ABSTRACT
Public health emergency of SARS-CoV-2 has facilitated diagnostic testing as a related medical countermeasure against COVID-19 outbreak. Numerous serologic antibody tests have become available through an expedited federal emergency use only process. This paper highlights the analytical characteristic of an ELISA based assay by AnshLabs and three random access immunoassay (RAIA) by DiaSorin, Roche, and Abbott that have been approved for emergency use authorization (EUA), at a tertiary academic center in a low disease-prevalence area. The AnshLabs gave higher estimates of sero-prevalence, over the three RAIA methods. For positive results, AnshLabs had 93.3% and 100% concordance with DiaSorin or Abbott and Roche respectively. For negative results, AnshLabs had 69.7% and 73.0% concordance with DiaSorin and Roche or Abbott respectively. All discrepant samples that were positive by AnshLabs and negative by RAIA tested positive by all-in-one step SARS-CoV-2 Total (COV2T) assay performed on the automated Siemens Advia Centaur XPT analyzer. None of these methods, however, are useful in early diagnosis of SARSCoV- 2.
Subject(s)
COVID-19 , Ichthyosis Bullosa of SiemensABSTRACT
The emergence of coronavirus disease 2019 (COVID-19) has become a major global health crisis. Currently, diagnosis is based on molecular techniques, which detect the viral nucleic acids when present at detectable levels. The serum IgG response against SARS-CoV-2 was examined by using an ELISA-based assay. Serum samples, along with nasopharyngeal specimens were collected from various cohorts and analyzed by ELISA and rRT-PCR, respectively. A total of 167 serum samples were tested for serum IgG antibodies against SARS-CoV-2 in outpatient cohorts, 15 (8.9%) were positive by rRT-PCR and the remaining 152 (91%) were negative. We used these data to generate two different assay cutoffs for serum IgG assay and investigated percent concordance with rRT-PCR test results. The emergency department data revealed, out of 151 nasopharyngeal swabs, 4 (2.6%) were positive by rRT-PCR and 18 (11.9%) were positive for serum IgG assay. Among the 18 patients that were positive for serum IgG, 13 (72.2%) exhibited 1-3 symptoms of COVID-19 and 5 (27.7%) patients did not present with any COVID-19 related symptoms, per CDC criteria. All 4 (100%) patients that were positive by rRT-PCR had symptoms of COVID-19 disease. A longitudinal study from the inpatient population suggested there was a sharp increase in the serum IgG titers in 5 patients, a moderate increase in 1 patient and a plateau in 3 patients. Sero-prevalence of COVID-19 disease in pre-procedure patients was 5.5%. Our findings suggest serological tests can be used for appropriate patient triaging when performed as an adjunct to existing molecular testing.