- As the COVID-19 pandemic progresses, there is an increasing need for rapid, accessible assays for SARS-CoV-2 detection. We present a clinical evaluation and real-world implementation of the INDICAID COVID-19 rapid antigen test (INDICAID rapid test).
- A multisite clinical evaluation of the INDICAID rapid test using prospectively collected nasal (bilateral anterior) swab samples from symptomatic subjects was performed. The INDICAID rapid test demonstrated a positive percent agreement (PPA) and negative percent agreement (NPA) of 85.3% (95% confidence interval [95% CI], 75.6% to 91.6%) and 94.9% (95% CI, 91.6% to 96.9%), respectively, compared to laboratory-based reverse transcriptase PCR (RT-PCR) using nasal specimens.
- The INDICAID rapid test was then implemented at COVID-19 outbreak screening centers in Hong Kong as part of a testing algorithm (termed “dual-track”) to screen asymptomatic individuals for prioritization for confirmatory RT-PCR testing.
- In one approach, preliminary positive INDICAID rapid test results triggered expedited processing for laboratory-based RT-PCR, reducing the average time to confirmatory result from 10.85 h to 7.0 h. In a second approach, preliminary positive results triggered subsequent testing with an onsite rapid RT-PCR, reducing the average time to confirmatory result to 0.84 h. In 22,994 asymptomatic patients, the INDICAID rapid test demonstrated a PPA of 84.2% (95% CI, 69.6% to 92.6%) and an NPA of 99.9% (95% CI, 99.9% to 100%) compared to laboratory-based RT-PCR using combined nasal/oropharyngeal specimens.
- The INDICAID rapid test has excellent performance compared to laboratory-based RT-PCR testing and, when used in tandem with RT-PCR, reduces the time to confirmatory positive result. IMPORTANCE Laboratory-based RT-PCR, the current gold standard for COVID-19 testing, can require a turnaround time of 24 to 48 h from sample collection to result.
- The delayed time to result limits the effectiveness of centralized RT-PCR testing to reduce transmission and stem potential outbreaks. To address this, we conducted a thorough evaluation of the INDICAID COVID-19 rapid antigen test, a 20-minute rapid antigen test, in both symptomatic and asymptomatic populations.
- The INDICAID rapid test demonstrated high sensitivity and specificity with RT-PCR as the comparator method.
- A dual-track testing algorithm was also evaluated utilizing the INDICAID rapid test to screen for preliminary positive patients, whose samples were then prioritized for RT-PCR testing. The dual-track method INDICAID COVID test demonstrated significant improvements in expediting the reporting of positive RT-PCR test results compared to standard RT-PCR testing without prioritization, offering an improved strategy for community testing and controlling SARS-CoV-2 outbreaks.
Direct Detection of Feline Coronavirus by Three Rapid Antigen Immunochromatographic Tests and by Real-Time PCR in Cat Shelters
- The aim of this study was the direct detection of feline coronavirus by real-time PCR and by three different rapid immunochromatographic (RIM) tests detecting antigens in faecal samples of shelter cats. Based on sensitivity and specificity calculated for each of the RIM tests, the utility of RIM tests was compared. Seventy faecal samples originating from shelter cats housed in quarantine were examined.
- Out of 70 samples analyzed by real-time PCR, 44 (62.9%) were positive. Significantly more cats (p < 0.05) tested positive than negative. Neither age nor sex of the cats played a significant role (p > 0.05) in the shedding status of the virus.
- The sensitivity of the RIM tests was found to be at low (<35%; RIM tests A and C) to satisfactory level (>50%, RIM test B). The number of virus particles determined by real-time RT-PCR analysis did not significantly correlate with the results detected by any of the RIM tests (p > 0.05). The results of this study indicate that the use of rapid antigen RIM tests in routine screening of FCoV shedding status in shelter cats is limited due to the occurrence of a high number of false negative results.
Antigen Test Positivity After COVID-19 Isolation – Yukon-Kuskokwim Delta Region, Alaska, January-February 2022.
- Isolation is recommended during acute infection with SARS-CoV-2, the virus that causes COVID-19, but the duration of infectiousness varies among individual persons. Rapid antigen test results have been correlated with detection of viable virus (1-3) and might inform isolation guidance, but data are limited for the recently emerged SARS-CoV-2 B.1.1.529 (Omicron) variant.
- On January 5, 2022, the Yukon-Kuskokwim Health Corporation (YKHC) recommended that persons with SARS-CoV-2 infection isolate for 10 days after symptom onset (or, for asymptomatic persons, 10 days after a positive nucleic acid amplification or antigen test result).
- However, isolation could end after 5-9 days if symptoms were resolving or absent, fever was absent for ≥24 hours without fever-reducing medications, and an Abbott BinaxNOW COVID-19 Ag (BinaxNOW) rapid antigen test result was negative.
- Antigen test results and associated individual characteristics were analyzed among 3,502 infections reported to YKHC during January 1-February 9, 2022. After 5-9 days, 396 of 729 persons evaluated (54.3%) had a positive antigen test result, with a declining percentage positive over time.
- In a multivariable model, a positive antigen test result was more likely after 5 days compared with 9 days (adjusted odds ratio [aOR] = 6.39) or after symptomatic infection (aOR = 9.63), and less likely after previous infection (aOR = 0.30), receipt of a primary COVID-19 vaccination series (aOR = 0.60), or after both previous infection and receipt of a primary COVID-19 vaccination series (aOR = 0.17).
- Antigen tests might be a useful tool to guide recommendations for isolation after SARS-CoV-2 infection. During the 10 days after infection, persons might be infectious to others and are recommended to wear a well-fitting mask when around others, even if ending isolation after 5 days.
Impaired detection of omicron by SARS-CoV-2 rapid antigen tests.
- Since autumn 2020, rapid antigen tests (RATs) have been implemented in several countries as an important pillar of the national testing strategy to rapidly screen for infections on site during the SARS-CoV-2 pandemic. The current surge in infection rates around the globe is driven by the variant of concern (VoC) omicron (B.1.1.529).
- Here, we evaluated the performance of nine SARS-CoV-2 RATs in a single-centre laboratory study. We examined a total of 115 SARS-CoV-2 PCR-negative and 166 SARS-CoV-2 PCR-positive respiratory swab samples (101 omicron, 65 delta (B.1.617.2)) collected from October 2021 until January 2022 as well as cell culture-expanded clinical isolates of both VoCs.
- In an assessment of the analytical sensitivity in clinical specimen, the 50% limit of detection (LoD50) ranged from 1.77 × 106 to 7.03 × 107 RNA copies subjected to the RAT for omicron compared to 1.32 × 105 to 2.05 × 106 for delta. To score positive in these point-of-care tests, up to 10-fold (LoD50) or 101-fold (LoD95) higher virus loads were required for omicron- compared to delta-containing samples.
- The rates of true positive test results for omicron samples in the highest virus load category (Ct values < 25) ranged between 31.4 and 77.8%, while they dropped to 0-8.3% for samples with intermediate Ct values (25-30).
Hepatitis B Surface Antigen (HBsAg) ELISA kit, Qualitative, 96 tests, |
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| 4105 | Alpha Diagnostics | 1 Kit |
Human Anti-Smith antigen (Sm) IgG ELISA kit, 96 tests, Quantitative |
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| 3300-100-SMG | Alpha Diagnostics | 1 kit |
Human Anti-Smith antigen/RNP (Sm/RNP) IgG ELISA kit, 96 tests, Quantitative |
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| 3300-110-SRG | Alpha Diagnostics | 1 kit |
Clostridium difficile Toxin/Toxoid A antigen ELISA kit, 96 tests, Quantitative |
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| CDTA-010-96 | Alpha Diagnostics | 1 Kit |
Anthrax Protective Antigen 83 (PA83) Protein ELISA kit, 96 tests, Quantitative Kit |
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| 800-100-P83 | Alpha Diagnostics | 1 Kit |
Zaire Ebola Virus Glycoprotein (EBOV GP antigen) ELISA Kit, 48 tests, Quantitative |
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| AE-320800-48 | Alpha Diagnostics | 1 kit |
Zaire Ebola Virus Glycoprotein (EBOV GP antigen) ELISA Kit, 96 tests, Quantitative |
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| AE-320800-96 | Alpha Diagnostics | 1 kit |
West Nile Virus NS1 Protein (WNV-NS1) antigen ELISA kit, 96 tests, Quantitative |
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| 910-290-NS1 | Alpha Diagnostics | 1 Kit |
Horse Anti-Anthrax Protective Antigen 83 (PA83) IgG ELISA kit, 96 tests, quantitative |
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| 900-145-83G | Alpha Diagnostics | 1 Kit |
Human Anti-Anthrax Protective Antigen 83 (PA83) IgG ELISA kit, 96 tests, quantitative |
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| 900-165-83G | Alpha Diagnostics | 1 Kit |
Sheep Anti-Anthrax Protective Antigen 83 (PA83) IgG ELISA kit, 96 tests, quantitative |
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| 900-170-83G | Alpha Diagnostics | 1 Kit |
Camel Anti-Anthrax Protective Antigen 83 (PA83) IgG ELISA kit, 96 tests, quantitative |
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| 900-180-83G | Alpha Diagnostics | 1 Kit |
Recombivirus PRRSV NP Type 1 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400106-CP5 | Alpha Diagnostics | 1 pk |
Recombivirus PRRSV NP Type 2 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400116-CP5 | Alpha Diagnostics | 1 kit |
Mouse Anti-Anthrax Protective Antigen 83 (PA83) Ig?s ELISA kit, 96 tests, Quantitative |
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| 900-100-83T | Alpha Diagnostics | 1 Kit |
Rabbit Anti-Anthrax Protective Antigen 83 (PA83) Ig?s ELISA kit, 96 tests, quantitative |
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| 900-120-83T | Alpha Diagnostics | 1 Kit |
Monkey Anti-Anthrax Protective Antigen 83 (PA83) Ig?s ELISA kit, 96 tests, quantitative |
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| 900-150-83T | Alpha Diagnostics | 1 Kit |
Human Anti-Anthrax Protective Antigen 83 (PA83) Ig?s ELISA kit, 96 tests, quantitative |
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| 900-160-83T | Alpha Diagnostics | 1 Kit |
Recombivirus PRRSV NSP Type 1 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400136-CP5 | Alpha Diagnostics | 1 pk |
Recombivirus PRRSV NSP Type 2 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400146-CP5 | Alpha Diagnostics | 1 kit |
Rat Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgG ELISA kit, 96 tests, quantitative |
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| 4270 | Alpha Diagnostics | 1 Kit |
Rat Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgA ELISA kit, 96 tests, quantitative |
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| 4270-30-IGA | Alpha Diagnostics | 1 Kit |
Human Anti-Proliferating Cell Nuclear Antigen (PCNA) IgG ELISA kit, 96 tests, Quantitative |
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| 5025 | Alpha Diagnostics | 1 Kit |
Monkey Anti-Proliferating Cell Nuclear Antigen (PCNA) IgG ELISA kit, 96 tests, Quantitative |
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| 5030 | Alpha Diagnostics | 1 Kit |
G. pig Anti-Anthrax Protective Antigen 83 (PA83) Ig?s ELISA kit, 96 tests, quantitative |
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| 900-140-83T | Alpha Diagnostics | 1 Kit |
Human Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgA ELISA kit, 96 tests, quantitative |
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| 4200-30-IGA | Alpha Diagnostics | 1 Kit |
Mouse Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgG ELISA kit, 96 tests, quantitative |
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| 4210 | Alpha Diagnostics | 1 Kit |
Mouse Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgA ELISA kit, 96 tests, quantitative |
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| 4210-30-IGA | Alpha Diagnostics | 1 Kit |
Human Anti-Hepatitis B Surface Antigen IgG (anti-HBsAg) ELISA kit, Quantitative, 96 tests |
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| 4220-AHB | Alpha Diagnostics | 1 Kit |
Mouse CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4/CD152) ELISA Kit, 96 tests, quantitative |
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| 210-220-CA4 | Alpha Diagnostics | 1 Kit |
Human CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4/CD152) ELISA Kit, 96 tests, quantitative |
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| 210-230-CA4 | Alpha Diagnostics | 1 Kit |
Recombivirus PRRSV NP Type 1+2 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400126-CP5 | Alpha Diagnostics | 1 pk |
Recombivirus Foot and mouth disease virus 3AB antigen coated plates for ELISA (5x96 tests) |
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| RV-400771-CP5 | Alpha Diagnostics | 1 pk |
Recombivirus 1+2+3 E2 Protein antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-500181-CP5 | Alpha Diagnostics | 1 pk |
Rabbit Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgG ELISA kit, 96 tests, quantitative |
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| 4240 | Alpha Diagnostics | 1 Kit |
Monkey Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgA ELISA kit, 96 tests, quantitative |
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| 4250-30-IGA | Alpha Diagnostics | 1 Kit |
G. pig Anti-Hepatitis B Surface Antigen (anti-HBsAg) IgG ELISA kit, 96 tests, quantitative |
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| 4260 | Alpha Diagnostics | 1 Kit |
Recombivirus PRRSV NSP Type 1+2 antigen coated plates for ELISA (5x96 tests), Quantitative |
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| RV-400156-CP5 | Alpha Diagnostics | 1 pk |
Mouse Anti-Anthrax Protective Antigen 83 (PA83) IgG-specific) ELISA kit, 96 tests, quantitative |
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| 900-105-83G | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) early antigen (EA) IgA ELISA Kit, 96 tests, quantitative |
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| 510-215-HEA | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) early antigen (EA) IgG ELISA Kit, 96 tests, quantitative |
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| 510-220-HEG | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) early antigen (EA) IgM ELISA Kit, 96 tests, quantitative |
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| 510-225-HEM | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) Early antigen (D) IgG ELISA Kit, 96 tests, quantitative |
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| 510-245-EDG | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) Early antigen (D) IgM ELISA Kit, 96 tests, quantitative |
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| 510-250-EDM | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) Early antigen (D) IgA ELISA Kit, 96 tests, quantitative |
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| 510-255-EDA | Alpha Diagnostics | 1 Kit |
Recombivirus BVDV 1 Erns 1 Erns (BVDV1-Erns) Protein antigen coated plates for ELISA (5x96 tests) |
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Human Anti-Meningitis B Neisserial Heparin Binding Antigen (NHBA) IgG ELISA kit, 96 tests, quantitative |
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| 600-920-HHG | Alpha Diagnostics | 1 kit |
Mouse Anti-Meningitis B Neisserial Heparin Binding Antigen (NHBA) IgG ELISA kit, 96 tests, quantitative |
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Rabbit Anti-Meningitis B Neisserial Heparin Binding Antigen (NHBA) IgG ELISA kit, 96 tests, quantitative |
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Humanized/Human Anti-Anthrax Protective Antigen 83 (PA83) IgG activity ELISA kit, 96 tests, quantitative |
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Urinary Indican Test Kit |
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| I1000N | BioAssay Systems | 20 |
UVC Indicator Cards, pack of 25 |
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| B1450-IC | Benchmark Scientific | 1 each |
Human Anti-Hepatitis B Surface Antigen Pres-S2 (HB-Pre-S2) IgM ELISA kit, 96 tests, quantitative |
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| 4405 | Alpha Diagnostics | 1 Kit |
Human Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgM ELISA kit, 96 tests, quantitative |
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| 4305 | Alpha Diagnostics | 1 Kit |
Mouse Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgG ELISA kit, 96 tests, quantitative |
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| 4310 | Alpha Diagnostics | 1 Kit |
Mouse Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgM ELISA kit, 96 tests, quantitative |
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| 4315 | Alpha Diagnostics | 1 Kit |
Rat Rena-strip Kit, 25 tests |
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| R-RENA-LF-025 | BioAssayWorks | 25 tests |
Monkey Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgM ELISA kit, 96 tests, quantitative |
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| 4355 | Alpha Diagnostics | 1 Kit |
Monkey Anti-Hepatitis B Surface Antigen Pres-S2 (HB-Pre-S2) IgG ELISA kit, 96 tests, quantitative |
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| 4450 | Alpha Diagnostics | 1 Kit |
Monkey Anti-Hepatitis B Surface Antigen Pres-S2 (HB-Pre-S2) IgM ELISA kit, 96 tests, quantitative |
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| 4455 | Alpha Diagnostics | 1 Kit |
Rabbit Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgG ELISA kit, 96 tests, quantitative |
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| 4340 | Alpha Diagnostics | 1 Kit |
Monkey Anti-Hepatitis B Surface Antigen Pres-S1 (HB-Pre-S1) IgG ELISA kit, 96 tests, quantitative |
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| 4350 | Alpha Diagnostics | 1 Kit |
Human Anti-H. Influenzae B (Hib) polyribosyl phosphate (PRP) antigen (vaccine) ELISA Kit, 96 tests, Quantitative |
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| 980-HIB-AG1 | Alpha Diagnostics | 1 Kit |
Human Rena-strip Kit, 25 tests |
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| H-RENA-LF-025 | BioAssayWorks | 25 tests |
Human Anti-Epstein Barr Virus (EBV/HHV-4) virus capsid antigen (VCA) IgA ELISA Kit, 96 tests, quantitative |
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| 510-230-HEA | Alpha Diagnostics | 1 Kit |
Human Anti-Epstein Barr Virus (EBV/HHV-4) virus capsid antigen (VCA) IgG ELISA Kit, 96 tests, quantitative |
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Human Anti-Epstein Barr Virus (EBV/HHV-4) virus capsid antigen (VCA) IgM ELISA Kit, 96 tests, quantitative |
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Free Chlorine Reagent set (25 tests) |
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| HI-701-25 | Scientific Laboratory Supplies | PK25 |
Total Chlorine Reagent set (25 tests) |
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| HI-711-25 | Scientific Laboratory Supplies | PK25 |
Human Anti-Epstein Barr Virus (EBV/HHV-4) Nuclear Antigen 1 (EBNA-1) IgA ELISA Kit, 96 tests, quantitative |
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| 510-200-HEA | Alpha Diagnostics | 1 Kit |
Of note, testing of expanded virus stocks suggested a comparable RAT sensitivity of both VoCs, questioning the predictive value of this type of in vitro-studies for clinical performance. Given their importance for national test strategies in the current omicron wave, awareness must be increased for the reduced detection rate of omicron infections by RATs and a short list of suitable RATs that fulfill the minimal requirements of performance should be rapidly disclosed.