Neisseria gonorrhoeae (GC) & Chlamydia trachomatis (CT), NAAT
Test Mnemonic
GCCT
CPT Codes
- 87491 - QTY (1)
- 87591 - QTY (1)
LOINC ®
36902-5
Aliases
- CT Amplification
- GCCAMP
- Gonorrhea Amplification
- Neisseria gonorrhoeae/Chlamydia trachomatis Amplif
- Chlamydia
- Chlamydia Amplification
- CT
- CTAMP
- GC
- GC amplification
- GCAMP
- Gonococcus
- Gonorrhea
- UCT
- UGC
- UGCCT
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| One | Endocervical | APTIMA Collection Unisex swab | Ambient | Ambient | Endocervical Unisex (white tube blue swab): Remove excess mucus from cervical os and surrounding mucosa using the white cleaning swab, then DISCARD. Insert blue swab into the endocervical canal and gently rotate clockwise for 10-30 seconds. Place swab into Aptima transport tube. Snap off swab at the score line, and close the tube tightly. |
| One | Urethral | APTIMA Collection Unisex swab | Ambient | Ambient | Male Urethral Unisex (white tube blue swab): The patient should not have urinated for at least 1 hr prior to sample collection. Insert the blue swab 2-4 cm into the urethra. Gently rotate the swab clockwise for 2-3 seconds in the urethra. Place swab into Aptima transport tube. Snap off swab at the score line, and close the tube tightly. |
| One | Vaginal | Aptima Multitest Collection Kit | Ambient | Ambient | Vaginal Multitest (orange tube pink swab): A vaginal swab is the recommended specimen for female patients who are clinically suspected of having a chlamydial or gonococcal infection. Carefully insert the swab into the vagina about 2 inches past the introitus and gently rotate the swab for 10-30 seconds. Make sure the swab touches the vaginal walls so that moisture is absorbed by the swab. Vaginal swab specimens may be patient-collected in a clinical setting when a pelvic exam is not otherwise indicated (https://www.hologic.com/package-inserts/swab-collection-instructions-vaginal-main-english#4257225834-454981651). Place swab into Aptima transport tube. Snap off swab at the score line, and close the tube tightly. |
| One | Rectal | Aptima Multitest Collection Kit | Ambient | Ambient | Rectal Multitest (orange tube pink swab): Carefully insert the swab into the rectum about 1-2 inches past the anal margin and gently rotate the swab for about 5-10 seconds. Place swab into Aptima transport tube. Snap off swab at the score line, and close the tube tightly. |
| One | Throat | Aptima Multitest Collection Kit | Ambient | Ambient | Throat Multitest (orange tube pink swab): Carefully insert swab into the throat ensuring contact with bilateral tonsils (if present) and the posterior pharyngeal wall, then withdraw the swab without touching the inside of the cheeks or tongue. Place swab into Aptima transport tube. Snap off swab at the score line, and close the tube tightly. |
| 2 mL | Urine, first-catch | APTIMA Urine specimen collection kit | Ambient | Ambient | First-catch urine is the optimal specimen for screening asymptomatic male patients. Urine may also be used for testing any symptomatic patient, but vaginal specimens are preferred when available due to greater test sensitivity. The patient should not have urinated for at least 1 hour prior to specimen collection. The patient should collect first portion of random voided urine (first part of stream) into a sterile, plastic, preservative-free container. Transfer 2 mL of urine into the Aptima urine specimen transport tube using the disposable pipette provided within 24 hours of collection. Close the tube tightly. Work with one specimen at a time. The correct volume of urine has been added when the fluid level is between the black fill lines (window) on the urine transport tube. Do not overfill or underfill the APTIMA Urine transport tube. |
| 2 mL | Urine, first-catch | Sterile container | Ambient | Ambient | First-catch urine is the optimal specimen for screening asymptomatic male patients. Urine may also be used for testing any symptomatic patient, but vaginal specimens are preferred when available due to greater test sensitivity. The patient should not have urinated for at least 1 hour prior to specimen collection. The patient should collect first portion of random voided urine (first part of stream) into a sterile, plastic, preservative-free container. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| Unspecified | Cervical | Cytyc PreservCyt solution (Thin Prep) | Ambient | Ambient | PreservCyt Solution (ThinPrep) is an acceptable specimen when added onto a ThinPrep Pap Test and no dedicated vaginal or endocervical swab specimens are available. It is not a recommended due to lower test sensitivity compared to other specimen types. For this reason, it is not available as a selectable specimen source/type during order entry, only as a laboratory add-on. In order to place an order on this specimen type, you must place a call to lab client services. If consulted prior to specimen collection, lab client services should advise the provider to collect a separate dedicated Vaginal Multitest Swab for optimal test performance characteristics. If consulted after specimen collection, lab client services should assist the provider in placing an add on order with "Fluid, Cervix" as the specimen source, and have cytology perform the aliquot as below prior to cytology testing. Prior to cytology testing and within 30 days of collection, cytology will transfer a 1 mL aliquot into an APTIMA Specimen Transfer Tube. The specimen must have been stored at 2-30C. |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 15⁰C to 30⁰C. Swab in APTIMA transport media: 60 days; Urine in APTIMA transport media: 30 days; Urine unprocessed: 24 hours; ThinPrep PreservCyt solution in APTIMA transport media: 14 days; ThinPrep PreservCyt unprocessed: 30 days |
| Frozen | -20⁰C to -70⁰C Swab in APTIMA transport media: 12 months; Urine in APTIMA transport media: 12 months; Urine unprocessed: Unacceptable; ThinPrep PreservCyt solution in APTIMA transport media: 12 months; ThinPrep PreservCyt unprocessed: Unacceptable |
| Refrigerated | 2⁰C to 8⁰C Swab in APTIMA transport media: 60 days; Urine in APTIMA transport media: 30 days; Urine unprocessed: 24 hours; ThinPrep PreservCyt solution in APTIMA transport media: 30 days; ThinPrep PreservCyt unprocessed: 30 days |
Days Performed
Mon - Sun
Turnaround Time
1 - 4 days
Methodology
| Name | Description |
|---|---|
| Transcription-Mediated Amplification |
Reference Range
| Chlamydia trachomatis (CT) | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Normal | Not detected | ||||
| Neisseria gonorrhoeae (GC) | |||||
| Sex | Age From | Age To | Type | Range | Range Unit |
| Normal | Not detected |
Special Info
Microbiology Preanalytic Guidance: http://portals.ccf.org/plmi/Laboratory-Medicine/Microbiology-Specimen-Collection-Transport-Information. Up to two tests can be run on a single Aptima Multitest Swab specimen (ie. GCCT+TRVAMP) - if specimen sources have been correctly selected, the shared tests will print on the same label. Do not place more than one label on a single collection tube. Common reasons for specimen rejection: 1. Inappropriate collection device for source selected. 2. Transport tubes containing a cleaning swab or more than 1 swab. 3. Overfilled or underfilled urine transport tubes. 4. Collection device expired prior to specimen collection. Related alternative orders: 1. MISCGC: in-house culture to recover GC for susceptibility testing (only suggested following positive NAAT if treatment failure is suspected). 2. NGNAAO, CTNAAO, or CTNGAO: sendout GC, CT, or GC+CT NAAT for non-FDA approved sources including ocular, nasopharyngeal, and peritoneal. 3. CTRACH: sendout CT culture for non-FDA approved sources including ocular, nasopharyngeal, and peritoneal.
Clinical Info
Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) infections are two of the most common sexually transmitted infections (STI) worldwide. CDC STI Treatment Guidelines include testing and screening recommendations for CT and GC and provide guidance on testing methodology and frequency, as well as specimen types for specific patient populations. The CDC recommends the use of nucleic acid amplification tests (NAATs) for the detection of CT and GC in patients with and without symptoms. The Aptima Combo 2 assay is an FDA-cleared second generation NAAT that utilizes target capture, Transcription-Mediated Amplification (TMA), and Dual Kinetic Assay (DKA) technologies. The Aptima Combo 2 assay on the Panther system qualitatively detects CT and/or GC rRNA in clinician-collected endocervical, PreservCyt Solution liquid Pap specimens, vaginal, throat, rectal, and male urethral swab specimens; patient-collected vaginal swab specimens, and female and male urine specimens from symptomatic and asymptomatic individuals. In 2019, novel C. trachomatis variants were discovered which contain point mutations affecting detection by the original version of the Aptima Combo 2 assay. Variant strains of chlamydia with mutations affecting diagnostic test performance have been reported previously and are a natural product of microbial evolution. The updated version of the Aptima Combo 2 assay provides detection coverage for the variant strains of C. trachomatis that emerged in 2019.
Clinical Limitation
1. The performance of the assay has not been evaluated in patients <14 years of age. 2. The assay is not intended for the evaluation of suspected sexual abuse or for other medico-legal indications. For those patients for whom a false positive result may have adverse psycho-social impact, the CDC recommends retesting. 3. Therapeutic failure or success cannot be determined with the assay since nucleic acid may persist following appropriate antimicrobial therapy. 4. A negative result does not preclude a possible infection because results are dependent on adequate specimen collection. Test results may be affected by improper specimen collection, technical error, specimen mix-up, or target levels below the assay limit of detection. 5. First catch female urine specimens are acceptable but may detect up to 10% fewer CT/GC infections when compared with vaginal and endocervical swab specimens. 6. The effects of tampon use, douching, and specimen collection variables have not been assessed for their impact on assay detection.
Clinical Reference
Workowski KA, Bachmann LH, Chan PA, Johnston CM, Muzny CA, Park I, Reno H, Zenilman JM, Bolan GA. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021 Jul 23;70(4):1-187. doi: 10.15585/mmwr.rr7004a1. PMID: 34292926; PMCID: PMC8344968.