Limitations

• The Xpert CT/NG Assay has only been validated with the following specimen types, collected with the Cepheid Xpert Swab Specimen or Urine Specimen Collection Kits:
  • Endocervical swabs
  • Patient-collected vaginal swabs
  • Male and female urine
  • Male and female pharyngeal swabs
  • Male and female rectal swabs
• Erroneous test results might occur from improper specimen collection, technical error, sample mix-up, or because the number of organisms are below the limit of detection of the test.
• Careful compliance with the instructions in this insert and to the Swab and Urine Collection Kit instruction documents are necessary to avoid erroneous results.
• False negative results may occur if the organism(s) is present at levels below the analytical limit of detection.
• This test has been validated using the procedures provided in the package insert only. Modification to these procedures may alter the performance of the test and are not permitted.
• Because the detection of CT and NG is dependent on the DNA present in the sample, reliable results are dependent on proper sample collection, handling and storage.
• With endocervical and patient-collected vaginal specimens, assay interference may be observed in the presence of: blood (>1% v/v) or mucin (>0.8% w/v).
• With urine specimens, assay interference may be observed in the presence of: blood (>0.3% v/v), mucin (>0.2% w/v), bilirubin (>0.2 mg/mL), or Vagisil feminine powder (>0.2% w/v).
• Collection and testing of urine specimens with the Xpert CT/NG Assay is not intended to replace cervical exam and endocervical sampling for diagnosis of urogenital infection. Other genitourinary tract infections can be caused by other infectious agents.
• The effects of other potential variables such as vaginal discharge, use of tampons, douching, and specimen collection variables have not been determined.
• A negative test result does not exclude the possibility of infection because test results may be affected by improper specimen collection, technical error, specimen mix-up, concurrent antibiotic therapy, or the number of organisms in the specimen which may be below the sensitivity of the test.
• The Xpert CT/NG Assay should not be used for the evaluation of suspected sexual abuse or for other medico-legal indications. Additional testing is recommended in any circumstance when false positive or false negative results could lead to adverse medical, social, or psychological consequences.
• The Xpert CT/NG Assay provides qualitative results. No correlation can be drawn between the magnitude of the Ct value and the number of cells in an infected sample.
• The predictive value of an assay depends on the prevalence of the disease in any particular population.
• Positive results may be observed after successful antibiotic treatment due to target nucleic acids from residual non-viable chlamydia.
• Xpert CT/NG Assay performance has not been evaluated in patients less than 14 years of age.
• Xpert CT/NG Assay performance has not been evaluated in patients with a history of hysterectomy.
• The patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated.
• The Xpert CT/NG Assay has not been validated for use with vaginal swab specimens collected by patients at home. The patient-collected vaginal swab specimen application is limited to health care facilities where support/counseling is available to explain procedures and precautions.
• The Xpert CT/NG Assay has not been evaluated with patients who are currently being treated with antimicrobial agents active against CT or NG.
• As with many diagnostic tests, results from the Xpert CT/NG Assay should be interpreted in conjunction with other laboratory and clinical data available to the physician.
• Mutations or other changes within the regions of bacterial genome covered by the primers and/or probes in the Xpert assay may result in failure to detect target organisms.