In contrast, lateral flow immunoassays (LFAs) are an inexpensive testing solution that can be used at point-of-care settings, do not require laboratory equipment, and can generate results quickly. However, the performance of LFA-based SARS-CoV-2 rapid antigen tests in community testing settings can vary significantly .
In this study, we evaluated the clinical performance of the LFA-based INDICAIDCOVID-19 Rapid Antigen Test (INDICAID Rapid Test) by PHASE Scientific International Ltd. A prospective multi-site clinical study was performed in symptomatic patient populations in point-of-care (POC) community testing sites in the United States. The performance of the INDICAID Rapid Test was also evaluated in COVID-19 outbreak screening centers in Hong Kong as a part of an algorithm testing approach (termed “Dual-Track”) to screen for COVID-19 positive patients prior to RT-PCR testing in asymptomatic patient populations.
The global SARS-CoV-2 pandemic has continued despite implementation of significant public health measures .
Over 155 million worldwide cases of COVID-19 and over 3 million COVID-19 deaths have been reported as of May 2021. Rapid identification of SARS-CoV-2 infection, patient isolation, and contact tracing are essential for disease containment .
The current gold standard for detecting SARS-CoV-2 is reverse-transcriptase polymerase chain reaction (RT-PCR) . While RT-PCR can detect nucleic acids from SARS-CoV-2 with high sensitivity, RT-PCR requires equipment, special training, and can take days until results are available following sample collection . Due to the uniquely high transmissibility of SARS-CoV-2 (basic reproductive number R0 of 2.87), long turnaround times for results may lead to a high number of avoidable transmissions .
Description of the INDICAID COVID-19 Rapid Antigen Test
The INDICAID Rapid Test by PHASE Scientific is a LFA designed for the qualitative detection of SARS-CoV-2 nucleocapsid protein in nasal swab samples. The test produces a simple readout within 20 minutes with the presence of a visible test line to indicate detection of the SARS-CoV-2 antigen. In contrast to other reader-based rapid antigen platforms, the INDICAID Rapid Test achieves results without any additional equipment, power source, or training.
Sample collection and procedure of the INDICAID COVID-19 Rapid Antigen Test
To conduct an INDICAID Rapid Test, a nasal swab sample is collected by inserting the provided swab 1 inch into the nasal cavity. The swab is rubbed against the inside walls of both nostrils 5 times in a large circular path. The swab is then dipped into a buffer solution to elute the sample. Finally, three drops of the buffer solution-specimen mix are applied to the LFA test device. After 20 minutes, the user observes the test device for the presence or absence of a test line that indicates detection of the SARS-CoV-2 antigen. An Internal Quality Control line is included to indicate whether the test has been performed correctly.
Prospective multi-site clinical evaluation of INDICAID™ COVID-19 Rapid Antigen Test
Populations and study locations
Between November 30, 2020 and January 8, 2021, study participants were enrolled at two US clinical sites, CityHealth Urgent Care San Francisco, CA and CityHealth Urgent Care Oakland, CA.
As part of the inclusion criteria, study participants were required to be at least 5 years of age and report onset of at least two of the following COVID-19 symptoms within 5 days or less: fever or chills, fatigue, sore throat, congestion or runny nose, cough, headache, diarrhea, shortness of breath or difficulty breathing, muscle or body aches, new loss of taste or smell, nausea, or vomiting. A patient enrichment strategy was implemented to increase the rate of SARS-CoV-2 positive participants enrolled at the CityHealth Urgent Care Oakland, CA site. For this strategy, patients presenting at the clinic were first tested by CityHealth Urgent Care staff, as part of the standard-of-care, with an FDA EUA rapid antigen test (Quidel Sofia SARS Antigen FIA) to pre-screen potential subjects prior to study enrollment. CityHealth Urgent Care staff were asked to identify patients with preliminary positive or negative results for study screening. The trained study operators, blinded to the original patient standard-of-care result, performed specimen collection, processing, and testing. An equal number of positives and negatives were pre-screened by the CityHealth Urgent Care staff at the CityHealth Urgent Care Oakland, CA site. Five unique study operators with varying healthcare backgrounds (licensed medical assistants and registered nurses) conducted the study between the two sites.
Between February 6, 2021 and March 9, 2021, study participants were enrolled at a third US clinical testing site (San Fernando Recreation Park in San Fernando, CA) who were at least 5 years of age and reported at least one of the COVID-19 symptoms listed above. Five unique study operators with varying healthcare backgrounds (licensed medical assistants and registered nurses) conducted the study at the San Fernando, CA site.
Testing procedure
Following the standard of care, patients were asked to provide a total of three nasal swab samples: a self-collected and observed nasal swab sample, followed by a second and third nasal swab sample that were collected by the health care provider (HCP). For the self-collected sample, the HCP provided specimen collection instructions and observed the specimen collection by the patient. The order of the second and third HCP-collected samples was randomized for testing with the investigational antigen test and a comparator method to ensure that bias was not introduced due to unequal distribution of viral material. Immediately after sample collection, the samples for the RT-PCR reference method were stored in viral transport media, while the other two nasal swabs were tested directly with the INDICAID Rapid Test according to the instructions for use (IFU).
INDICAID Rapid Test samples were tested immediately on-site after collection with no storage in accordance with the manufacturer’s protocol. Results of the INDICAID Rapid Test were interpreted by the test operators and recorded as “Positive,” “Negative”, or “Invalid” based on the visual presence or absence of the control and test lines on the developed test strip. Test results were recorded after 20 minutes of assay development by one individual operator per participant.
SARS-CoV-2 Rapid Antigen Test Nasal |
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9901-NCOV-03G | Roche Diagnostics | 25 Tests/Kit | 94 EUR |
SARS-CoV-2 Antigen Rapid Test Kit |
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CoV2Ag-1 | UnScience | 1T | 8 EUR |
SARS-CoV-2 Antigen Rapid Test Kit |
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CoV2Ag-25 | UnScience | 25T/kit | 35 EUR |
Human Streptococcus Pneumoniae (SP) Antigen Rapid Test Kit |
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abx092096-20tests | Abbexa | 20 tests | 398 EUR |
NDV rapid test kit |
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RG15-03 | Bionote | 1 box | 139.05 EUR |
IBD rapid test strip |
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RG15-04 | Bionote | 10 boxes | 148 EUR |
Rabies rapid test strip |
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RG18-01 | Bionote | 10 boxes | 151.92 EUR |
Melamine Rapid Test Kit |
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abx092011-50tests | Abbexa | 50 tests | 370 EUR |
Accu-Tell COVID-19 IgG/IgM Rapid Test |
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GEN-B352-20tests | Accu test | 20 tests | 236 EUR |
Accu-Tell COVID-19 IgG/IgM Rapid Test |
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GEN-B352-40tests | Accu test | 40 tests | 321 EUR |
Avian Influenza Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092015-40tests | Abbexa | 40 tests | 432 EUR |
Newcastle Disease Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092016-40tests | Abbexa | 40 tests | 432 EUR |
Human Chlamydia Trachomatis Antigen Rapid Test Kit (Colloidal gold) |
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abx092049-20tests | Abbexa | 20 tests | 230 EUR |
Coronavirus (SARS-Cov-2) Antigen Rapid Test Device (Saliva) |
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IOV87952 | INVBIO | 20T/kit | 39 EUR |
Rapid Leishmania Ab Test Kit |
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RB2104 | Bionote | 1 box | 127 EUR |
Rapid PED Ag Test Kit |
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RG14-01 | Bionote | 1 box | 159.9 EUR |
Melamine (MEL) Rapid Test Kit |
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abx092057-50tests | Abbexa | 50 tests | 370 EUR |
Clenbuterol (CLE) Rapid Test Kit |
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abx092058-50tests | Abbexa | 50 tests | 244 EUR |
Ractopamine (RAC) Rapid Test Kit |
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abx092059-50tests | Abbexa | 50 tests | 244 EUR |
Salbutamol (SAL) Rapid Test Kit |
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abx092060-50tests | Abbexa | 50 tests | 244 EUR |
Tetracycline (TCs) Rapid Test Kit |
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abx092063-50tests | Abbexa | 50 tests | 398 EUR |
Sulfonamides (Sas) Rapid Test Kit |
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abx092064-40tests | Abbexa | 40 tests | 398 EUR |
Quinolones (QNs) Rapid Test Kit |
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abx092065-40tests | Abbexa | 40 tests | 398 EUR |
Ciprofloxacin (CPFX) Rapid Test Kit |
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abx092066-50tests | Abbexa | 50 tests | 398 EUR |
Quinolones (QNs) Rapid Test Kit |
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abx092067-40tests | Abbexa | 40 tests | 398 EUR |
Brucella Antibody Rapid Test Kit |
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abx092069-40tests | Abbexa | 40 tests | 356 EUR |
Procalcitonin rapid test (Colloidal Gold) |
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abx095264-80Units | Abbexa | 80 Units | 954 EUR |
Avian Influenza H5 Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092014-40tests | Abbexa | 40 tests | 488 EUR |
Avian Influenza H7 Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092017-40tests | Abbexa | 40 tests | 432 EUR |
Anigen Rapid FIV Ab Test Kit |
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RB22-01-DD | Bionote | 10 tests/Kit | 129.8 EUR |
Rapid Bovine Brucella Ab Test Kit |
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RB23-01-DD | Bionote | 1 kit/10 tests | 151.79 EUR |
Rapid Bovine TB Ab Test Kit |
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RB23-02-DD | Bionote | 1 box | 128.4 EUR |
Rapid FMD NSP Ab Test Kit |
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RB28-02-DD | Bionote | 1 box | 135.4 EUR |
Ag rapid CDV Ag Test Kit |
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RG11-03 | Bionote | 1 box | 138.2 EUR |
Rapid TGE/PED Ag Test Kit |
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RG14-03 | Bionote | 1 box | 240.85 EUR |
Ag Rapid AIV Ag Test Kit |
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RG15-01 | Bionote | 1 box/30 tests | 267 EUR |
Ag Rapid H5AIV Ag test kit |
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RG15-05 | Bionote | 1 box | 463 EUR |
Clenbuterol Rapid Test Kit (Colloidal gold) |
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abx092040-50tests | Abbexa | 50 tests | 272 EUR |
Ractopamine Rapid Test Kit (Colloidal gold) |
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abx092042-50tests | Abbexa | 50 tests | 300 EUR |
Salbutamol Rapid Test Kit (Colloidal gold) |
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abx092043-50tests | Abbexa | 50 tests | 342 EUR |
Chloramphenicol Rapid Test Kit (Colloidal gold) |
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abx092045-50tests | Abbexa | 50 tests | 356 EUR |
Quinolones Rapid Test Kit (Colloidal gold) |
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abx092046-50tests | Abbexa | 50 tests | 537 EUR |
Sulfonamides Rapid Test Kit (Colloidal gold) |
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abx092047-50tests | Abbexa | 50 tests | 551 EUR |
Tetracycline Rapid Test Kit (Colloidal gold) |
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abx092048-50tests | Abbexa | 50 tests | 467 EUR |
Zearalenone Rapid Test Kit (Colloidal gold) |
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abx092051-50tests | Abbexa | 50 tests | 411 EUR |
Deoxynivalenol Rapid Test Kit (Colloidal gold) |
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abx092052-50tests | Abbexa | 50 tests | 467 EUR |
Deoxynivalenol Rapid Test Kit (Colloidal gold) |
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abx092053-50tests | Abbexa | 50 tests | 467 EUR |
Aflatoxin Rapid Test Kit (Colloidal gold) |
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abx092054-50tests | Abbexa | 50 tests | 398 EUR |
Zearalenone Rapid Test Kit (Colloidal gold) |
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abx092056-50tests | Abbexa | 50 tests | 425 EUR |
Goat Brucella Antibody Rapid Test Kit |
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abx092070-40tests | Abbexa | 40 tests | 356 EUR |
Cow Brucella Antibody Rapid Test Kit |
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abx092071-40tests | Abbexa | 40 tests | 356 EUR |
Pig Parvovirus Antibody Rapid Test Kit |
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abx092074-50tests | Abbexa | 50 tests | 321 EUR |
Fetal Fibronectin rapid test (Colloidal Gold) |
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abx095261-80Units | Abbexa | 80 Units | 1553 EUR |
Dynamiker Monkeypox Virus Ag Rapid Test |
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DNK-2114-1 | Dynamiker Biotechnology | 20 tests | 585 EUR |
2019-nCoV IgG/IgM Rapid Test Cassette (Whole Blood/Serum/Plasma) |
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GEN-402-25tests | All test | 25 tests | 244 EUR |
TruStrip RDT Anthrax Protective antigen 83 (PA83) Rapid Test cards, 25/pk |
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800-100-RDT-25 | Alpha Diagnostics | 1 pk | 408 EUR |
Ag Rapid Bov. TB Ab Test Kit |
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RB23-02 | Bionote | 1 box | 145 EUR |
Ag Rapid FMD NSP Ab Test Kit |
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RB28-02 | Bionote | 1 box | 108.52 EUR |
Ag Rapid CIRD-3 Ag Test Kit |
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RG11-09 | Bionote | 1 box | 123.64 EUR |
Bionote Rapid AIV Ag_NDV Ag Test Kit |
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RG15-09 | Bionote | 1 box | 164.52 EUR |
Furaltadone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092035-50tests | Abbexa | 50 tests | 537 EUR |
Furazolidone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092036-50tests | Abbexa | 50 tests | 537 EUR |
Aminohydantoin Hydrochloride Rapid Test Kit (Colloidal gold) |
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abx092037-50tests | Abbexa | 50 tests | 537 EUR |
Nitrofurazone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092038-50tests | Abbexa | 50 tests | 537 EUR |
Malachite Green Rapid Test Kit (Colloidal gold) |
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abx092041-10tests | Abbexa | 10 tests | 300 EUR |
Phenylethanolamine A Rapid Test Kit (Colloidal gold) |
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abx092044-50tests | Abbexa | 50 tests | 467 EUR |
Aflatoxin B1 Rapid Test Kit (Colloidal gold) |
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abx092050-50tests | Abbexa | 50 tests | 370 EUR |
Aflatoxin B1 Rapid Test Kit (Colloidal gold) |
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abx092055-50tests | Abbexa | 50 tests | 398 EUR |
Human Echovirus (ECHO) IgM Rapid Test Kit |
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abx092093-20tests | Abbexa | 20 tests | 272 EUR |
Human Toxoplasma (TOX) IgG Rapid Test Kit |
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abx092098-20tests | Abbexa | 20 tests | 217 EUR |
COVID-19 IgG/IgM Rapid Test Kit |
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UNCOV-20 | UnScience | 20T/kit | 155 EUR |
NATtrol Zika Virus Stock (Qualitative) (1 mL) |
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TEST | Zeptometrix | 1 mL | 1106.64 EUR |
TruStrip RDT Testosterone Rapid Test cards, 10/pk |
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1880-RDT-10 | Alpha Diagnostics | 1 pk | Ask for price |
Influenza Rapid Test Control Pack (3 X 1.5mL) |
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KZMC033 | Zeptometrix | 3 X 1.5mL | 97.84 EUR |
Adenovirus Rapid Test Control Pack (2 X 1.5mL) |
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KZMC035 | Zeptometrix | 2 X 1.5mL | 97.84 EUR |
Rotavirus Rapid Test Control Pack (2 X 1.5mL) |
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KZMC036 | Zeptometrix | 2 X 1.5mL | 97.84 EUR |
Anigen Rapid FIV Ab/FeLV Ag Test Kit |
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RC12-04-DD | Bionote | 10 tests/Kit | 152.2 EUR |
Human Hepatitis A Virus IgG Rapid Test Kit |
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abx092012-25tests | Abbexa | 25 tests | 425 EUR |
Pseudorabies Virus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092026-50tests | Abbexa | 50 tests | 321 EUR |
Canine Parvovirus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092032-40tests | Abbexa | 40 tests | 356 EUR |
Rabies Virus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092033-40tests | Abbexa | 40 tests | 356 EUR |
Clenbuterol-Ractopamine-Salbutamol Rapid Test Kit (Colloidal gold) |
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abx092039-40tests | Abbexa | 40 tests | 370 EUR |
Cattle and Goat Hydatid Antibody Rapid Test Kit |
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abx092072-40tests | Abbexa | 40 tests | 356 EUR |
Avian Influenza H5N1 Virus Antibody Rapid Test Kit |
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abx092075-40tests | Abbexa | 40 tests | 398 EUR |
Human Chlamydia Pneumoniae (CP) IgG Rapid Test Kit |
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abx092079-20tests | Abbexa | 20 tests | 258 EUR |
Human Chlamydia Pneumoniae (CP) IgM Rapid Test Kit |
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abx092080-20tests | Abbexa | 20 tests | 258 EUR |
Human Mycoplasma Pneumoniae (MP) IgG Rapid Test Kit |
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abx092081-20tests | Abbexa | 20 tests | 258 EUR |
Human Mycoplasma Pneumoniae (MP) IgM Rapid Test Kit |
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abx092082-20tests | Abbexa | 20 tests | 258 EUR |
Human Mycobacterium Tuberculosis (MT) IgG Rapid Test Kit |
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abx092084-20tests | Abbexa | 20 tests | 230 EUR |
Human Helicobacter Pylori (HP) IgG Rapid Test Kit |
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abx092090-20tests | Abbexa | 20 tests | 230 EUR |
Human Enterovirus 71 (EV71) IgM Rapid Test Kit |
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abx092091-20tests | Abbexa | 20 tests | 342 EUR |
Human Hantavirus (HV) IgM / IgG Rapid Test Kit |
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abx092094-20tests | Abbexa | 20 tests | 272 EUR |
Human Rubella Virus (RV) IgG Rapid Test Kit |
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abx092097-20tests | Abbexa | 20 tests | 217 EUR |
Human Rabies Virus (HRV) IgG Rapid Test Kit |
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abx092100-20tests | Abbexa | 20 tests | 342 EUR |
Human Treponema Pallidum (TP) Antibody Rapid Test Kit |
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abx092101-20tests | Abbexa | 20 tests | 258 EUR |
Anticyclic citrullinated peptide antibody rapid test (Colloidal Gold) |
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abx095260-80Units | Abbexa | 80 Units | 1316 EUR |
Cardiac Troponin I (cTnI) rapid test (Colloidal Gold) |
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abx095265-80Units | Abbexa | 80 Units | 1316 EUR |
Panbio™ COVID-19 IgG/IgM Rapid Test |
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ICO-T402 | Abbott | 25 Tests/Kit | 220 EUR |
Panbio™ COVID-19 Ag Rapid Test Device |
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41FK10 | Abbott | 25 Tests/Kit | 96 EUR |
CA125 (Cancer antigen) ELISA test |
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11 | Biobase | 96T/Box | Ask for price |
At the Oakland, CA and San Francisco, CA study sites, swab samples collected for RT-PCR were transferred to DNA/RNA Shield (Zymo Research, Irvine, CA), stored at room temperature, and shipped overnight at ambient temperature to Curative, Inc. (San Dimas, CA) per the manufacturer’s protocol for laboratory testing. The Curative SARS-CoV-2 Assay, an FDA Emergency Use Approved (EUA) test, was used as the RT-PCR reference method [10].