Specimen Requirements

Specimen type: Peri-rectal swab

1. Obtain specimen from peri-rectal area.

2. Return double swab to sterile Copan culture transport container.

3. Label container with patient’s name (first and last), hospital identification number or date of birth, date and time of specimen collection, and source of specimen.

4. Maintain sterility and forward promptly at ambient temperature only.

Causes for rejection:

1. Inadequately labeled specimen
2. Improper container

3. Insufficient specimen volume
 

Note: Specimen source is required.

LIMITATIONS

1. The peformance of the Cepheid Xpert vanA Assay to detect the vanA gene sequence from microorganisms other than Enterococcus is unknown.

2. Hydrocortisone cream (1% hydrocortisone) and Pepto-Bismol (1-5% bismuth subsalicylate) may interfere with the Xpert vanA assay.

3. The Xpert vanA assay detects vanA gene only, not microorganism; therefore, vanA genes carried by non-enterococci, such as vancomycin-resistant Staphyloccus aureus strains, may also give a positive result.

4. Because the detection of vanA gene sequence is dependent on the number of organisms that contain the vanA gene present in the sample, reliable results are dependent on proper specimen collection, handling, and storage.

5. A positive test result does not necessarily indicate the presence of viable organisms. It is however, presumptive for the presence of vanA containing bacteria.

6. Mutations or polymorphisms in primer or probe binding regions may affect detection of new or unknown vanA variants resulting in a false negative result.

7. Test results may also be affected by concurrent antibiotic therapy, or the number of organisms in the specimen which may be below the limit of detection of the test.