 |
||||
|
||||
|
||||
|
|
||||||||||||||||
|
||||||||||||||||
|
DNA TEST FOR CHLAMYDIA
LONDON- A new DNA test for Chlamydia trachomatis genitourinary infections in women is substantially more sensitive than other more invasive methods used to identify what is now the most commonly sexually transmitted pathogen in the United States and other western countries, according to the results of a multicenter investigation The new test uses a DNA amplification technique called the ligase chain reaction ( LCR) to identify even minute traces of C. Trachomatis in the urine of potentially affected women. In the four centers in the USA and Canada, its sensitivity for detecting the pathogen was 93.8%, compared to only 65.0% for standard cervical swab testing. For the new test, a small amount ( 15 to 20 ml) of urine is collected during the day and a portion is added to test tubes containing the various reactants for the LCR procedure. They include enzymes which spur DNA synthesis and proliferation, DNA building blocks and DNA probes known to be specific for the Chlamydia trachomatis molecule. After incubation, an antibody immunoassay is used to identify specific amplified gene products from any Chlamydia trachomatis that might be present. Traditionally, chlamydia has been detected by taking swab samples from inside the urethra or the cervix and then culturing any organisms that may be present. The report's authors suggest that the new test could be a cheaper and more effective alternative to the more commonly used cervical swab procedures, which can be very time consuming, frequently uncomfortable for the patient and prone to false negatives. In addition, they note that from 5% to 30% of infected women may be infected only in the urethra and therefore would not be detected by endocervical swab culture. Early detection and treatment of C.trachomatis infections--specially in asymptomatic women--is important because it allows early treatment and can prevent serious complications, such as pelvic inflammatory disease, "ectopic" pregnancies which develop outside the uterus, and infertility. " Once diagnosed, these infections are easily treated with antibiotics and the billions of dollars spent on the infections and their consequences make it clear that control programs would be cost-effective...On the basis of the performance data alone, LCR testing of women's urine samples offers clear advantages over culture of endocervical swab specimens and has potential for use in such a screening program.," the investigators concluded. The study was reported in The Lancet, v. 345, 1/28/95, pp. 213-216.
| |||||||||
|
|||||||||
|
|||||||||
Science Updates Index
