Laboratory testing provides information (lab results) about the state of
your health by the use of tests on blood, tissue or body fluid
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
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: Lab tests identify the risk of
disease or a medical condition in patients who present no
symptoms. This allows for early diagnosis, which enables doctors
to better treat or to prevent disease from occurring. Good
examples are the Pap test and cholesterol levels.
Diagnosis: Lab tests help identify or exclude
the presence of a condition or an illness in patients who have
symptoms. Examples include a pregnancy test or a blood count for
anemia. Sometimes lab tests tell the practitioner what stage a
disease is in.
Management: Lab tests help doctors determine
the prognosis or course a disease is likely to take, monitor how
the disease progresses, determine if a disease is recurring and
decide on what drugs or other treatments will be likely to help
a 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 clinical laboratories that are
licensed by the Pennsylvania State Department of Health. A lab may also
be certified by the Health Care Financing Administration (HCFA) and
accredited by the College of American Pathologists (CAP).
Main Line Hospitals Laboratory Services performs most testing at its
core laboratory at Lankenau Medical Center in Wynnewood, Pa. Specimens
may also be tested in the rapid response labs in Bryn Mawr Hospital and
How long does it take to get lab test results?
Lab results need to be timely. Most test results are delivered to the
doctor who ordered the test within 24 hours of when the test is
performed. 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, an
abbreviation for the Latin word 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
The accuracy and precision of a particular test depend on many factors.
Some tests are inherently more accurate than others. The lab 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 lab to maintain its license or
There are several government and independent organizations that monitor
lab testing quality. Among them are HCFA, the Pennsylvania State
Department of Health and the CAP. These organizations also periodically
inspect laboratories and their records from time to time.
Laboratories also maintain their own quality assurance standards. The
Quality Assurance Committee of Main Line Hospitals Laboratory Services,
under the leadership of the medical director, Dr. Pradeep Bhagat,
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.
For more information, call 1.866.CALL.MLH.