tests your doctor orders for you today are less intrusive and more comfortable than the older, less accurate tests they have replaced.
A variety of specimen collection equipment has also been designed with patient comfort in mind.
Don't hesitate to request a modification or a different approach that better suits your needs. You can expect that the health professionals responsible for collecting the sample have been trained to be sensitive to the needs of apprehensive patients and people with special needs. They have some proven strategies to help you and are usually willing to listen to you to determine what will work best in a situation.

Test results are usually interpreted based on their relation to a reference range.

The "Normal" or Reference Range
"Your test was out of the normal range," your doctor says to you, handing you a sheet of paper with a set of test results, numbers on a page. Your heart starts to race in fear that you are really sick. But what does this statement mean, "Out of the normal range"? Is it cause for concern? The brief answer is that a result out of the normal range is a signal that further investigation is needed.
The interpretation of any clinical laboratory test involves an important concept in comparing the patient's results to the test's "reference range." (It's also commonly called the "normal range" but today reference range is considered a more descriptive term.

Some tests provide a simple yes or no answer.
A typical lab report will have your results followed by a normal or reference range. For example, your results for a thyroid-stimulating hormone (TSH) test might look something like: 2.0 m-IU/L, ref range 0.5 - 5.0 m-IU/L. The test results indicate that it falls within the "normal" range.

How was that reference range established? The short answer is: by testing a large number of healthy people and observing what appears to be "normal" for them.

For many tests, there is no single reference range that applies to everyone because the tests performed may be affected by the age and sex of the patient, as well as many other considerations.
Alkaline phosphatase is an enzyme found in the cells that make bone, so its concentration in the body rises in proportion to new bone cell production. In a child or adolescent, a high alkaline phosphatase level is not only normal but also desirable-the child should be growing healthy bones. But these same levels found in an adult are a sign of trouble-osteoporosis, metastatic bone disease (extra bone growth associated with tumors), or other conditions. So experience from testing large numbers of people has led to different reference ranges by age group.

Hemoglobin and hematocrit (a red blood cell measure) both decline as a natural part of the aging process.
The patient's sex is another important consideration for many tests.

Creatinine is produced as a natural by-product of muscle activity and then removed from your bloodstream by your kidneys. Because males have greater muscle mass than females, the reference range for males is higher than for females.
As another example, blood loss through menstruation may cause lower hemoglobin and hematocrit levels in pre-menopausal women.

Of course, the result may indicate a problem. The first thing your doctor is likely to do is to re-run the test. Perhaps the analyte being measured happened to be high that day due to one of the reasons stated above, or perhaps something went awry with the sample (the blood specimen was not refrigerated, or the serum was not separated from the red cells, or it was exposed to heat).
Laboratories will generally report the findings based on age and sex, and leave it to the physician to interpret the results based on factors such as diet, your level of activity, or medications you are taking.

If you know of any special circumstances that could affect a test, mention them to your doctor; don't assume your doctor has thought of every possible circumstance.

From the moment a test is ordered, attention to detail becomes an issue critical to the quality of your lab results.

To make it easier to see all the points where quality is monitored - and the areas where the quality of your input is important - we have divided the tasks into three main phases:

Pre-Analytical Activities: what happens when the test is ordered and the sample is collected

Analytical Activities: what happens in the lab where the test is conducted?

Post-Analytical Activities: what happens between the time the test is run and the results are reported

Reliability of test data is high because attention to quality is paid every step of the way:
Test is ordered --> Sample is collected --> Test is run --> Results are reported

In the lab where the specimen is analyzed, quality assurance procedures guide and monitor all related activities, including the following:

As test results are made available, work quality continues to be monitored in areas such as the following:

The Careful Clinician
Laboratory testing is a science professionally conducted with rigorous statistical analysis and quality controls. But medical diagnosis has been called an art, a clinical reasoning process, not always clear cut, which relies on information from multiple sources. Medical testing is an important component in the diagnostic tool kit, and very often an invaluable tool, but it is most reliable when used in conjunction with other meaningful data collected in the diagnostic process.

...and The Careful Patient
You can put great trust in the data generated by today's exacting medical tests. A caveat to remember is that a diagnosis and treatment plan for a serious disease should never be based on a single medical test. Test findings are just one of the pieces of the diagnostic puzzle. Please follow test preparation instructions carefully and tell the person collecting your sample about any exceptions you made.