Nov 20, 2020
Version 2
SensingSelf S1 Rapid Antigen Test (Saliva/Sputum/Stool) V.2
- Shripal C Gandhi1,
- Santo Purnama2,
- Keyur Patel2,
- Praveen Sukumara2,
- Dr Rinu R Ravi2
- 1Sensing Self Pte Ltd, Singapore;
- 2Sensingself pte. ltd.
- Coronavirus Method Development Community
- SensingSelfMission
External link: http://www.sensingself.me
Protocol Citation: Shripal C Gandhi, Santo Purnama, Keyur Patel, Praveen Sukumara, Dr Rinu R Ravi 2020. SensingSelf S1 Rapid Antigen Test (Saliva/Sputum/Stool). protocols.io https://dx.doi.org/10.17504/protocols.io.bpudmns6Version created by Shripal C Gandhi
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: November 18, 2020
Last Modified: November 20, 2020
Protocol Integer ID: 44645
Keywords: Covid-19 Rapid Antigen Test, SARS-CoV-2 diagnosis, Sputum and Stool based detection , novel coronavirus, S protein, ACE2 receptor, SARS.CoV, chromatography test kit, novel coronavirus detection, detection of SARS-CoV-2, S1 COVID-19 Rapid Antigen test kit, COVID-19 diagnosis, COVID-19 cases,
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Abstract
Summary:
The S1 COVID-19 Rapid Antigen test kit developed by Sensing Self Pte. Ltd. can quickly and qualitatively detect the spike glycoprotein of novel coronavirus (SARS-COV-2) in human saliva/sputum/stool samples. It can be used as an aid for COVID-19 diagnosis.
Objective:
According to the clinical trial plan, the S1 COVID-19 Rapid Antigen test kit or “test reagent”, is to test saliva/sputum/stool samples from healthy subjects and confirmed COVID-19 patients. Test results are compared with another commercial SARS-COV-2 nucleic acid detection kit with CFDA approval, which is defined as the “gold standard”. The sensitivity, specificity, and total agreement rate are used to evaluate the feasibility of the test reagent in clinical applications.
Method:
A collection of clinical samples were examined by the S1 COVID-19 Rapid Antigen test kit and the gold standard SARS-COV-2 nucleic acid detection kit in parallel, to calculate the clinical sensitivity, clinical specificity and total agreement rate of the test reagent.
Results:
Compared to the gold standard, the clinical sensitivity of test reagent reached 90.0%, the clinical specificity reached 100.0%, and the total coincidence rate reached 95.0%.
Conclusions:
The performance of test reagent has a high agreement rate with the gold standard, proving its good feasibility in diagnosing suspected COVID-19 cases.
Some of the sample collection steps were adapted from the published protocol:
Guidelines
This product is suitable for the qualitative detection of novel coronavirus in Saliva/Sputum/Stool samples. It provides an aid in the diagnosis of infection with novel coronavirus.
Materials
Materials needed for sample collection:
- Disposable paper cup
Materials needed for sample preparation:
- Disposable sample extraction tube
- Cotton swab
Materials needed for performing the test procedure:
- Disposable test card
Chemical Characterization: Substances List of ingredients:
- PVC sheet
| Component | CAS # | % W/V | |
| PVC | 9002-86-2 | ≤100% | |
| Acrylic (Acrylate) | 7910-7 | <1% |
2. Nitrocellulose membrane coated with a control line and a test line
| Component | CAS # | % W/V | |
| Nitrocellulose | 9004-70-0 | ≤100% | |
| Antibody | N/A | <3% | |
| Disodium hydrogen phosphate | 10039-32-4 | <0.5% | |
| Sodium dihydrogen phosphate | 13472-35-0 | <0.1% | |
| NaCl | 7647-14-5 | <1% | |
| Water | 7732-18-5 | > 95% |
3. Absorbent Paper
| Component | CAS # | % W/V | |
| Cellulose microcrystalline | 113669-95-7 | ≤100% |
4. Fibreglass membrane
| Component | CAS # | % W/V | |
| Fiberglass | 65997-17-3 | ≤100% |
5. Desiccant
| Component | CAS # | % W/V | |
| Silica gel | 112945-52-5 | ≤100% |
6. Foil pouch and label
| Component | CAS # | |
| Poly(Ethylene Terephthalate) | 25038-59-9 | |
| Aluminium | 7429-90-5 | |
| Polypropylene | N/A |
7. Reagent Solution / Buffer:
| Component | CAS # | Concentration | |
| NaCl | 7647-14-5 | 136mM | |
| Na2HPO4 | 7758-79-4 | 8mM | |
| KH2PO4 | 7778-77-0 | 2mM | |
| KCl | 7447-40-7 | 2.6mM | |
| Water | 7732-18-5 | > 95% |
The test unit does not contain any human source material.
Safety warnings
1. S1 COVID-19 Rapid Antigen test kit is only applicable to stool and sputum samples. Blood, serum, plasma, urine and other samples may cause abnormal results. Due to the large sampling difference of oropharyngeal swabs, abnormal results may also appear in the test using the oropharyngeal swabs. We recommend using stool samples first.
2. If the sputum sample is negative, it is recommended to use stool examination again, because the sputum sample varies greatly among individuals and there are many factors affecting the examination. If any sample tests positive, please go to the hospital for further clinical diagnosis.
3. Please make sure that a proper amount of sample is added for testing. Too much or too little sample may cause deviations in results.
4. For positive judgement, it can be confirmed as soon as both T and C-line appeared. That may be in 3-15 minutes after the sample added. For negative judgement, please wait for 15 minutes after the sample added, C-line appears while no T line appeared. The result is invalid after 20 minutes after the sample added.
5. If part of the test paper in the strip is out of the test window, or more than 2 mm of filter paper or latex pad is exposed in the test window, do not use. Otherwise, the test result is invalid and should replace with another new kit.
6. The test card is a disposable product. Please dispose of properly after use.
7. This test device is disposable, please use within the validity period. After use, the test reagent, sample and other waste should be treated in accordance with the relevant national regulations.
Before start
1. Store as packaged in the hermetic bag at the specified temperature (2 °C -30 °C or 38 °F - 85 °F ) and avoid direct sunshine. The kit is stable within the expiration date printed on the labelling.
2. Once the hermetic bag is opened, the test should be used within one hour. Prolonged exposure to a hot and humid environment will cause product deterioration.
3. Check the lot number and expiration date printed on the labelling.
While collecting sputum is significantly easier than swabs, sputum samples can be difficult to work with. It is important to follow the sample collection guidelines to ensure that sputum, not saliva, is being collected.
SALIVA SAMPLE COLLECTION
SALIVA SAMPLE COLLECTION
Saliva should be collected with the assistance of a healthcare worker or technician.
Before collection, clean hands using alcohol-based sanitizer or soap and water (no fragrances) and wear appropriate PPE (at minimum, gloves and a mask).
While preparing collection materials, direct the sample provider to begin pooling saliva in their mouth. Saliva production can be stimulated by thinking about food (favorite foods, upcoming meals, etc.) or about the saliva collection itself.
Note
This protocol is intended for the collection of the normal saliva that naturally pools into the mouth. No coughing or sniffing prior to sample collection is required.
Ideally, water should be avoided 10 minutes prior to collection. Other drinks, food, and nasal sprays should be avoided for half an hour before sample collection.
Once you have pooled saliva in your mouth, gently expel saliva into the disposable paper cup.
SPUTUM SAMPLE COLLECTION
SPUTUM SAMPLE COLLECTION
Educate the patient about the difference between sputum and oral secretions (saliva).
Rinse the mouth with clean water. This is important to make sure there won’t be mouth bacteria in the sputum collected.
Put one hand over the mouth with a tissue and put the other hand on your stomach.
Cough deeply, so that you can really feel it in your stomach. Do not take shallow coughs from the throat or chest.
Note
If you are having trouble-
1. Get a pat- ask somebody to pat you solidly up and down your back to help you release the sputum.
2. Stretch and try again- sometimes it helps to relax a bit. When you are ready, rinse and spit and try again.
Once the sputum (phlegm) is in your mouth, release it into the disposable paper cup.
STOOL SAMPLE COLLECTION
STOOL SAMPLE COLLECTION
Use disposable gloves while handling a stool sample. Stools can contain material that spreads infection.
Do not collect the stool from the toilet. The stool must not have any contact with urine.
Note
1. To ensure the stool does not come in contact with urine, pass urine before collecting the stool specimen.
2. To ensure that the stool does not come in contact with the toilet bowl or water, loosely drape a long section of plastic wrap over the rim on both sides of the toilet bowl creating a “pocket” in the centre.
With the help of a disposable sample extraction tube collect the required quantity of stool sample for further steps.
TEST PROCEDURE
TEST PROCEDURE
Allow the test device and specimens to equilibrate to temperature (15 °C -30 °C or 59 °F -86 °F ) prior to testing.
Stool Sample: Unscrew the sampling bottle, use the sampling rod to pick up 10 mg to 50 mg of fresh stool samples (equivalent to the size of a match head)；or swab the stool with a cotton swab.
Sputum Sample: Unscrew the sampling bottle, use the sampling rod or a cotton swab to pick up 10 mg to 50 mg of fresh sputum samples.
Put the sample collected into the tube and shake and mix completely.
Take the test card from the packaging bag, place it on a table, cut off the protrusion of the collection tube, and add 3 Drops of the sample into the sample hole vertically.
Wait for the appearance of the red stripe on T line, read the result in 00:15:00 minutes, and judge it invalid after 00:20:00 minutes.
Take the test card from the packaging bag, place it on a table, cut off the protrusion of the collection tube, and add 150 µL (approximately 3 drops) of the sample into the sample hole vertically.
INTERPRETATION OF RESULTS
INTERPRETATION OF RESULTS
Positive (+): Both of T and C lines appear in 00:03:00 to 00:15:00 minutes.
Negative (-): C-line appears while no T line appears in 00:15:00 minutes after the sample added.
Invalid: As long as the C-line does not appear, it indicates that the test result is invalid, and should retest with another test card.