Effectively immediately, UCI Laboratories will offer testing for SARS-CoV-2 IgG antibodies on the Diazyme DZ-Lite 3000 platform, an indirect chemiluminescence immunoassay for the qualitative detection of IgG antibodies against SARS-CoV-2.
Background:
Specificity, >97% (manufacturer): In-house studies of 56 pre-COVID and 65 PCR-negative specimens yielded no positive results (100% specificity, n=121 specimens – 95% confidence interval, 97-100%). Specimens were biased towards patients with autoimmune and other viral infections (e.g. HIV and hepatitis). However, known influenza or other coronavirus cases were unavailable, and the manufacturer states that positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.
Sensitivity, >91% (manufacturer): In-house studies of 35 PCR-confirmed cases revealed the following sensitivities: 27% (<7 days after symptom onset, n=4/15), 58% (7-13 days, n=7/12), and 100% (>14 days, n=8/8). For maximal sensitivity, specimens should be collected at least 14 days after symptom onset. Negative results do not preclude infection, and for patients with more recent symptoms, molecular testing for SARS-CoV-2 or follow-up antibody testing should be considered.
COVID-19 experience and data remain insufficient for precise calculation of specificity and sensitivity values; ongoing validation with additional specimens will be performed. Per the CDC, positive results should not be interpreted as evidence of immunity. Results from antibody testing should not be used as the sole basis for diagnosing, informing, or excluding SARS-CoV-2 infection or infection status. This test should not be used for the screening of donated blood.
FDA Emergency Use Authorization (EUA) for this test remains pending. This test is therefore considered a laboratory developed test (LDT) whose performance characteristics were determined by UCI Laboratories, which is certified under the Clinical Laboratory Improvement Amendments (CLIA) for high-complexity testing.
Effective date: April 22, 2020
Specimen requirement:
Specimen tube: Serum (Red, Gold) or Plasma (Green, Lavender/Pink)
Minimum volume: 1 ml
Reporting:
REACTIVE
NONREACTIVE
Test code:
COVIG
Minimum Stability (after separation from cells):
Ambient: 2 hours
Refrigerated: 72 hours
If longer storage is required, freeze at -20˚C or colder.
Some tests may have extended stability beyond stated minimum limits. See directory for details.
Turnaround time (TAT):
STAT: N/A
Routine: <12 hours
Set Up Days: Daily
Rejection criteria:
Specimens containing particulate matter, lipemic or hemolyzed specimens, specimens that exceed stated stability, unlabeled/mislabeled/mismatched specimens, specimens submitted in leaking containers, or specimens received with insufficient amounts for testing.
References:
- https://www.cdc.gov/coronavirus/2019-ncov/faq.html
Last updated on April 17, 2020
- https://www.fda.gov/medical-devices/emergency-situations-medical-devices/faqs-diagnostic-testing-sars-cov-2#whatif
Last updated on April 17, 2020
A summary of all tests offered by our laboratory services can be found here:
http://www.pathology.uci.edu/services/index.asp
Sincerely,
Bridgit O. Crews, PhD, DABCC
Director
Clinical Chemistry, Toxicology, and Point-of-Care Testing
Edwin S. Monuki, MD, PhD
CLIA Director
UCI Laboratories |
