BIOCREDIT COVID-19 Ag kit (Cat.No. G61RHA20)
BIOCREDIT COVID-19 Ag is a lateral flow immunochromatographic assay that adopted dual color system. The test contains colloid gold conjugate pad and a membrane strip pre-coated with antibodies specific to SARS-CoV-2 antigen on the test lines (T). If SARS-CoV-2 antigen is present in the specimen, a visible black band appears on the test lines (T) as antibody-antigen-antibody gold conjugate complex forms. The control line (C) is used for procedural control and should always appear if the test is performed correctly.
- The first commercialization black gold particle technology in the world (high sensitivity and specificity)
- User friendly dual color system (control line: red, test line: black)
- Rapid test time (5-8 min)
- Simple detection of SARS-CoV-2 antigen
BIOCREDIT COVID-19 IgG+IgM Duo (Cat.No. G66RHA25)
BIOCREDIT COVID-19 IgG+IgM Duo is a lateral flow immunochromatographic assay (LFIA) for qualitative detection of IgG and/or IgM antibodies to SARS-CoV-2 in whole blood, serum or plasma specimens. The mouse anti human IgG/IgM- colloidal gold complex (Black-T-Gold) and Rabbit Igx-colloidal gold complex (Red-C-Gold) were coated on a colloidal gold pad. The detection line “C” and “T” were coated with Goat anti-rabbit IgG (C line) and recombinant protein of 2019-nCoV (T line), respectively. If the specimen contains IgG/IgM antibodies to SARS-CoV-2, a colored line appears in the T line area.
- The first commercialization black gold particle technology in the world (high sensitivity and specificity)
- User friendly dual color system (control line: red, test line: black)
- Rapid test time (5-10 min)
- Simple detection of SARS-CoV-2 IgG and IgG
Assays were tested in parallel from the same sample, performed under BSL2 conditions by the same trained technician, who was blinded to RT-PCR results. Assays with visual output were read by two independent observers, conferring with a third in case of disagreement. RT-PCR served as reference method; for samples with discordant result, tests were repeated. Demographic and clinical data were obtained from mandatory notification forms and analysed anonymously. Samples with high viral loads (Ct value ≤ 25) were compared to those with low viral load (Ct values > 25), as previously described [4]. Statistical analysis considered sensitivity, specificity, accuracy, and Kappa coefficient using standard formulas, and Wilson score Confidence Interval at 95% (OpenEpi version 3.01, GraphPad Prism version 8.4.2). Study materials were purchased with laboratory funds, except for Savant RDT, which was provided free-of-charge through a local provider. The study was approved by the institutional review board (Comité Ético Científico, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile) and need for informed consent was waived.
The study included a total of 111 samples from symptomatic patients; 55% were female, with a median age of 40 years. Eighty specimens were RT-PCR positive, representing 22% of all positives during the study period; 31 samples were RT-PCR negative. The median duration from symptom onset to sampling was 2 days (IQR 1–5 days); 88% of specimens (96/109; missing data, n = 2) were taken during the first week of symptoms. Ct values ranged from 10.7 to 37.7 (mean, 22.5). Test performances showed significant differences (Table 1). The evaluation of the Liming Bio kit was stopped after 19 samples, due to its poor results. The other three assays had sensitivities ranging from 16.7% (Savant) to 85% (Bioeasy) and a specificity of 100%. Sensitivities were significantly higher in specimens with high viral loads (Ct values ≤ 25) for RapiGen (84.9%) and Bioeasy (100%) (Table 1). Concordance between these two tests was 82%, while their agreement with Savant was 67% and 50%, respectively. The visual readout of RapiGen was clear, regardless of the intensity of bands. The interpretation of Savant, requiring a UV flashlight provided by the manufacturer, was difficult; its sensitivity might have been higher using an automated reader. Bioeasy cassettes were interpreted by a desktop instrument with options for QR coding, printing, connectivity to laboratory information systems. Overall, the three systems were easy to use and gave a qualitative result in 10–20 minutes.
Although our study directly compared the assays from the same sample material, the off-label use of UTM might have influenced test results. However, some of the assays showed favourable overall sensitivities, suggesting the potential use of antigen-based RDTs as alternative (or adjunct) tools to RT-PCR. As in other studies [3,5], the performance was significantly higher in specimens with high viral loads (Ct ≤ 25). Since culture studies have shown a significant reduction of infectivity with low viral counts (Ct > 24) [6], antigen testing might play a crucial role within strategies aiming to determine the contagiousness of infected individuals.
In conclusion, the study demonstrated a significant heterogeneity of test performance, which might have been influenced by the use of UTM as a non-validated sample material. The results emphasize that rapid antigen detection has the potential to serve as an alternative diagnostic method, especially as a screening tool for patients with high viral loads during early and infective stages of infection.
Description
Lateral flow immunochromatographic assay that adopted dual color system.
For the qualitative detection of SARS-CoV-2 antigen from nasopharyngeal swab specimen.
The test contains colloid gold conjugate pad and a membrane strip pre-coated with antibodies specific to SARS-CoV-2 antigen on the test lines (T).
A visible black band (antibody-antigen-antibody gold conjugate complex) appears on the test lines (T) If SARS-CoV-2 antigen is present in the specimen.
The control line (C) shows that test is performed correctly.
Evaluated with panel specimen (n = 75) by PCR
Sensitivity: 90,2 %
Specificity: 100 %
Go To- Genprice
Applications
COVID-19, Nasopharyngeal swabs
Methods
Findings
