Step 3 -- Understanding Lab tests
Laboratory test samples are analyzed to determine whether the results fall within normal ranges. They also may be checked for changes from previous tests. Normal test values are usually given as a range, rather than as a specific number, because normal values vary from person to person. What is normal for one person may not be normal for another person. Many factors (including the patient’s sex, age, race, medical history, and general health) can affect test results. Sometimes, test results are affected by specific foods, drugs the patient is taking, and how closely the patient follows pre-test instructions. That is why a patient may be asked not to eat or drink for several hours before a test. It is also common for normal ranges to vary somewhat from laboratory to laboratory.

Some laboratory tests are precise, reliable indicators of specific health problems. Others provide more general information that simply gives doctors clues to possible health problems. Information obtained from laboratory tests may help doctors decide whether other tests or procedures are needed to make a diagnosis. The information may also help the doctor develop or revise a patient’s treatment plan. All laboratory test results must be interpreted in the context of the overall health of the patient and are generally used along with other exams or tests. The doctor who is familiar with the patient’s medical history and current condition is in the best position to explain test results and their implications. Patients are encouraged to discuss questions or concerns about laboratory test results with the doctor.

As you may know, lab tests are often known by many names. For example, a Complete Blood Count is also referred to as CBC or hemogram, among other names. The index below includes the formal test name and many of the alternate test names used to refer to the tests. As a result, it is a considerably longer list than the one included in the pop-down test menu at the top of the page. If you still do not find the test you are looking for in the list, enter the name into the Search box above, using quotation marks if the test name is more than one word, and click SEARCH.

Start Here for Further Information:

--Interpreting Lab test results (NIH--Cancer)

--Laboratory Tests (FDA)---

--Understanding Your Tests---(AACC)


Understanding Your Tests
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Like many areas in medicine, clinical lab testing often provides few simple answers to commonly asked questions. The issues - on topics like insurance reimbursement and reference ranges - can be very complex. While we can't offer the kinds of short, easy answers that we seem to be accustomed to in this information age, we have attempted in the following articles to break down the issues in a way that will help you to understand the issues a bit better and perhaps to ask the appropriate questions of your doctor.

Deciphering Your Lab Report
If you've had laboratory tests performed, you may have been given a copy of the report by the lab or your health care provider. Once you get your report, however, it may not be easy for you to read or understand, leaving you with more questions than answers. This article points out some of the different sections that may be found on a typical lab report, explains some of the information that may be found in those sections, and shows you an example of what a lab report may look like.

Reference Ranges and What They Mean
Test results are usually interpreted based on their relation to a reference range. This article will help to explain what a reference range is and why test results and references ranges should not be interpreted in a vacuum.

Evidence-Based Approach to Medicine Improves Patient Care
Medical knowledge is accumulating—and changing—with such dizzying speed that the medical community has found it needs new methods to cope with it all. Evidence-based medicine (EBM) is a formalized system for helping health professionals cope with this information explosion. This article explains what EBM is and the role of laboratory testing in its application.

How Reliable is Laboratory Testing?
Laboratory tests drive a large part of the clinical decisions our doctors make about our health, from diagnosis through therapy and prognosis. Given the crucial role that test data play in medical decision-making, we prepared this article to help you understand the key concepts and practices that are involved in making laboratory tests reliable.

The Universe of Genetic Testing
An increasing number of genetic tests are becoming available as a result of recent and rapid advances in biomedical research. It has been said that genetic testing may revolutionize the way many diseases are diagnosed. But genetic testing does not just help a physician diagnose disease. This article discusses genetic testing and the different reasons genetic tests are performed.

The World of Forensic Laboratory Testing
Forensic testing isn't quite like what you may see on television. This article explains what forensic testing is, when it is necessary, and dispels some of the misconceptions you may have about this form of laboratory testing.

Pharmacogenomics
Pharmacogenomics is the study of how drugs are metabolized in the body and the variations in the genes that produce the metabolizing enzymes. It offers doctors the opportunity to individualize drug therapy for patients based on their genetic make-up. This article provides specific examples of currently available tests in this category and describes some of the benefits and concerns with this area of laboratory testing.

Home Testing
As health care consumers continue to seek more convenience, particularly among chronic sufferers and the elderly, the home testing market is growing rapidly. Here's a glimpse at the market and the opportunities as well as the trade offs.

Collecting Samples for Testing
Today, laboratory technologies allow testing on a wide variety of samples collected from the human body, beyond just blood and urine. This article provides examples of samples that can be obtained as the body naturally eliminates them, those that are quick and easy to acquire since they reside in the body's orifices, and some that require minor surgery and anesthesia to access.

Putting New Laboratory Tests into Practice
Did you ever wonder why and how new lab tests are developed? How do they go from development to being used in medical practice? This five-part series of articles will answer these questions and more as they describe how different types of laboratory tests are developed, validated, and made available for use by patients and their health care providers.

Commercial Laboratory Tests and FDA Approval
The second in the series of articles mentioned above, this discusses the types of tests that are manufactured and sold in bulk to hospital and reference laboratories, clinics, doctors' offices, and other health care facilities. In the US, the development and marketing of these commercial tests are regulated by the Food and Drug Administration (FDA), and this article describes how these types of tests are classified.

Coping with Test Pain, Discomfort, and Anxiety
Nobody particularly enjoys having their 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. This series of articles has some tips on how to approach the experience with less stress. Other titles in the series include Tips on Blood Testing, Tips for Children, and Tips for the Elderly.

Staying Healthy in an Era of Patient Responsibility
As health care consumers have been given more responsibility for their care, more attention has been given to the value of preventive medicine. This article discusses how you can take an active role in your health care before you get sick, offering general suggestions as well as more detail on the role of screening tests.

Test Preparation: Your Role
One of the most important factors in determining the accuracy and reliability of your laboratory test is you, the patient. This brief article explains your role in the process and ways in which you may need to prepare for your lab tests.

Laboratory Methods
Labs use a variety of methods to test the numerous analytes that are of interest to the medical community. Understanding the method used for a test provides a broader context for understanding your test results. This article provides brief explanations of several common laboratory methods mentioned on this site.