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Chlamydia trachomatis and Neisseria gonorrhoeae Detection by Nucleic Acid Amplification

CT, NAAT, NG, GC, STI, STD

Test Codes

EPIC: LAB6531, Beaker: ICNG

Department

Molecular Pathology

Instructions

Nucleic Acid Amplification testing (NAAT) is the preferred option for the detection of Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng). Swabs (urethral, endocervical), urine, and ThinPrep^® PreservCyt liquid-based cytology specimens are acceptable for testing. ThinPrep^® PreservCyt specimens offer the patient and physician an efficient means to perform Ct and Ng testing in conjunction with routine cytology and HPV testing as clinically indicated.

Specimen Collection Criteria

Collect: Swab, urine, or ThinPrep^® PreservCyt specimen, as described below:

SWABS:

Vaginal / Endocervical (Female):

• Preferred specimen: Roche Cobas^® PCR Female Swab Specimen Collection Kit.
• Also acceptable: Swab specimen in UVT or UTM Transport Medium.

Throat, Rectum or Eye sources (Male or Female): 

• Collect swab in UVT or UTM Transport media.

URINE (Male or Female):  

Preferred specimen: First void urine in Roche Cobas^® PCR Urine Sample Kit. 

Also acceptable:

• First void clean catch urine in a sterile collection container or yellow top urine tube. (Minimum: 5.0 mL)
• Midstream urine in a sterile container or yellow top urine tube. Midstream specimens have decreased clinical sensitivity and are of limited diagnostic value. (Minimum: 5.0 mL)

Chlamydia trachomatis and Neisseria gonorrhoeae tests MUST be ordered at the time of collection.

Add-on tests CANNOT be performed on urine specimens following testing on other Instrumentation (i.e., urinalysis).

ThinPrep^® PRESERVCYT LIQUID BASED CYTOLOGY (Female endocervical):

• Chlamydia trachomatis and Neisseria gonorrhoeae tests MUST be ordered at the time of collection.
• Add-on tests CANNOT be performed once the ThinPrep^® specimen has been processed for cytology and/or HPV testing.
• Chlamydia trachomatis and Neisseria gonorrhoeae test results WILL be reported separately, and NOT as a component of the combined PAP/HPV report. 

Physician Office/Draw Specimen Preparation

• Swabs and urine collected in Cobas^® PCR media can be stored and transported at room temperature (20-26°C or 68-78.8°F)
• Unpreserved urine samples must be refrigerated (2-8°C or 36-46°F)
• ThinPrep^® specimens can be stored at room temperature (20-26°C or 68-78.8°F)

Preparation for Courier Transport

Transport: Swabs and urine collected in Cobas^® PCR media can be stored and transported at room temperature (20-26°C or 68-78.8°F). Unpreserved/neat urine samples must be refrigerated (2-8°C or 36-46°F).

Rejection Criteria

Inpatient Specimen Preparation

Specimens should be sent to the main Laboratory if received at Royal Oak. Specimens received at Farmington Hills should be sent to microbiology.

Storage

Specimen Stability for Testing:

Roche Cobas^® PCR Media Swab Sample Kit – Vaginal / Endocervical Swabs
Room Temperature (20-26°C or 68-78.8°F): 12 months
Refrigerated (2-8°C or 36-46°F): 12 months
Frozen (-20°C/-4°F or below): Unacceptable

Swab Specimens in UVT or UTM Transport Medium
Room Temperature (20-26°C or 68-78.8°F): 2 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): Unacceptable

Roche Cobas® PCR Urine Sample Kit
Room Temperature (20-26°C or 68-78.8°F): 12 months
Refrigerated (2-8°C or 36-46°F): 12 months
Frozen (-20°C/-4°F or below): Unacceptable

Unpreserved / Neat Urine Specimens
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

ThinPrep^® PreservCyt Specimens
Room Temperature (20-26°C or 68-78.8°F): 12 months
Refrigerated (2-8°C or 36-46°F): 12 months
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

UVT or UTM Transport Medium: Refrigerated (2-8°C or 36-46°F): 7 days

Roche Cobas® Swab or Urine Collection: Room Temperature (20-26°C or 68-78.8°F): 7 days

ThinPrep^® PreservCyt Specimens Room Temperature (20-26°C or 68-78.8°F): 6 weeks

Laboratory

Royal Oak Clinical Molecular Pathology Laboratory

Performed

Monday – Saturday.
Results are usually available within 24-48 hours of receipt in the Laboratory (excluding weekends and holidays).

Reference Range

Chlamydia trachomatis not detected.
Neisseria gonorrhoeae not detected.

Test Methodology

Nucleic acid amplification testing was performed using the FDA-cleared Cobas^® CT/NG v2.0 test (Roche Molecular Systems, Inc.) on the Cobas^® 4800 System.

Interpretation

By report.

Clinical Utility

The presence or absence of Chlamydia trachomatis or Neisseria gonorrhoeae can be assessed in genitourinary specimens using DNA-based nucleic acid amplification technology, which has been shown to be more sensitive than culture. This test may be used for diagnostic or screening purposes for symptomatic or asymptomatic patients.

Reference

1. Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR 2015 64(3):55-68.

CPT Codes

87491, 87591.

Contacts

Last Updated

4/16/2024