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.
NOVATest Antigen Rapid Kit (NOVA Test) |
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nCov-500 | Atlas Link Technology | 20 Tests | 162 EUR |
SARS-CoV-2 Antigen Rapid Test Kit |
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CoV2Ag-1 | UnScience | 1T | 9.6 EUR |
SARS-CoV-2 Antigen Rapid Test Kit |
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CoV2Ag-25 | UnScience | 25T/kit | 42 EUR |
SARS-CoV-2 Rapid Antigen Test Nasal |
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9901-NCOV-03G | Roche Diagnostics | 25 Tests/Kit | 112.8 EUR |
NOVATest Antigen Rapid Test Kit (For Single Use) (NOVA Test) |
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nCov-500-01 | Atlas Link Technology | 1T | 162 EUR |
Human Streptococcus Pneumoniae (SP) Antigen Rapid Test Kit |
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abx092096-20tests | Abbexa | 20 tests | 477.6 EUR |
Melamine Rapid Test Kit |
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abx092011-50tests | Abbexa | 50 tests | 444 EUR |
Accu-Tell COVID-19 IgG/IgM Rapid Test |
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GEN-B352-20tests | Accu test | 20 tests | 283.2 EUR |
Accu-Tell COVID-19 IgG/IgM Rapid Test |
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GEN-B352-40tests | Accu test | 40 tests | 385.2 EUR |
Avian Influenza Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092015-40tests | Abbexa | 40 tests | 518.4 EUR |
Newcastle Disease Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092016-40tests | Abbexa | 40 tests | 518.4 EUR |
Human Chlamydia Trachomatis Antigen Rapid Test Kit (Colloidal gold) |
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abx092049-20tests | Abbexa | 20 tests | 276 EUR |
Coronavirus (SARS-Cov-2) Antigen Rapid Test Device (Saliva) |
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IOV87952 | INVBIO | 20T/kit | 46.8 EUR |
Melamine (MEL) Rapid Test Kit |
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abx092057-50tests | Abbexa | 50 tests | 444 EUR |
Clenbuterol (CLE) Rapid Test Kit |
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abx092058-50tests | Abbexa | 50 tests | 292.8 EUR |
Ractopamine (RAC) Rapid Test Kit |
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abx092059-50tests | Abbexa | 50 tests | 292.8 EUR |
Salbutamol (SAL) Rapid Test Kit |
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abx092060-50tests | Abbexa | 50 tests | 292.8 EUR |
Tetracycline (TCs) Rapid Test Kit |
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abx092063-50tests | Abbexa | 50 tests | 477.6 EUR |
Sulfonamides (Sas) Rapid Test Kit |
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abx092064-40tests | Abbexa | 40 tests | 477.6 EUR |
Quinolones (QNs) Rapid Test Kit |
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abx092065-40tests | Abbexa | 40 tests | 477.6 EUR |
Ciprofloxacin (CPFX) Rapid Test Kit |
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abx092066-50tests | Abbexa | 50 tests | 477.6 EUR |
Quinolones (QNs) Rapid Test Kit |
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abx092067-40tests | Abbexa | 40 tests | 477.6 EUR |
Brucella Antibody Rapid Test Kit |
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abx092069-40tests | Abbexa | 40 tests | 427.2 EUR |
Procalcitonin rapid test (Colloidal Gold) |
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abx095264-80Units | Abbexa | 80 Units | 1144.8 EUR |
Avian Influenza H5 Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092014-40tests | Abbexa | 40 tests | 585.6 EUR |
Avian Influenza H7 Virus Antigen Rapid Test Kit (Colloidal gold) |
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abx092017-40tests | Abbexa | 40 tests | 518.4 EUR |
NOVATest IgG/IgM Antibody Rapid Test Kit (NOVA Test) |
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UNCOV-40 | Atlas Link Technology | 40 Tests | 115 EUR |
2019-nCoV IgG/IgM Rapid Test Cassette (Whole Blood/Serum/Plasma) |
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GEN-402-25tests | All test | 25 tests | 292.8 EUR |
Dynamiker Monkeypox Virus Ag Rapid Test |
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DNK-2114-1 | Dynamiker Biotechnology | 20 tests | 702 EUR |
Clenbuterol Rapid Test Kit (Colloidal gold) |
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abx092040-50tests | Abbexa | 50 tests | 326.4 EUR |
Ractopamine Rapid Test Kit (Colloidal gold) |
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abx092042-50tests | Abbexa | 50 tests | 360 EUR |
Salbutamol Rapid Test Kit (Colloidal gold) |
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abx092043-50tests | Abbexa | 50 tests | 410.4 EUR |
Chloramphenicol Rapid Test Kit (Colloidal gold) |
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abx092045-50tests | Abbexa | 50 tests | 427.2 EUR |
Quinolones Rapid Test Kit (Colloidal gold) |
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abx092046-50tests | Abbexa | 50 tests | 644.4 EUR |
Sulfonamides Rapid Test Kit (Colloidal gold) |
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abx092047-50tests | Abbexa | 50 tests | 661.2 EUR |
Tetracycline Rapid Test Kit (Colloidal gold) |
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abx092048-50tests | Abbexa | 50 tests | 560.4 EUR |
Zearalenone Rapid Test Kit (Colloidal gold) |
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abx092051-50tests | Abbexa | 50 tests | 493.2 EUR |
Deoxynivalenol Rapid Test Kit (Colloidal gold) |
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abx092052-50tests | Abbexa | 50 tests | 560.4 EUR |
Deoxynivalenol Rapid Test Kit (Colloidal gold) |
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abx092053-50tests | Abbexa | 50 tests | 560.4 EUR |
Aflatoxin Rapid Test Kit (Colloidal gold) |
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abx092054-50tests | Abbexa | 50 tests | 477.6 EUR |
Zearalenone Rapid Test Kit (Colloidal gold) |
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abx092056-50tests | Abbexa | 50 tests | 510 EUR |
Goat Brucella Antibody Rapid Test Kit |
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abx092070-40tests | Abbexa | 40 tests | 427.2 EUR |
Cow Brucella Antibody Rapid Test Kit |
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abx092071-40tests | Abbexa | 40 tests | 427.2 EUR |
Pig Parvovirus Antibody Rapid Test Kit |
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abx092074-50tests | Abbexa | 50 tests | 385.2 EUR |
Fetal Fibronectin rapid test (Colloidal Gold) |
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abx095261-80Units | Abbexa | 80 Units | 1863.6 EUR |
Chlamydia Rapid Test Device (Swab/Urine) |
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173-8537306 | Abbott | 20 Tests/Kit | 300 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 | 489.6 EUR |
Furaltadone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092035-50tests | Abbexa | 50 tests | 644.4 EUR |
Furazolidone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092036-50tests | Abbexa | 50 tests | 644.4 EUR |
Aminohydantoin Hydrochloride Rapid Test Kit (Colloidal gold) |
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abx092037-50tests | Abbexa | 50 tests | 644.4 EUR |
Nitrofurazone Metabolite Rapid Test Kit (Colloidal gold) |
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abx092038-50tests | Abbexa | 50 tests | 644.4 EUR |
Malachite Green Rapid Test Kit (Colloidal gold) |
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abx092041-10tests | Abbexa | 10 tests | 360 EUR |
Phenylethanolamine A Rapid Test Kit (Colloidal gold) |
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abx092044-50tests | Abbexa | 50 tests | 560.4 EUR |
Aflatoxin B1 Rapid Test Kit (Colloidal gold) |
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abx092050-50tests | Abbexa | 50 tests | 444 EUR |
Aflatoxin B1 Rapid Test Kit (Colloidal gold) |
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abx092055-50tests | Abbexa | 50 tests | 477.6 EUR |
Human Echovirus (ECHO) IgM Rapid Test Kit |
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abx092093-20tests | Abbexa | 20 tests | 326.4 EUR |
Human Toxoplasma (TOX) IgG Rapid Test Kit |
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abx092098-20tests | Abbexa | 20 tests | 260.4 EUR |
COVID-19 IgG/IgM Rapid Test Kit |
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UNCOV-20 | UnScience | 20T/kit | 186 EUR |
Panbio™ COVID-19 Ag Rapid Test Device |
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41FK10 | Abbott | 25 Tests/Kit | 115.2 EUR |
TruStrip RDT Testosterone Rapid Test cards, 10/pk |
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1880-RDT-10 | Alpha Diagnostics | 1 pk | Ask for price |
Human Hepatitis A Virus IgG Rapid Test Kit |
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abx092012-25tests | Abbexa | 25 tests | 510 EUR |
Pseudorabies Virus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092026-50tests | Abbexa | 50 tests | 385.2 EUR |
Canine Parvovirus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092032-40tests | Abbexa | 40 tests | 427.2 EUR |
Rabies Virus Antibodies Rapid Test Kit (Colloidal gold) |
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abx092033-40tests | Abbexa | 40 tests | 427.2 EUR |
Clenbuterol-Ractopamine-Salbutamol Rapid Test Kit (Colloidal gold) |
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abx092039-40tests | Abbexa | 40 tests | 444 EUR |
Cattle and Goat Hydatid Antibody Rapid Test Kit |
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abx092072-40tests | Abbexa | 40 tests | 427.2 EUR |
Avian Influenza H5N1 Virus Antibody Rapid Test Kit |
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abx092075-40tests | Abbexa | 40 tests | 477.6 EUR |
Human Chlamydia Pneumoniae (CP) IgG Rapid Test Kit |
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abx092079-20tests | Abbexa | 20 tests | 309.6 EUR |
Human Chlamydia Pneumoniae (CP) IgM Rapid Test Kit |
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abx092080-20tests | Abbexa | 20 tests | 309.6 EUR |
Human Mycoplasma Pneumoniae (MP) IgG Rapid Test Kit |
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abx092081-20tests | Abbexa | 20 tests | 309.6 EUR |
Human Mycoplasma Pneumoniae (MP) IgM Rapid Test Kit |
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abx092082-20tests | Abbexa | 20 tests | 309.6 EUR |
Human Mycobacterium Tuberculosis (MT) IgG Rapid Test Kit |
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abx092084-20tests | Abbexa | 20 tests | 276 EUR |
Human Helicobacter Pylori (HP) IgG Rapid Test Kit |
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abx092090-20tests | Abbexa | 20 tests | 276 EUR |
Human Enterovirus 71 (EV71) IgM Rapid Test Kit |
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abx092091-20tests | Abbexa | 20 tests | 410.4 EUR |
Human Hantavirus (HV) IgM / IgG Rapid Test Kit |
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abx092094-20tests | Abbexa | 20 tests | 326.4 EUR |
Human Rubella Virus (RV) IgG Rapid Test Kit |
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abx092097-20tests | Abbexa | 20 tests | 260.4 EUR |
Human Rabies Virus (HRV) IgG Rapid Test Kit |
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abx092100-20tests | Abbexa | 20 tests | 410.4 EUR |
Human Treponema Pallidum (TP) Antibody Rapid Test Kit |
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abx092101-20tests | Abbexa | 20 tests | 309.6 EUR |
Anticyclic citrullinated peptide antibody rapid test (Colloidal Gold) |
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abx095260-80Units | Abbexa | 80 Units | 1579.2 EUR |
Cardiac Troponin I (cTnI) rapid test (Colloidal Gold) |
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abx095265-80Units | Abbexa | 80 Units | 1579.2 EUR |
Influenza Rapid Test Control Pack (3 X 1.5mL) |
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KZMC033 | Zeptometrix | 3 X 1.5mL | 117.41 EUR |
Adenovirus Rapid Test Control Pack (2 X 1.5mL) |
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KZMC035 | Zeptometrix | 2 X 1.5mL | 117.41 EUR |
Rotavirus Rapid Test Control Pack (2 X 1.5mL) |
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KZMC036 | Zeptometrix | 2 X 1.5mL | 117.41 EUR |
Panbio™ COVID-19 IgG/IgM Rapid Test |
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ICO-T402 | Abbott | 25 Tests/Kit | 264 EUR |
CA125 (Cancer antigen) ELISA test |
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11 | Biobase | 96T/Box | Ask for price |
CA50 (Cancer antigen) ELISA test |
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10 | Biobase | 96T/Box | Ask for price |
CA153 (Cancer antigen) ELISA test |
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12 | Biobase | 96T/Box | Ask for price |
CA199 (Cancer antigen) ELISA test |
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13 | Biobase | 96T/Box | Ask for price |
CEA (Cancer antigen) ELISA test |
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9 | Biobase | 96T/Box | Ask for price |
TruStrip RDT Mouse IgG Rapid Test cards, 10/pk |
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6320-RDT-10 | Alpha Diagnostics | 1 Pk | 205.2 EUR |
TruStrip RDT Mouse IgG Rapid Test cards, 25/pk |
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6320-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
TruStrip RDT Rat IgG Rapid Test cards, 10/pk |
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6420-RDT-10 | Alpha Diagnostics | 1 Pk | 205.2 EUR |
TruStrip RDT Rat IgG Rapid Test cards, 25/pk |
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6420-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
TruStrip RDT Rabbit IgG Rapid Test cards, 10/pk |
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6520-RDT-10 | Alpha Diagnostics | 1 Pk | 205.2 EUR |
TruStrip RDT Rabbit IgG Rapid Test cards, 25/pk |
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6520-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
TruStrip RDT Goat IgG Rapid Test cards, 10/pk |
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7520-RDT-10 | Alpha Diagnostics | 1 Pk | 205.2 EUR |
TruStrip RDT Goat IgG Rapid Test cards, 25/pk |
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7520-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
TruStrip RDT Chicken IgY Rapid Test cards, 10/pk |
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6020-RDT-10 | Alpha Diagnostics | 1 Pk | 205.2 EUR |
TruStrip RDT Chicken IgY Rapid Test cards, 25/pk |
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6020-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
TruStrip RDT Rabbit Albumin Rapid test cards, 25/pk |
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7000-30-RDT-25 | Alpha Diagnostics | 1 Pk | 351.6 EUR |
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].