A Hemagglutination-Based Semiquantitative Test for Point-of-Care Determination of SARS-CoV-2 Antibody Levels

Robert L. Kruse, Yuting Huang, Alyssa Lee, Xianming Zhu, Ruchee Shrestha, Oliver Laeyendecker, Kirsten Littlefield, Andy Pekosz, Evan M. Bloch, Aaron A.R. Tobian, Zack Z. Wang

Research output: Contribution to journalArticlepeer-review


Serologic point-of-care tests to detect antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are an important tool in the COVID-19 pandemic. The majority of current point-of-care antibody tests developed for SARS-CoV-2 rely on lateral flow assays, but these do not offer quantitative information. To address this, we developed a novel antibody test leveraging hemagglutination, employing a dry card format currently used for typing ABO blood groups. Two hundred COVID-19 patient and 200 control plasma samples were reconstituted with O-negative red blood cells (RBCs) to form whole blood and added to dried viral-antibody fusion protein, followed by a stirring step and a tilting step, 3-min incubation, and a second tilting step. The sensitivities of the hemagglutination test, Euroimmun IgG enzyme-linked immunosorbent assay (ELISA), and receptor binding domain (RBD)-based CoronaChek lateral flow assay were 87.0%, 86.5%, and 84.5%, respectively, using samples obtained from recovered COVID-19 individuals. Testing prepandemic samples, the hemagglutination test had a specificity of 95.5%, compared to 97.3% and 98.9% for the ELISA and CoronaChek, respectively. A distribution of agglutination strengths was observed in COVID-19 convalescent-phase plasma samples, with the highest agglutination score (4) exhibiting significantly higher neutralizing antibody titers than weak positives (2) (P, 0.0001). Strong agglutinations were observed within 1 min of testing, and this shorter assay time also increased specificity to 98.5%. In conclusion, we developed a novel rapid, point-of-care RBC agglutination test for the detection of SARS-CoV-2 antibodies that can yield semiquantitative information on neutralizing antibody titer in patients. The 5-min test may find use in determination of serostatus prior to vaccination, postvaccination surveillance, and travel screening.

Original languageEnglish (US)
Article numbere01186-21
JournalJournal of Clinical Microbiology
Issue number12
StatePublished - Dec 2021
Externally publishedYes


  • SARS-CoV-2
  • antibody
  • hemagglutination
  • point of care
  • red blood cell
  • serology

ASJC Scopus subject areas

  • Microbiology (medical)


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