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HelpTest Code LAB0108 SARS-CoV-2 PCR
Performing Lab
Arnot Ogden Medical Center Laboratory
Ordering Recommendations
This test is intended for the rapid qualitative detection of nucleic acid from the SARS-CoV-2 virus in nasopharyngeal specimens collected from inidividuals suspected of COVID-19 disease.
Collect
Nasopharyngeal swab collected with Viral Transport kit (red top)
Collection Device
Flocked nasopharyngeal swab and approved Transport Medium (red top)
Available from the Laboratory.
Stability (from collection to initiation)
|
Nasopharyngeal Swab |
Temperature | Duration of Stability |
| Room Temp (15-30C) | Up to 48 hours | |
| 2-8C | Up to 7 days |
Storage/Transport Temperature
|
Nasopharyngeal Swab |
Temperature | Duration of Stability |
| Room Temp (15-30C) | Up to 48 hours | |
| 2-8C | 7 days |
Methodology
Nucleic Acid Amplification
Start Date
5/20/2020
Last Review Date
1/7/2026
Performed
Daily
Reference Interval
Reference Range: Negative
Interpretive Data
| Interpretation | |
| SARS-CoV-2 POSITIVE | SARS-CoV-2 target RNA is detected. |
| SARS-CoV-2 NEGATIVE | SARS-CoV-2 target RNA is not detected. |
- Performance of the Xpert Xpress SARS-CoV-2 has only been established in nasopharyngeal and anterior nasal swab specimens. Specimen types other than nasopharyngeal or anterior nasal swabs may give inaccurate results.
- A false negative result may occur if a specimen is improperly collected, transported or handled. False negative results may also occur if inadequate numbers of organisms are present in the specimen.
- As with any molecular test, mutations within the target regions of Xpert Xpress SARS-CoV-2 could affect primer and/or probe binding resulting in failure to detect the presence of virus.
- This test cannot rule out diseases caused by other bacterial or viral pathogens.
Unacceptable Conditions
- Specimens that are not submitted in the correct viral transport media will be rejected.
- Specimens that do not meet the current laboratory standards for labeling will be rejected.
- Specimens collected using expired collection devices will be rejected.
- Specimens exceeding stability limits will be rejected.
Lab Section
Microbiology
Collection Instructions
Nasopharyngeal Swab Collection Procedure
Insert the swab into either nostril, passing it into the posterior nasopharynx (see Figure 1). Rotate swab by firmly brushing against the nasopharynx several times. Remove and place the swab into a viral transport tube (3 mL). Break swab at the indicated break line and cap the specimen collection tube tightly.
Reported
Same shift
Limitations
● For prescription use only.
● A negative test result does not exclude the possibility of viral or bacterial infection.
● Negative results do not preclude SARS-CoV-2 and should not be used as the sole basis for treatment or other patient management decisions.
● Results from the Xpert Xpress CoV-2 plus test should be correlated with the clinical history, epidemiological data, and other data available to the clinician evaluating the patient.
● The performance of this device has not been assessed in individuals without signs or symptoms of respiratory infection.
● Performance of the Xpert Xpress CoV-2 plus test has only been established in nasopharyngeal swab and anterior nasal swab specimens. Use of the Xpert Xpress CoV-2 plus test with other specimen types has not been assessed and performance characteristics are unknown.
● The performance of the Xpert Xpress CoV-2 plus test has not been specifically evaluated for nasopharyngeal swab and anterior nasal swab specimens from immunocompromised individuals.
● Clinical performance has not been established with all circulating variants but is anticipated to be reflective of the prevalent variants in circulation at the time and location of the clinical evaluation. Performance at the time of testing may vary depending on the variants circulating, including newly emerging strains of SARS-CoV-2 and their prevalence, which change over time.
● Use of this test is limited to personnel who are trained in the procedure. Failure to follow these instructions may result in erroneous results.
● As with any molecular test, mutations within the target regions of Xpert Xpress CoV-2 plus could affect primer and/or probe binding and result in failure to detect the presence of the target virus or newly emerging variants.
● Positive and negative predictive values are highly dependent on prevalence. The likelihood of a negative result being false is higher during peak activity when prevalence of disease is high. The likelihood of a positive result being false is higher during periods when prevalence is moderate to low.
● The performance of this test was validated using the procedures provided in this instructions for use only. Modifications to these procedures may alter the performance of the test.
● Erroneous test results might occur from improper specimen collection; failure to follow the recommended sample collection, handling, and storage procedures; technical error; or sample mix-up. Careful compliance with the instructions in this insert is necessary to avoid erroneous results.
● False negative results may occur if the target virus is present at levels below the analytical limit of detection.
● Viral nucleic acid may persist in vivo, independent of virus infectivity. Detection of analyte target(s) does not imply that the corresponding virus(es) are infectious or are the causative agents for clinical symptoms.
● This test has been evaluated for use with human specimen material only.
● The Xpert Xpress CoV-2 plus test is a qualitative test that reports Ct values for individuals who test positive for SARSCoV-2. These Ct values should not be interpreted as a measure of viral levels.
● The performance of this test has not been established for monitoring treatment of SARS-CoV-2 infection.
● This test has not been established for screening of blood, blood products, or post-mortem specimens for the presence of SARS-CoV-2.
● The effect of interfering substances has only been evaluated for those listed within the labeling. Interference by substances other than those described can lead to erroneous results.
● Mucin (Type I-S) and Fluticasone Propionate may interfere with COVID-19 detection at levels greater than 1.25 mg/mL and 2.5 µg/mL, respectively.
● Cross-reactivity with respiratory tract organisms other than those described herein may lead to erroneous results.
● The E gene targeted by the Xpert Xpress CoV-2 plus test can detect, in addition to SARS-CoV-2, other coronavirus species within the Sarbecovirus subgenus. None of these other coronaviruses are known to currently circulate in the human population.
● The Xpert Xpress CoV-2 plus test has not been validated for the testing of pooled specimens or the screening of specimens from asymptomatic individuals that do not have signs and symptoms of respiratory infection.