Screening Versus STD Testing and the Practical Implications
The difference between sexually transmitted disease (STD) and sexually transmitted
infection (STI) is more than a semantic one and has implications with respect to the setting in which screening
tests are ordered and the cost of tests.
Infectious disease of any type differs from infection alone in that disease connotes signs and/or symptoms of
illness. Likewise STD differs from STI in that STD is associated with signs and/or symptoms of the infection
causing the STD, whereas as STI is oftentimes silent and hidden. Although the latter is sometimes referred to as
asymptomatic STD the more appropriate or accurate term is STI because it is a state of being infected with or
without signs or STD symptoms. In essence, STI, which came into vogue in recent years, is an all-inclusive term,
which refers to both STD and sexually transmitted infection. It also represents what used to be commonly called
venereal disease or VD.
A glaring example of the distinction between STD and STI is acquired immune deficiency syndrome (AIDS) and HIV
infection. AIDS is the result of infection with the HIV virus, but not everyone with HIV infection has AIDS.
Individuals with AIDS have significant signs and STD symptoms associated with the infection including evidence of
weakening of the immune system resulting in the predisposition for becoming secondarily infected with other germs
that don't normally infect people with intact immune systems. Individuals infected with the HIV virus but without
AIDS symptoms or signs of a compromised immune system are at risk of developing AIDS but until evidence of disease
is manifested are considered to have just HIV infection.
The semantic difference between STD and STI has implications with respect to test proceedings. Since disease is
associated with signs and/ or symptoms of illness, disease testing is performed when disease is suspected based on
the presence of either or both of these indicators of illness. Disease screening on the other hand, is the testing
performed when one has an increased likelihood of illness even though signs and/or symptoms of the particular
illness are not present at the time of testing. Screening tests for heart disease, for example, might be based on a
positive family history of heart disease, obesity, or other risk factors such as high blood pressure. Similarly,
STI screening is performed based on the likelihood of STI because of an increased risk based on one's sexual
activity. Conversely, STD testing is performed to confirm or exclude suspected disease based on the presence of
symptoms or signs of STD.
The semantic distinction between STI screening and STD testing influences the setting in which tests are ordered
and the cost of testing. If one has health insurance and undergoes testing according to a doctor’s order because of
STD symptoms or signs the test(s) are generally billed to the insurance company and paid for by the insurance
carrier. On the other hand, if one undergoes STI screening as ordered by a physician the cost of the test(s) in
most instances will not be covered by the health insurance carrier, in which case the individual tested would be
responsible for the cost of the tests.
Before paying claims health insurance companies determine if services were appropriate based on the reason(s)
they were provided. Every service including laboratory tests has a unique service code called a CPT code, and
every diagnosis, whether it is a specific disease or a matching sign or symptom of a particular disease, has a
unique diagnosis code called an ICD-9 (soon to be changed to ICD-10) code. Since the diagnosis code conveys the
reason a particular service was provided insurance companies compare the two codes during the claim review process.
If the diagnosis code supports the service code the claim is paid as long the service provided is a benefit of the
particular health insurance plan. Therefore, if appropriate STD/STI testing is done to establish a diagnosis, a
supporting diagnosis code will exist to justify payment of the insurance claim. In contrast however, a valid
diagnosis code will not exist to justify STI screening because of the absence of symptoms or signs of STD, in which
case the health insurance carrier generally would not cover the cost of the test(s) unless limited STI screening is
a special benefit of the particular insurance plan.
Because the cost of STI screening ordered through a doctor’s office or clinic can be quite expensive and is not
covered by insurance, comprehensive screening is usually not ordered in that setting, and is not included with
a wellness health exam because of the absence of symptoms or signs of STD. An online STD/STI testing service,
however, is a viable option inasmuch as it offers comprehensive screening test panels at a considerably lower
price and provides private online test ordering as well as confidential online test results. Some services provide
testing for trichomonas, Chlamydia, gonorrhea and HIV on specimens privately collected and mailed in.
An increased understanding of STI screening and its role in reducing the transmission
of sexually transmitted infections, hopefully will engender an enhanced rate of screening and thus be instrumental
in stemming the tide of the current STD/STI epidemic which currently plagues our
Victor E. Battles, M.D. is a board-certified internist with 30 + years of patient
contact. Dr. Battles has been a principal investigator in several clinical research trials and is the founder of
Proactive Health Outlet, a resource providing self-help for improving health. For more information about and herpes
testing options visit Proactive Health Outlet.
by Victor Battles - January 24, 2013
For sources of STD'STI testing and screening click here.