Open AccessDevelopment of rapid antigen test prototype for detection of SARS-CoV-2 in saliva samples
Author(s) -
Agnija Kivrane,
Viktorija Igumnova,
Elza Elizabete Liepina,
Dace Skrastiņa,
Ainārs Leončiks,
Zanna Rudevica,
Svjatoslavs Kistkins,
Aigars Reinis,
Anna Zilde,
Andris Kazāks,
Renāte Ranka
Publication year - 2022
Publication title -
upsala journal of medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 41
eISSN - 2000-1967
pISSN - 0300-9734
DOI - 10.48101/ujms.v127.8207
Subject(s) - saliva , medicine , antibody , polyclonal antibodies , virology , gold standard (test) , interquartile range , real time polymerase chain reaction , antigen , covid-19 , coronavirus , virus , reverse transcription polymerase chain reaction , polymerase chain reaction , immunology , biology , gene , infectious disease (medical specialty) , disease , messenger rna , biochemistry
Background: The development of easy-to-perform diagnostic methods is highly important for detecting current coronavirus disease (COVID-19). This pilot study aimed at developing a lateral flow assay (LFA)-based test prototype to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in saliva samples.
Methods: Mice were immunized using the recombinant receptor-binding domain (rRBD) of SARS-CoV-2 virus spike protein. The combinations of the obtained mouse anti-receptor-binding domain (RBD) polyclonal antibodies (PAbs) and several commercial antibodies directed against the SARS-CoV-2 spike protein were used for enzyme-linked immunosorbent assay (ELISA) to select antibody pairs for LFA. The antibody pairs were tested in a LFA format using saliva samples from individuals with early SARS-CoV-2 infection (n = 9). The diagnostic performance of the developed LFA was evaluated using saliva samples from hospitalized COVID-19 patients (n = 111); the median time from the onset of symptoms to sample collection was 10 days (0–24 days, interquartile range (IQR): 7–13). The reverse transcription-polymerase chain reaction (rRT-PCR) was used as a reference method.
Results: Based on ELISA and preliminary LFA results, a combination of mouse anti-RBD PAbs (capture antibody) and rabbit anti-spike PAbs (detection antibody) was chosen for clinical analysis of sample. When compared with rRT-PCR results, LFA exhibited 26.5% sensitivity, 58.1% specificity, 50.0% positive prediction value (PPV), 33.3% negative prediction value (NPV), and 38.7% diagnostic accuracy. However, there was a reasonable improvement in assay specificity (85.7%) and PPV (91.7%) when samples were stratified based on the sampling time.
Conclusion: The developed LFA assay demonstrated a potential of SARS-CoV-2 detection in saliva samples. Further technical assay improvements should be made to enhance diagnostic performance followed by a validation study in a larger cohort of both asymptomatic and symptomatic patients in the early stage of infection.