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Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test


The Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test is a lateral flow immunoassay intended for the qualitative detection of neutralizing antibodies to SARS-CoV-2 in serum, plasma and whole blood. The Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. The Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test should not be used to diagnose acute SARS-CoV-2 infection.

For prescription use only. For in vitro diagnostic use only. For emergency use authorization use only.

Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases such as Severe Acute Respiratory Syndrome (SARS-CoV). SARS-CoV-2 is a new strain that has not been previously identified in humans. Coronaviruses are zoonotic, meaning they are transmitted between animals and people. Several known coronaviruses are circulating in animals that have not yet infected humans.

SARS-CoV-2 is a new coronavirus, causes an infectious disease named COVID-19 (Coronavirus disease 2019). Patients with SARS-CoV-2 report a mild to severe respiratory illness with symptoms of: fever, cough, shortness of breath. There is an urgent need for rapid tests to manage the ongoing pandemic.

SARS-CoV-2 has several structural proteins including spike (S), envelope (E), membrane (M) and nucleocapsid (N). The spike protein (S) contains a receptor-binding domain (RBD), which is responsible for recognizing the cell surface receptor, angiotensin converting enzyme-2 (ACE2). It is found that the RBD of the SARS-CoV-2 S protein strongly interacts with the human ACE2 receptor leading to endocytosis into the host cells of the deep lung and viral replication.

Infection with SARS-CoV-2 initiates an immune response, which includes the production of antibodies in the blood. Not all antibodies can block cellular infiltration and replication of the SARS-CoV-2 virus. The subpopulation of the antibodies that can block cellular infiltration and replication of the virus are named neutralizing antibodies. It is unknown how long it takes for neutralizing antibodies to be produced, and if they are always produced after SARS-CoV-2 infection. While individuals infected with SARS- CoV-2 develop antibodies to the virus, not all of them develop neutralizing antibodies to SARS-CoV-2.

The Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test is intended for qualitative detection of neutralizing antibodies indicative of SARS-CoV-2 infection and is to be used as a predictor of immunity condition of COVID-19.


The Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test is a blocking rapid detection tool, which mimics the virus-host interaction by a direct protein-protein interaction between RBD and host cell receptor ACE2. The highly specific interaction can be blocked by neutralizing antibodies against SARS-CoV-2 RBD, the same manner as in a conventional Virus Neutralization Test (VNT).

This lateral flow assay contains two key components: the recombinant SARS-CoV-2 RBD fragment and rabbit IgG, labeled by colloidal gold are as tracers; and the human ACE2 receptor protein (hACE2) and goat anti-rabbit IgG antibody, coated with cellulose nitrate membrane. The protein-protein interaction between RBD and hACE2 can be blocked if the test samples contain a certain level of neutralizing antibody against SARS-CoV-2.


When specimens are processed and added to the test device, neutralizing antibodies present in the specimen will bind to the RBD labeled colloidal gold and block the protein-protein interaction between RBD and ACE2. The unbound RBD labeled colloidal gold as well as any RBD labeled colloidal gold bound to non-neutralizing antibody will be captured on the test line. The colloidal gold labeled rabbit IgG antibody is bound to the goat anti- rabbit IgG antibody coated with a colored band (C line), which acts as a procedural quality control line. If the C Line does not develop, the assay is invalid regardless of color development of the T Line. Repeat the assay with a new device. 


Material Provided:

There are two kit sizes. The kit component configurations are provided below: 




Kit Size (#of Tests)



Test Cassette (#)



Sample Diluent (# of Bottles)



Transfer pipette



IFU Leaflet



Material Required But Not Provided:



1.Store the detector buffer at 2-30˚C.

2.Store the Healfo SARS-CoV-2 Neutralizing Antibody Rapid Test at 2-30˚C; It can be stable until the expiration date.

3.If stored at 2-8˚C, ensure that the test device is brought to 15-30˚C before opening.

4.Do not freeze the kit or store the kit over 30˚C.



Consider any materials of human origin as infectious and handle using standard biosafety procedures.


Serum or Plasma or Whole Blood

No special preparation or fasting of the patient is necessary. Serum or plasma derived from citrate or EDTA (ethylenediaminetetraacetate) as anticoagulants may be used.

Drops of whole blood can be obtained by venipuncture. Do not use hemolyzed blood for testing. Currently, no experimental data exists to support the use finger stick specimens.


Serum or plasma specimens should be tested as soon as possible after collection. If specimens are not tested immediately, store at 2-8°C for up to 7 days. For long-term storage, specimens should be frozen at –20°C or colder. Specimens repeatedly frozen and thawed more than five (5) times or those containing particulate matter may give erroneous results.

Whole blood specimens should be stored at 2-8˚C if not tested immediately. The specimens must be tested within 24 hours after collection.


Step 1: For fresh samples, begin with Step 2. For frozen samples, bring the specimens and test components to room temperature, and mix the specimen well once thawed.

Step 2: When ready to test, open the pouch at the notch and remove the test device. Place the test device on a clean, flat surface.

Step 3: Label the device with specimen ID number.

Step 4: Using a transfer pipette, transfer serum, plasma or whole blood, careful not to exceed the specimen well. The volume of the specimen is around 10μL. For better precision, transfer specimen by a pipette capable of delivering 10μL of volume.

Holding the transfer pipette vertically, dispense 10µL of the specimen into the center of the sample well (S well) making sure that there are no air bubbles.

Then, add 2 drops of Sample Buffer immediately into the sample well (S well).

Step 5: Set up a timer.


Step 6: Read the results in 15-20 minutes.

Don’t read results after 20 minutes. To avoid confusion, discard the test device after interpreting the result. 


1.Valid Assay


1.1 Positive:A tinted colored band or obvious color band on the test line, colored band on control line: medium neutralizing antibody level or high neutralizing antibody level.

1.2 Negative :1.1  There is no colored band on test line, colored line band on control line: no neutralizing antibody or very low neutralizing antibody level.

2. Invalid Assay:

If the C Line does not develop, the assay is invalid regardless of color development of the T Line as indicated below. Repeat the assay with a new device.



Clinical Performance:

1.Clinical Performance

The SARS-CoV-2 Neutralization Antibody Rapid Test has been evaluated with serum specimens obtained from patients. A commercialized ELISA assay was used as the reference method. The results show that The SARS-CoV-2 Neutralization Antibody Rapid Test has a high overall accuracy.


Reference method


SARS-CoV-2 Neutralization Antibody Rapid Test












Total Results




Relative Sensitivity: 95.33%

Relative Specificity: 98.44%

Accuracy: 97.32%

Assay Cross Reactivity:

A low titer sample was diluted 1:100 to a serum or plasma sample containing antibodies reactive to one of following pathogens were tested along with unspiked samples in duplicate. No false positivity or false negativity was found: Human coronavirus(collected before Oct 2019)、HBV、HCV、HIV-1、HIV-2、Adenovirus、Human Metapneumovirus (hMPV)、Parainfluenza virus 1-4、Influenza A、Influenza B、Enterovirus 71、Respiratory syncytial virus、Rhinovirus、Chlamydia pneumoniae、Streptococcus pneumoniae、 Mycobacterium tuberculosis、Mycoplasma pneumoniae、EB Virus.

Potentially Interference Substances:

A low titer positive serum sample or negative serum sample was spiked with one of the following substances to specified concentrations and tested in duplicate. No false positivity or false negativity was found: Hemoglobin 10 mg/mL、Bilirubin Conjugated 0.4 mg/mL、Bilirubin Unconjugated 0.4 mg/mL、 Triglycerides 15 mg/mL、Cholesterol 4 mg/mL、Human Anti-mouse Antibody 800 ng/mL、 Rheumatoid Factor 2000 IU/mL、Human Serum Albumin 60 mg/mL、Histamine hydrochloride 4 mg/L 、α-IFN 200 mg/L、Zanamivir 1 mg/L、Oseltamivir carboxylate 1 mg/L、Abidol 40 mg/L、 Levofloxacin 200 mg/L、Ceftriaxone 400 mg/L、Meropenem 200 mg/L、Tobramycin 10 mg/L、 Ribavirin 40 mg/L、Human IgG 8 mg/mL、Human IgM 0.4 mg/mL.



1.Internal Control: This test contains a built-in control to satisfies the quality control requirements. The C Line develops after addition of the specimen and sample diluent. If the C Line does not develop, the test is invalid, indicating that the test should be repeated.

2.Positive and Negative Control: Positive and negative controls should be tested to ensure the proper performance of the assay, particularly under the following circumstances: 1) new kits (new lot or new shipment); 2) new user; 3) new test environment (e.g., natural light vs. artificial light).; 4) abnormal storge environment (outside of 2-30°C); 5) abnormal working environment (outside of 15-30°C); 6) To investigate the cause of repeated invalid results.



Inadequate adherence to package insert instructions may result in erroneous results.

1.Caution: Handle all relative biological materials as though capable of transmitting infectious agents.

2.Specimens should not be transported under extreme adverse temperature conditions.

3.Kits should not be used past their expiration dates.

4.All clinical specimens and materials used to collect these specimens should be considered potentially infectious and handled accordingly.

5.The assay should be performed at 15˚C to 30˚C.

6.Do not smoke, eat, or drink in areas where specimens or kit regents are handled.

7.Use disposable gloves and handle all materials used in the test (including samples, and controls) cautiously as though capable of transmitting infectious agents.

8.Dispose of all materials that have come into contact with specimens and reagents in accordance with local, state, and federal regulations.



1.Serum or plasma derived from sodium citrate, sodium heparin, or EDTA (ethylenediaminetetraacetate) as anticoagulants or whole blood may be used with this assay. Using other types of samples may not yield accurate results.

2.A test result that is INVALID should not be reported and the sample(s) should be retested.

3.The SARS-CoV-2 Neutralization Antibody Rapid Test is a qualitative assay, and the intensity of the test line does not necessarily correlate to SARS-CoV-2 antibody titer in the specimen.

4.A negative or non-reactive result can occur if the quantity of antibodies for the SARS-CoV-2 virus present in the specimen is below the detection limit of the assay, or the virus has undergone minor amino acid mutation(s) in the epitope recognized by the antibody utilized in the test.

5.If symptoms persist and the result from the SARS-CoV-2 Neutralization Antibody Rapid Test is negative or non-reactive, it is recommended to re-sample the patient a few days later or test with an alternative test device.

6.The results obtained with this test should only be interpreted in conjunction with clinical findings, and the results from other laboratory tests and evaluations.

7.This test should not be used for screening of donated blood

8.Negative results do not rule out SARS-CoV-2 infection, particularly in those who have been in contact with the virus. Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals.

9.Results from antibody testing should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection or to inform infection status. 



       Consult instructions for use                   Use by


       For in vitro diagnostic use only                Catalog #

LOT批号温度极限标识 - 2到30度

       Store between 2-30°C                       Lot Number


        Do not reuse                             Tests per kit


        Authorized Representative


       Date of manufacture                        Manufacturer



生产厂家Healvet Medtech GZ Ltd.

Add: B201, Building 2, No.6 Xinrui Road, Hi-Tech Industrial Development Zone, Guangzhou, P.R.China

Tel: +86-020-61855600 / +86-13828472609

Email: Healvet@healfo.com

欧盟代理CMC Medical Devices & Drugs S.L.

C/ Horacio Lengo N18, CP29006, Málaga-Spain


DOC Version No.: HF0016C-20210309EN