scholarly journals COVID-19 Antibody Detection and Assay Performance Using Red Cell Agglutination

2021 ◽  
Author(s):  
Kshitij Srivastava ◽  
Kamille A. West ◽  
Valeria De Giorgi ◽  
Michael R. Holbrook ◽  
Nicolai V. Bovin ◽  
...  
Keyword(s):  
Human Plasma ◽  
Antibody Detection ◽  
Red Cell ◽  
Healthy Individuals ◽  
Cell Agglutination ◽  
Assay Performance ◽  
Hands On

We recently developed a red cell based assay to detect SARS-CoV-2 antibodies in human plasma. In the current study, we show the hands-on application of this assay in a group of COVID-19 convalescent plasma donors and healthy individuals.

scholarly journals COVID-19 antibody detection and assay performance using red cell agglutination

2021 ◽  
Author(s):  
Kshitij Srivastava ◽  
Kamille A West ◽  
Valeria De Giorgi ◽  
Michael R Holbrook ◽  
Nicolai V Bovin ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Antibody Detection ◽  
Red Cell ◽  
Cell Agglutination ◽  
Perfect Agreement ◽  
Assay Performance ◽  
Serologic Screening ◽  
Antibody Specificities ◽  
Minimum Performance ◽  
Antibody Tests

Red cells can be labelled with peptides from the SARS-CoV-2 spike protein and used for serologic screening of SARS-CoV-2 antibodies. We evaluated 140 convalescent COVID-19 patients and 275 healthy controls using this C19-kodecyte assay. The analytical performance of the new assay was compared with a virus neutralizing assay and 2 commercial chemiluminescent antibody tests (Total assay and IgG assay, Ortho). The C19-kodecyte assay detected SARS-CoV-2 antibodies with a sensitivity of 92.8% and specificity of 96.3%, well within the minimum performance range required by FDA for EUA authorization of serologic tests. The Cohen's kappa coefficient was 0.90 indicating an almost perfect agreement with the Total assay. The Pearson correlation coefficient was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). The limited correlation in assay reaction strengths suggested that the assays may detect different antibody specificities. Our easily scalable C19-kodecyte assay may vastly improve test capacity in blood typing laboratories using their routine setups for column agglutination technique.

scholarly journals COVID-19 Antibody Detection and Assay Performance Using Red Cell Agglutination

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1878-1878
Author(s):  
Willy A. Flegel ◽  
Kshitij Srivastava ◽  
Valeria De Giorgi ◽  
Michael R Holbrook ◽  
Nicolai V Bovin ◽  
...  
Keyword(s):  
Stock Options ◽  
Red Cells ◽  
Spike Protein ◽  
Antibody Detection ◽  
Red Cell ◽  
Plasma Samples ◽  
Peptide Fragments ◽  
Cell Agglutination ◽  
Blood Typing ◽  
Privately Held

Abstract Background. Serologic assays detecting antibodies against the SARS-CoV-2 spike or nucleocapsid proteins have been developed to advance our understanding of the prognosis and clinical course of the COVID-19 disease. We recently developed a red cell agglutination-based assay to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. This assay uses peptide fragments of the SARS-CoV-2 spike protein to label red cells (C19-kodecytes). We performed a clinical evaluation of this C19-kodecyte assay in COVID-19 convalescent plasma (CCP) donors previously assessed with 2 commercial immunoassays and a virus neutralizing assay. Methods. Red cells were coated with peptide fragments of the SARS-CoV-2 spike protein. We tested plasma samples from 140 CCP donors. The results were compared with those of a virus neutralizing assay and 2 commercial chemiluminescent antibody tests: anti-SARS-CoV-2 Total (IgG, IgM and IgA) assay and anti-SARS-CoV-2 IgG assay (Ortho). Inter-rater agreement between the different assays was measured using Cohen's kappa. Specificity was tested with 150 plasma samples, collected in 2008, more than a decade before the COVID-19 outbreak and with 125 plasma samples, collected in 2020 from consecutive healthy volunteer donors, who tested negative for the Ortho Total assay. Testing was performed using the column agglutination technique commonly employed for blood typing. Results. The area under the ROC curve (AUC) for the C19-kodecyte assay reached 0.95 (95% CI: 0.93 - 0.97) with sensitivity of 92.8% (95% CI: 86.9% - 96.3%) and specificity of 96.3% (95% CI: 93.2% - 98.1%). In almost all of the 40 CCP donors with longitudinal data, the antibody concentration decreased during the follow-up, which ranged from 7 to 44 weeks. In the 140 CCP donors, we compared the C19-kodecyte score to the antibody concentrations from the 2 FDA authorized assays (Ortho Total and Ortho IgG) and the titer in the neutralizing assay. There was a positive relationship between the results of all 4 assays. The Spearman's correlation of our assay was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). Conclusions. Sensitivity and specificity of the C19-kodecyte assay were within the minimum performance range required by the FDA for EUA authorization of serology tests. The limited correlation in assay reaction strengths suggested that the assays may be influenced by different antibody specificities. Unlike the other 84 FDA authorized serologic tests for SARS-CoV-2, this C19-kodecyte assay is a simple and rapid test that can be easily established in any blood typing laboratory worldwide using its routine setup for column agglutination or tube technique. The technique could vastly improve assay capacity, particularly in resource limited hospital blood banks. Disclosures Bovin: Kode Biotech: Current Employment, Current holder of stock options in a privately-held company. Henry: Kode Biotech: Current Employment, Current holder of stock options in a privately-held company.

Red cell agglutination, anaemia and a dermatomal rash

2019 ◽  
Vol 48 (11) ◽  
pp. 769-771
Author(s):  
Benjamin O Adeyemi ◽  
Edeghonghon Olayemi ◽  
Mahinath Bandara
Keyword(s):  
Red Cell ◽  
Cell Agglutination

scholarly journals Analytical Characterization of an Enzyme-Linked Immunosorbent Assay for the Measurement of Transforming Growth Factor β1 in Human Plasma

2018 ◽  
Vol 3 (2) ◽  
pp. 200-212 ◽  
Author(s):  
Brendan M Giles ◽  
Timothy T Underwood ◽  
Karim A Benhadji ◽  
Diana K S Nelson ◽  
Lisa M Grobeck ◽  
...  
Keyword(s):  
Growth Factor ◽  
Human Plasma ◽  
Patient Selection ◽  
Transforming Growth Factor ◽  
Sandwich Elisa ◽  
Transforming Growth Factor Β ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Individuals ◽  
Tgf Β1 ◽  
Apparently Healthy

Abstract Background The transforming growth factor β (TGF-β)–signaling pathway has emerged as a promising therapeutic target for many disease states including hepatocellular carcinoma (HCC). Because of the pleiotropic effects of this pathway, patient selection and monitoring may be important. TGF-β1 is the most prevalent isoform, and an assay to measure plasma levels of TGF-β1 would provide a rational biomarker to assist with patient selection. Therefore, the objective of this study was to analytically validate a colorimetric ELISA for the quantification of TGF-β1 in human plasma. Methods A colorimetric sandwich ELISA for TGF-β1 was analytically validated per Clinical and Laboratory Standards Institute protocols by assessment of precision, linearity, interfering substances, and stability. A reference range for plasma TGF-β1 was established for apparently healthy individuals and potential applicability was demonstrated in HCC patients. Results Precision was assessed for samples ranging from 633 to 10822 pg/mL, with total variance ranging from 28.4% to 7.2%. The assay was linear across the entire measuring range, and no interference of common blood components or similar molecules was observed. For apparently healthy individuals, the average TGF-β1 level was 1985 ± 1488 pg/mL compared to 4243 ± 2003 pg/mL for HCC patients. Additionally, the TGF-β1 level in plasma samples was demonstrated to be stable across all conditions tested, including multiple freeze–thaw cycles. Conclusions The ELISA described in this report is suitable for the quantification of TGF-β1 in human plasma and for investigational use in an approved clinical study.

scholarly journals Aleurone flour increases red-cell folate and lowers plasma homocyst(e)ine substantially in man

2005 ◽  
Vol 93 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Michael Fenech ◽  
Manny Noakes ◽  
Peter Clifton ◽  
David Topping
Keyword(s):  
Folic Acid ◽  
Folate Intake ◽  
Red Cell ◽  
Healthy Individuals ◽  
Free Living ◽  
Folate Status ◽  
Placebo Tablet ◽  
Wet Weight ◽  
Baseline Values ◽  
Randomised Controlled

Aleurone flour (ALF) is a rich source of natural folate (>500 μg/100 g wet weight). Our objective was to establish whether intake of ALF in man can significantly improve folate status and reduce plasma homocyst(e)ine. We performed a randomised, controlled intervention, of 16 weeks duration, in free-living healthy individuals (mean age 46–52 years). Participants were assigned to one of three groups: ALF, 175 g bread made with ALF and placebo tablet each day; PCS, 175 g bread made with pericarp seed coat (PCS) flour and placebo tablet each day (low-folate control); or FA, 175 g bread made with PCS flour and tablet containing 640 μg folic acid each day (high-folate control). The daily folate intake contributed by the bread and tablet was 233 μg in the PCS group, 615 μg in the ALF group and 819 μg in the FA group. The number of participants completing all phases of the PCS, ALF and FA interventions was twenty-five, twenty-five and eighteen, respectively. Plasma and red-cell folate increased significantly (P<0·0001) and plasma homocyst(e)ine decreased significantly (P<0·0001) in the ALF and FA groups only. Plasma folate and red-cell folate in the ALF group (mean, 95 % CI) increased from baseline values of 12·9 (9·9, 15·7) nmol/l and 509 (434, 584) nmol/l to 27·1 (22·5, 31·7) nmol/l and 768 (676, 860) nmol/l, respectively. Plasma homocyst(e)ine in the ALF group decreased from 9·1 (8·2, 10·0) μmol/l at baseline to 6·8 (6·2, 7·5) μmol/l after 16 weeks. In conclusion, moderate dietary intake of ALF can increase red-cell folate and decrease plasma homocyst(e)ine substantially.

scholarly journals A haemagglutination test for rapid detection of antibodies to SARS-CoV-2

2020 ◽  
Author(s):  
Alain Townsend ◽  
Pramila Rijal ◽  
Julie Xiao ◽  
Tiong Kit Tan ◽  
Kuan-Ying A Huang ◽  
...  
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
Glycophorin A ◽  
Red Cell ◽  
Special Equipment ◽  
Cell Agglutination ◽  
Haemagglutination Test ◽  
Point Of Care Test ◽  
Laboratory Facilities

ABSTRACTSerological detection of antibodies to SARS-CoV-2 is essential for establishing rates of seroconversion in populations, detection of seroconversion after vaccination, and for seeking evidence for a level of antibody that may be protective against COVID-19 disease. Several high-performance commercial tests have been described, but these require centralised laboratory facilities that are comparatively expensive, and therefore not available universally. Red cell agglutination tests have a long history in blood typing, and general serology through linkage of reporter molecules to the red cell surface. They do not require special equipment, are read by eye, have short development times, low cost and can be applied as a Point of Care Test (POCT). We describe a red cell agglutination test for the detection of antibodies to the SARS-CoV-2 receptor binding domain (RBD). We show that the Haemagglutination Test (“HAT”) has a sensitivity of 90% and specificity of 99% for detection of antibodies after a PCR diagnosed infection. The HAT can be titrated, detects rising titres in the first five days of hospital admission, correlates well with a commercial test that detects antibodies to the RBD, and can be applied as a point of care test. The developing reagent is composed of a previously described nanobody to a conserved glycophorin A epitope on red cells, linked to the RBD from SARS-CoV-2. It can be lyophilised for ease of shipping. We have scaled up production of this reagent to one gram, which is sufficient for ten million tests, at a cost of ∼0.27 UK pence per test well. Aliquots of this reagent are ready to be supplied to qualified groups anywhere in the world that need to detect antibodies to SARS-CoV-2, but do not have the facilities for high throughput commercial tests.

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