Cystic Fibrosis
New Alternatives for Prenatal Screening
Medco Forum, April 2003

AmeriPath Inc. now offers cystic fibrosis (CF) testing from the liquid-based Pap test vial, and from blood and buccal cell specimens. AmeriPath is one of the first laboratories to offer this test from liquid-based cytology media.

Cystic fibrosis is the most common autosomal recessive genetic disorder found in Caucasian populations. It is characterized by pulmonary and gastrointestinal manifestations of varying severity. Other clinical features include infertility in males and elevated sweat electrolyte levels. Most individuals afflicted with cystic fibrosis experience reduced life expectancy and require lifelong medical care. Although the median survival age is 30 years, there is still no cure for the disease. More than 25,000 Americans have cystic fibrosis, and approximately 850 new cases are diagnosed in this country annually.

The American College of Obstetricians and Gynecologists (ACOG) recommends that genetic screening for cystic fibrosis be offered to all Caucasian couples seeking preconception or prenatal care. Screening should also be made available to couples in other racial and ethnic groups. In addition, individuals with a family history of cystic fibrosis and reproductive partners of individuals who have cystic fibrosis should be tested.

Testing for the most frequently occurring mutations has enabled genetic screening to identify CF carriers. These carriers have a mutation in one of their two copies of the CF gene and are usually unaware of their carrier status. Couples who learn that they both carry the same CF mutation have a one-in-four (25%) chance of having a child with the disease. There are over a thousand documented mutations for cystic fibrosis. However, there are about 25 mutations that show up more often than 1 in 1,000 in Caucasians of Northern European and Ashkenazi Jewish descent. The following table depicts the CF carrier risk, incidence and detection rate for several ethnic groups.

Ethnic Background	Carrier Risk	Incidence of CF	Detection Rate
Caucasian	1 in 29	1 in 3,300	90%
Ashkenazi Jew	1 in 29	1 in 3,300	97%
Hispanic	1 in 46	1 in 9,500	57%
African-American	1 in 62	1 in 15,300	69%
Asian-American	1 in 90	1 in 32,100	N/A

The AmeriPath cystic fibrosis assay detects the 25 mutations and polymorphisms recommended by the ACOG and the American College of Medical Genetics (ACMG). The test consists of multiplex PCR amplification of selected regions of the CF gene followed by probe-specific detection of wild-type and mutant alleles. Polymerase chain reaction allows very small amounts of genetic material to be amplified into billions of copies in just a few hours, thus facilitating the detection of target DNA.

In addition to testing for CF mutations, we also test for HPV, Chlamydia trachomatis and Neisseria gonorrhea from liquid-based cytology media. You can now send a single sample to any AmeriPath laboratory to test for these infectious diseases in conjunction with the Pap test. We also offer prenatal screening for Down syndrome and open neural tube defects. The most advanced maternal serum screen is called the Integrated Test. This test is performed in two stages. The first stage (between 8th and 13th week of pregnancy) involves obtaining a blood sample to measure the concentration of serum pregnancy-associated plasma protein-A (PAPP-A) and a measurement from a nuchal translucency ultrasound. The second stage (between the 15th and 22nd week of pregnancy) involves the taking of another blood sample in order to perform a quad marker screen. The measurements from the first and second stages are then integrated into a single screening result to estimate the risk of a Down syndrome pregnancy. The Integrated Test is revolutionary in the industry with a high detection rate of 94%, saving many pregnant patients from having to undergo unnecessary and more invasive procedures.

The diagnostic quality available at AmeriPath is unparalleled in the industry. Our 68 board-certified cytopathologists routinely pool their medical expertise when consulting on difficult cases and provide personal consultations regarding patient treatment plans and disease management. We have extensive managed care coverage and superior turnaround times. Our enhanced pathology reports feature color-coding and photomicrographs in addition to Pap-to-biopsy correlations. We also provide complimentary patient education materials and a Pap test hotline to notify patients of normal Pap test results.

AmeriPath Inc., is the nation’s largest company focused on providing anatomic pathology, cancer diagnostics, and related healthcare information services to physicians, hospitals, national clinical laboratories and managed-care organizations. The company’s 426 physicians provide medical services through 42 outpatient laboratories, 224 hospital inpatient laboratories and 64 outpatient surgery centers in 21 states.

For additional information about AmeriPath’s Women’s Health Diagnostic Services, please call 1-800-330-6565 to speak with an AmeriPath representative.