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Chlamydia trachomatis DNA Detection, Cervix or Urethral
|In House Availability||Performed Monday, Wednesday, Friday on day shift|
|Method||Strand Displacement Amplification|
|Collection Instructions||Swab collection kits are available from Microbiology Processing at Parnassus (x3-1314) or Mount Zion (415-885-7845). Do not use expired swab collection kits.
Endocervical swab collection: Use Female (pink) BDProbeTec collection kit.
1. Remove excess mucus from the cervical os with the large-tipped cleaning swab and discard.
2. Insert the small-tipped swab into the cervical canal and rotate for 15-30 sec.
3. Withdraw the swab carefully. Avoid contact with the vaginal mucosa.
4. Uncap the Diluent tube and fully insert the small-tipped swab into this tube.
5. Break the shaft of the swab at the score mark. Use care to avoid splashing of contents. Tightly recap the tube containing the swab.
Male urethral swab: Use Male (blue) BDProbeTec collection kit.
1. Insert the swab 2-4 cm into the urethra and rotate for 15-30 sec.
2. Withdraw the swab and place the blue cap/swab into the empty plastic transport tube. Make sure the cap is tightly secured to the tube.
First void urine
1. The patient should not have urinated for at least 1 hour prior to specimen collection.
2. Collect the first 15-20 mL of voided urine (the first part of the stream-NOT MIDSTREAM) in a plastic, preservative-free container.
3. Refrigerate urine until delivered to the laboratory.
|Container type||For swab, use BDProbeTec collection kit only (see Collection Instructions)|
|Amount to Collect||See preferred volume|
|Sample type||Cervical or male urethral swab, First void urine|
|Preferred volume||20 mL urine|
|Min. Volume||15 mL urine|
|UCSF Rejection Criteria||Expired collection kit. Swab not received in appropriate BD Probetec collection kit. Samples other than cervix, male urethral, and first void urine.|
|Processing notes||Refrigerate sample.|
|Synonyms||congenital infection; prenatal infection|
|Stability||Refrigerated 6 days|
|Turn around times||1-5 days|
|Additional information||The DNA detection test is designed only for genital specimens (urethral, urine or endocervical), not for rectal or other nongenital specimens (e.g., conjunctivae); submit a swab in Chlamydia holding medium for culture of nongenital specimens.
This assay is not approved for contact tracing in suspected sexual abuse or any other medicolegal purposes. Some lubricants, spermicidal agents and feminine powder sprays interfere with Chlamydia testing and should not be used prior to specimen collection. Samples containing blood may give false negative or indeterminate results. DNA detection is superior to culture for detecting cervical or urethral infection with C. trachomatis. Testing urine specimens as the sole test for identifying female patients with chlamydial infections may miss infected individuals. 17/100, or 17% of females with C. trachomatis positive cultures had negative results when urine only was tested. The assay manufacturer states that the sensitivity of the assay is 90.7% and the specificity is 96.6%.The positive predictive value at a 2% prevalence rate is 35% and at a 5% prevalence rate is 58%. The negative predictive value at these prevalence rates is > 99%.
|Last Updated||9/18/2012 2:34:33 PM|
If you have additional questions regarding this test, please call: 415-353-1667