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Have There Been Any
Scientific Advances In Pap Tests?
Liquid-based Pap tests have been designed to address and improve the
acknowledged limitations associated with the conventional Pap smear.
The liquid-based Pap test is a revolutionary improvement in this
screening test. The main difference between the liquid-based Pap test
and the conventional Pap smear is in the preparation of the cellular
specimen. The health care practitioner takes the cellular sample in the
same manner as the Pap smear, utilizing a plastic spatula/endocervical
brush combination or cervix broom, but rather than smear the cells on a
slide, the implements are immediately rinsed in an alcohol based
solution that immediately preserves the cells and clears some of the
elements which would obscure the cells in questions, such as blood and
mucus. All of the cells sampled are in the vial of alcohol preservative
fluid. This vial is then sent to the laboratory for special processing.
The laboratory uses a special filtering technique (Cytyc ThinPrep) to
apply a random distribution of the cellular sample onto a slide
resulting in a clean, even layer of cells for microscopic examination.
A cervical specimen prepared by the liquid-based method usually results
in a more accurate review and interpretation of the Pap test. Centrex
Clinical Laboratories, Inc., was the first laboratory in Upstate New
York to implement this test.
Can The Laboratory Test For Anything Else With The
Pap Specimen?
New tests have been developed to detect the causative agent of cervical
cancer, human papillomavirus (HPV), which can also be performed on the
same vial that the liquid-based Pap test used. Centrex has also
implemented a reflex testing protocol for clinicians to test for the
presence of HPV on the same vial that has an atypical Pap result. This
can potentially save the patient a return trip to the doctor as well as
prevent unnecessary biopsies if the results are negative. However, if
HPV is detected, the doctor can perform colposcopy (look at the cervix
and vagina with a microscope for lesions) and take appropriate
biopsies. This is a more effective way to manage the patient, and more
importantly, a serious lesion can be detected earlier.
Why Should Pap Tests Be Performed Every Year If
Results Always Come Back Okay?
It is important to remember that the Pap test alone is only a screening
test. Although it has been quite effective in reducing the incidents of
invasive cervical cancer, this test alone is not a diagnostic test. It
often does not reliably predict the presence of high-grade lesions and
cervical cancer, consequently, it is necessary to be screened on a
regular basis, particularly if the patient has any of the risk factors
for cervical cancer. HPV infection is the most significant risk factor
in the development of cervical cancer. It is one of the most common
sexually transmitted infections in both men and women and very
contagious. It can remain dormant for years without showing physical
signs and symptoms of disease. Even when a pap test comes back
“within normal limits” and the woman has no risk
factors, it is extremely important to visit the doctor on a regular
basis, preferably annually, to have a complete physical, including a
pelvic exam with a liquid-based Pap test with reflexive HPV testing and
a breast exam. Routine doctor visits and annual Pap tests are the best
practices in early detection of diseases.
What Is HPV?
HPV is actually a family of viruses of more than 70 types, most of
which have been grouped into two classifications, high and low risk.
More than 99% of cervical cancers have detectable high risk HPV, and
thus, an infection with high risk HPV has a greater chance of
progression to cervical cancer. These high risk HPV types are more
virulent because of their ability to integrate their DNA into the
infected cell’s DNA and turn the cell into an
“immortal”, abnormal cell. The low risk HPV types
are those usually seen in warts. In healthy women, the majority of the
low risk infections are cleared by the immune system; however, it is
more difficult for the body to fight the high-risk HPV types. Centrex
has a test, the HPV Hybrid Capture II, to detect both low and high risk
HPV types and is at the cutting-edge of implementation of an even more
specific HPV test, the HPV DNA in-situ hybridization test. Both of
these tests can be performed on the same liquid-based sample submitted
for the ThinPrep Pap test.
What Are The Risk
Factors For HPV & Cervical Cancer?
Risk factors in women include the
following:
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Women who became sexually active
at a young age (before 17 years old)
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Women with a history of multiple
sexual partners
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Women whose partner has had
other sexual partners
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Women with a history of other
sexually transmitted diseases & external genital warts
(condyloma)
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Women who gave birth to her
first child prior to age 20, or who has had numerous pregnancies
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Women whose mothers took DES
while they were pregnant
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Women who smoke and/or are
immunocompromised, for example, are infected with HIV,
are also at more risk to develop cervical cancer after infection with
HPV
For more detailed information on
pap smears and ThinPrep technology check out ThinPrep.com
At your next annual physical, ask your physician to perform the
ThinPrep Pap test and recommend it be sent to Centrex
Clinical Laboratories, Inc., where you can count on the
accuracy of the results.
Centrex is now reporting pap smear results in the Bethesda
System 2001. Physicians interested in the new reporting
terminology are encouraged to contact our Technical Support or Cytology
Department at 1.800.562.1550.
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