CLINICAL LAB SCIENEC

CHAPTER 4: HOSPITAL AND LABORATORY ORGANIZATION 83
Serology (Immunology)
Serological tests to determine the immune response to an organism are performed
in several sections of the laboratory and not in a single department. However,
the importance of this variety of procedures requires that they be performed in
a unique department. The immune system is the basis of protecting the body
from invasions by microorganisms such as bacteria, viruses, rickettsiae (bacterial
form of an intracellular parasite, a term that is not often used today), fungi, and
parasites such as protozoa. When the body is attacked, the immune system leaps
to the body’s defense, and its activity in protecting itself gives information that
can be used to diagnose the illness.
White cells attack organisms directly, but the liquid portion of the blood
will contain proteins called antibodies when an organism is introduced into the
body. These antibodies are almost completely specific to a particular organism,
with some exceptions, and if the laboratory worker tests for these antibodies, it
is an indirect test for infection by specific antigens (the organism is the antigen in
infections). Allergy tests utilize several mechanisms to determine the products to
which a patient may suffer an allergic reaction when coming in contact with the
body. This is also a serological test. Other serological tests are available to test
for the toxins produced by certain organisms. In some cases, a direct test is done
by testing for the actual organism itself (bacterial, viral) rather than by testing
for antibodies produced against the organism or for the toxins it produces.
Serological tests are usually performed in batches as most of the work is
of a nonemergency nature. Some of these tests may be performed in chemistry
or microbiology departments and some automation is available, but there
remains a great deal of manual, hands-on work. The serology procedures
are evolving rapidly as new technology emerges, and immunologic hormones,
lymphokines, and monokines from certain lines of white cells have
been isolated and are used to treat diseases that were previously untreatable,
such as certain types of cancers. Sophisticated instrumentation is
being developed to utilize the increasingly larger numbers of antibodies in
increasingly smaller quantities that may be used to fight certain infections
and diseases. This department could grow exponentially in coming years
with new developments.
Microbiology
Detecting the presence of and identifying pathogenic (disease-causing)
microorganisms is the focus of the microbiology laboratory. Microbiological
studies represent one of the earliest efforts to detect and treat human
diseases in the laboratory. The early development of the microscope by
Antonie van Leeuwenhoek (Figure 4-1) in the late 1600s gave a boost to
correlating the presence of microorganisms and certain diseases, as the
device enabled a visual picture of causative germs.
Clinical microbiology includes the study of bacteria, viruses, fungi,
and parasites. In the case of parasitology, protozoa may be visualized and
the eggs of many intestinal parasites found in the stool; this facilitates the
diagnosis of a parasitic infection. Bacteriology is a major area of most
FIGURE 4-1 Drawing of an old
microscope.
Source: Delmar/Cengage Learning.
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