WHAT IS LABORATORY TESTING?
Laboratory testing provides information (lab results) about the state of your health by the use of tests on blood, tissue, or body fluid specimens.

WHY LABORATORY TESTS?
Doctors and health care practitioners use lab tests along with your medical history, a physical exam, and other tests to make health care decisions that are vital to promoting better health and longer life for you.

WHO ORDERS AND INTERPRETS LAB TEST RESULTS?
In the state of Pennsylvania only certain licensed health care professionals, such as your physician, can order laboratory tests. Lab test results are used along with a physical exam and other diagnostic tests to make judgments about your health. For that reason, the doctor(s) or other medical professionals that provide your health care are in the best position to interpret your test results.

HOW ARE LAB TESTS USED?
Lab tests are useful in three ways:

• Screening -- identifies the risk of disease or medical condition in patients who present no symptoms. This allows for early diagnosis to better treat or to prevent disease from occurring. Good examples are the Pap test and cholesterol levels.

• Diagnosis -- to help to identify or exclude the presence of a condition or an illness in patients who have symptoms, such as a pregnancy test or a blood count for anemia. Sometimes the test tells the practitioner what stage a disease is in.

• Management -- to determine the prognosis or course the disease is likely to take, monitor how the disease progresses, determine if a disease is recurring, or to help select drugs or other treatment likely to help the patient. Antibiotic susceptibilities that predict how an infection will respond to specific drugs are an example of this type of test.

WHERE ARE LAB TESTS DONE?
Laboratory tests are performed in a clinical laboratory that is licensed by the Pennsylvania State Department of Health. The lab may also be certified by the Health Care Financing Administration (HCFA), and accredited by the College of American Pathologists (CAP).

Main Line Health Laboratories performs most testing at its core laboratory at Lankenau Hospital in Wynnewood, PA. Specimens may also be tested in the rapid response labs in Bryn Mawr Hospital in Bryn Mawr, and Paoli Memorial Hospital in Paoli, PA.

WHEN ARE LAB TESTS DONE?
Lab results need to be timely. Most tests are performed and the results are delivered to the doctor who ordered the test within 24 hours. Some tests take longer to complete, which is acceptable if your condition allows. Nearly all test results are reported to the physician within a week.

Sometimes, your state of health may require urgent care and lab results are needed rapidly. These tests are ordered “STAT”, a word that comes from the Latin statim, meaning “immediately.” Tests ordered STAT are reported to the doctor within minutes or hours if possible. These tests are performed in each Main Line Hospital in special “Rapid Response Labs.” Rapid response labs play a critical role for emergency departments and intensive care units.

HOW ACCURATE ARE LAB TESTS?
Lab test results are useful to the health care practitioner only if the results are accurate, precise, and timely. An accurate test result is one that closely corresponds to its true value. Testing should also be precise. In other words, the results of a particular test should be consistently reliable from patient to patient and from one time to the next.

The accuracy and precision of a particular test depend on many factors. Some tests are inherently more accurate than others. The laboratory takes specific measures to make sure that test results reported to your doctor are as accurate and precise as possible.

Blood test accuracy and precision are constantly monitored by the use of quality controls—specimens that have previously determined results. Controls are specimens that are tested with every “batch” or group of specimens. Their results are known by lab personnel and must closely correspond to their predetermined value. If not, the batch must be repeated. Proficiency testing specimens are controls sent to the laboratory from an outside source—either from a governmental or private organization. The results are unknown to the lab personnel and must be accurately reported for the laboratory to maintain its license or certification.

There are several government and independent organizations which monitor lab testing quality. Among them are HCFA, the Pennsylvania State Department of Health, and the CAP. These organizations also periodically inspect the laboratory and laboratory records from time to time.

Laboratories also maintain their own quality assurance standards. The Quality Assurance Committee of Main Line Health Laboratories, under the leadership of the Medical Director, Dr. Albert Keshgegian, constantly monitors lab test accuracy and precision as well as other aspects of the lab process from the drawing of the specimen to the reporting of results.