Each year, close to four million cases of chlamydia and one million cases of gonorrhea occur in the United States. Coinfection with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) is not uncommon. In fact, up to half of patients diagnosed may be infected with both pathogens and, therefore, it is important to test all sexually active individuals for both CT and GC. Further, the complications that can result from untreated chlamydia and gonorrhea can be serious. Recent CDC recommendations call for expanded chlamydia testing. It is recommended that all sexually active adolescent women be screened for chlamydia at least once a year. Close to half (46%) of chlamydia cases occur in women ages 15-19 and another one third (33%) of infections occur in females between the ages of 20-24. Young individuals are also at an increased risk for gonorrhea. In fact, seventy-five percent (75%) of all reported cases occur in individuals between the ages of 15 to 29 years.

For over a decade, Gen-Probe has been a leader in nucleic acid probe technology for the diagnosis of infectious disease. The company introduced the first DNA probe assays for CT and GC in 1988 and these assays remain the standard of choice in STD testing.

Use:
The APTIMA COMBO 2 Assay is a second generation nucleic acid amplification test that uses target capture for in vitro qualitative detection and differentiation of rRNA from CT and GC. The assay uses a family of Gen-Probe's proven technologies including target capture (TC), Transcription-Mediated Amplification (TMA) and Dual Kinetic Assay (DKA). This is the same family of technologies used to screen the nation's blood supply.

Features/Benefits:

* This second generation test was developed to address the limitations of first generation amplified tests. The APTIMA COMBO 2 Assay virtually eliminates inhibition problems and cross-reactivity, offers multiplex detection and differentiation and also improves workflow and throughput.
* The testing solution is cost-effective by providing two results from one sample and also increases laboratory efficiency with single tube testing.
* Use of the assay provides clinicians and laboratorians with the appropriate tools to be able to significantly reduce the prevalence and incidence of CT and GC infections in sexually active individuals as well as prevent their serious and costly seqeulae.
* The sensitivity of Gen-Probe's test has been shown to be superior to culture and direct specimen tests. The greater sensitivity of the test permits the use of specimens other than endocervical swabs for women and urethral swabs for men. It is the only assay with urine specimen sensitivity equivalent to swab specimen. Additionally, excellent sensitivity and specificity has been demonstrated with ThinPrep liquid Pap specimens in the APTIMA COMBO 2 Assay.

Sensitivity Specificity
CT 95.9% 98.2%
GC 97.8% 98.9%

References

1. Eng, TR et al. 1999. Prevention of sexually transmitted diseases. A model for overcoming barriers between managed care and public health. Am J Prev Med. 16:60-69.
2. Centers for Disease Control and Prevention. Morbid Mortal Weekly Rep. 2002;51(15):1-39.
3. Centers for Disease Control and Prevention. 2000. Gonorrhea - United States, 1998. Morbid Mortal Weekly Rep. 49:538-542.
4. Washington AD, Browner WS, Korenbort CC. Cost-effectiveness of combined treatment for endocervical gonorrhea considering co-infection with Chlamydia trachomatis. JAMA. 1987;257:2056-2060.