Test Details
Methodology
Electrochemiluminescence immunoassay (ECLIA)
Result Turnaround Time
1 - 3 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This assay is intended for qualitative detection of total antibodies to SARS-CoV-2 nucleocapsid protein in samples collected on or after 15 days post-symptom onset. The test is intended for use as an aid in indentifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection.
Limitations
The performance of this assay has not been established with cadaveric samples or body fluids other than serum and plasma. This test should not be used to diagnose or exclude acute SARS-CoV-2 infection. An assay that directly detects the virus should be used to evaluate individuals for acute COVID-19, particularly those who have been in contact with the virus. The results should always be assessed in conjunction with the patient's medical history, clinical examination and other laboratory data, as applicable.
SARS-CoV-2 IgG antibodies may be below detectable levels in patients who have been exhibiting symptoms for less than 15 days. Samples should only be tested from individuals 15 days or more post-symptom onset. A positive result may not indicate previous SARS-CoV-2 infection. Consider other information, including clinical history and local disease prevalence, in assessing the need for a second but different serology test to confirm an immune response. Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions. False positive results for the Elecsys Anti-SARS-CoV-2 assay may occur due to cross reactivity from pre-existing antibodies or other possible causes. Accumulating evidence suggests that some people who are immunocompromised (have a weakened immune system) are less likely to develop antibodies following the infection with SARS-CoV-2.
This assay has not been validated with immunocompromised patients. The performance characteristics for SARS-CoV-2 antibodies were established when the original B.1 lineage of the Wuhan-Hu-1 strain was prevalent and, due to the propensity of the virus to mutate, new strains emerge with time that may affect the performance of this device and have serious public health implications. This test should not be used for screening of donated blood, plasma, cells or tissues. Positive and negative predictive values are highly dependent on prevalence. The performance of this test has not been established in individuals that have received a COVID-19 vaccine. Samples should not be taken from patients receiving therapy with high biotin doses (i.e., >5 mg/day) until at least eight hours following the last biotin administration.
Custom Additional Information
Current literature suggests that detectable antibodies against SARS-CoV-2 develop approximately eight to 11 days following onset of symptoms. Correlation with epidemiologic risk factors and other clinical and laboratory findings is recommended. A positive serologic result is not diagnostic but indicates that an individual has likely been infected with SARS-CoV-2 and produced an immune response to the virus. It is not known at this time whether detectable antibody correlates with immunity. A negative serologic result indicates that an individual has not developed detectable antibodies at the time of testing. While contingent on a variety of factors, this could be due to testing too early in the course of infection, the absence of exposure to the virus, or the lack of adequate immune response, which can be due to conditions or treatments that suppress immune function.
FDA-authorized Fact sheets for patients and providers can be accessed at the following link: https://www.fda.gov/medical-devices/emergency-situations-medical-devices/emergency-use-authorizations#covid19ivd.
Specimen Requirements
Specimen
Serum
Volume
0.8 mL
Minimum Volume
0.7 mL (Note: This volume does not allow for repeat testing.)
Container
Gel-barrier tube, red-top tube or serum transfer tube
Collection Instructions
If a tube other than a gel-barrier is used, transfer separated serum to a labeled plastic transport tube. Do not freeze gel-barrier tubes (pour off serum first).
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
| Freeze/thaw cycles | Stable x3 |
Storage Instructions
Room temperature
Causes for Rejection
Gross hemolysis, obvious microbial contamination, and/or received outside of specimen and/or storage and/or labeling requirements; heat-inactivated samples; sodium azide-treated samples
References
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 164068 | SARS-CoV-2 Ab, Nucleocapsid | 94762-2 | 164069 | SARS-CoV-2 Ab, Nucleocapsid | 94762-2 | |
| Order Code | 164068 | |||||
| Order Code Name | SARS-CoV-2 Ab, Nucleocapsid | |||||
| Order Loinc | 94762-2 | |||||
| Result Code | 164069 | |||||
| Result Code Name | SARS-CoV-2 Ab, Nucleocapsid | |||||
| UofM | ||||||
| Result LOINC | 94762-2 |