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Test Code CTNG Chlamydia trachomatis and Neisseria gonorrhea (CT/NG) PCR 

Important Note

For cobas® PCR Urine Sample Kit and cobas® PCR Media Dual Swab Sample Kit, call Clinical Microbiology Laboratory at (773) 702-6133

For Aptima Multitest Swab Collection Kit, call Laboratory Service Center at (773) 702-1316    

Patients less than 14 years old require two specimens: PLEASE SEE EPIC ORDER INSTRUCTIONS

  • one cobas® PCR Media Kit
  • one Aptima Collection Kit
Infectious

Specimen and Container/Tube

Specimen Type: Urine, vaginal swab, endocervical swab, oropharyngeal swab, anorectal swab, ocular

Preferred Specimen: cobas® PCR Urine Sample Kit, cobas® PCR Media Dual Swab Sample Kit

Volume

Preferred Volume: 5 mL 

Specimen Stability

Storage Temperature

Stability

Room temperature

(20 - 25°C)

12 months

Refrigerated

(2 - 10°C)

 12 months

Frozen

(-20°C)

not acceptable

Collection Instructions

Specimen Collection: 

 

Urine: Recommended urine sample is first catch urine (first 10 to 50mL of the urine stream)

  1. Transfer first-void urine from a sterile container to the Roche cobas® PCR Urine Sample Kit until the fluid level is between the two black fill lines. The liquid media included in the PCR transport kit must remain inside the container prior to adding sample.
  2. Using the provided disposable pipette, transfer urine from the sterile container to the Roche cobas PCR Urine Sample Kit until the fluid level is between the two black fill lines.
  3. Tightly re-cap the Roche cobas® PCR Urine sample tube, and invert 5 times to mix. 

 

Endocervical:

  1. First use the large woven swab provided in the Roche cobas® PCR Media Dual Swab Sample Kit  to clean and remove excess mucous. Discard the swab after cleaning.
  2. Use only the flocked swab in the cobas® PCR Media Dual Swab Sample Kit to collect endocervical specimens.
  3. Hold flocked swab with the scoreline above your hand and insert into the endocervical canal. Gently rotate the swab 5 times in one direction in the endocervical canal. Do not over-rotate.
  4. Carefully withdraw the swab, avoiding any contact with the vaginal mucosa.
  5. Remove the cap from the cobas® PCR Media Tube.
  6. Lower the swab specimen into the tube until the visible scoreline on the swab shaft is aligned with the tube rim. The bud of the swab should not be submerged into the liquid prior to breaking the shaft.
  7. Carefully leverage the swab against the tube rim to break the swab shaft at the scoreline.
  8. Tightly close the cobas® PCR Media Tube. Discard the top portion of the swab.

 

Ocular (corneal/conjunctiva):

  1. Collect two specmiens using one ne Cobas PCR Media Dual Swab Sample Kit and one Aptima Multitest Swab Collection Kit.
  2. Use only the woven swab in the cobas® PCR Media Dual Swab Sample Kit to collect second Ocular Specimen.
  3. Place collection swabs in each transport tube provided. Snap off swab at score line so swab fits into closed tube.

 

Vaginal, oropharyngeal, anorectal:

  1. Use only the woven swab in the cobas® PCR Media Dual Swab Sample Kit to collect vaginal, anorectal and oropharyngeal swab specimens. Do not use the flocked swab.
  2. The liquid media included in the PCR transport kit must remain inside the container prior to adding sample. A properly collected swab specimen should have a single swab with the shaft broken at the score line.


Specimen Transport: Immediate

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: Collect specimen per standard collection procedure and send to laboratory immediately. If transport is delayed, refrigerate specimens prior to transport.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, incorrect collection container, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Endocervical swab specimens that have both the large woven polyester swab used for cleaning and the flocked swab used to collect the sample inside of the cobas® PCR media tube will be rejected.
  • Swab specimens that contain dry swabs with no liquid inside of the cobas® PCR media tube will be rejected.
  • Swab specimens that contain NO swab or two swabs inside the cobas® PCR media tube will be rejected.
  • Urine samples that are above or below two black lines on the cobas® PCR Media tube will be rejected. If the liquid level is above or below these lines, the specimen has not been collected properly and cannot be used for testing.
  • Specimen containing excess blood (specimen has a red or brown color), it should be discarded and not used for testing.

Reference Values

 

Test

Age

Sex

Reference Range

CTNG PCR

All

All

No DNA detected

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: not available

Routine Turnaround Time: 72 hours

Testing Schedule: Monday - Sunday

Clinical Indications

  • Aid in the diagnosis of chlamydial and gonococcal disease in both symptomatic and asymptomatic individuals

CPT Codes

87799

LOINC Codes

30487799

Methodology

Roche cobas® 6800 Automated PCR

Synonyms/Keyword Search

Chlamydia trachomatis and Neisseria gonorrhea PCR (CT/NG PCR), CTNG PCR (CHLAMYDIA TRACHOMATIS  AND NEISSERIA GONORRHOEAE), GC/CHLAMYDIA, NEISSERIA GONORRHOEAE (GC), PCR, GONORRHOEA PCR, GC SCREEN BY PCR, CHLAMYDIA TRACHOMATIS BY PCR, C TRACHOMATIS SCREEN BY PCR, C. TRACHOMATIS PCR, CT/NG

Last Review Date

09/15/2025