tetano
Editor, Senior Moderator
J Med Microbiol
. 2021 Aug;70(8).
doi: 10.1099/jmm.0.001402.
Effect of multiple freeze-thaw cycles on the detection of anti-SARS-CoV-2 IgG antibodies
Farah M Shurrab[SUP] 1 [/SUP], Duaa W Al-Sadeq[SUP] 1 2 [/SUP], Fathima Amanullah[SUP] 1 [/SUP], Salma N Younes[SUP] 1 [/SUP], Hadeel Al-Jighefee[SUP] 1 3 [/SUP], Nadin Younes[SUP] 1 [/SUP], Soha R Dargham[SUP] 4 5 [/SUP], Hadi M Yassine[SUP] 1 3 [/SUP], Laith J Abu Raddad[SUP] 4 5 6 [/SUP], Gheyath K Nasrallah[SUP] 1 3 [/SUP]
Affiliations
Abstract
Several studies have investigated the effect of repeated freeze-thaw (F/T) cycles on RNA detection for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, no data are available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and 1 negative SARS-CoV-2 IgG sera from 11 participants, in replicates of 5, were subjected to a total of 16 F/T cycles and stored at 4 °C until tested by ELISA. Statistical analysis was performed to test for F/T cycle effect. None of the 10 positive sera became negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random effect linear regression of log (OD) on the number of cycles showed no significant trend, with a slope consistent with zero (B=-0.0001; 95 % CI -0.0008; 0.0006; P-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect SARS-CoV-2 IgG antibodies.
Keywords: COVID-19; IgG; SARS-CoV-2; antibodies; detection; freeze; thaw.
. 2021 Aug;70(8).
doi: 10.1099/jmm.0.001402.
Effect of multiple freeze-thaw cycles on the detection of anti-SARS-CoV-2 IgG antibodies
Farah M Shurrab[SUP] 1 [/SUP], Duaa W Al-Sadeq[SUP] 1 2 [/SUP], Fathima Amanullah[SUP] 1 [/SUP], Salma N Younes[SUP] 1 [/SUP], Hadeel Al-Jighefee[SUP] 1 3 [/SUP], Nadin Younes[SUP] 1 [/SUP], Soha R Dargham[SUP] 4 5 [/SUP], Hadi M Yassine[SUP] 1 3 [/SUP], Laith J Abu Raddad[SUP] 4 5 6 [/SUP], Gheyath K Nasrallah[SUP] 1 3 [/SUP]
Affiliations
- PMID: 34356000
- DOI: 10.1099/jmm.0.001402
Abstract
Several studies have investigated the effect of repeated freeze-thaw (F/T) cycles on RNA detection for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, no data are available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and 1 negative SARS-CoV-2 IgG sera from 11 participants, in replicates of 5, were subjected to a total of 16 F/T cycles and stored at 4 °C until tested by ELISA. Statistical analysis was performed to test for F/T cycle effect. None of the 10 positive sera became negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random effect linear regression of log (OD) on the number of cycles showed no significant trend, with a slope consistent with zero (B=-0.0001; 95 % CI -0.0008; 0.0006; P-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect SARS-CoV-2 IgG antibodies.
Keywords: COVID-19; IgG; SARS-CoV-2; antibodies; detection; freeze; thaw.