Vaccine titer test: COVID-19 Neutralizing Antibody kit

SPECIMEN COLLECTION AND PREPARATION

The SARS-CoV-2 Neutralizing Antibody Rapid Test (COVID-19 Ab) (Whole Blood/Serum/Plasma) can be performed using whole blood. Both Fingerstick Whole Blood and Venipuncture Whole Blood can be used.

To collect Fingerstick Whole Blood specimens:

• Wash the patient’s hand with soap and warm water or clean with an alcohol swab. Allow to dry.
• Massage the hand without touching the puncture site by rubbing down the hand towards the fingertip of the middle or ring finger.
• Puncture the skin with a sterile lancet. Wipe away the first sign of blood.
• Gently rub the hand from wrist to palm to finger to form a rounded drop of blood over the puncture site.
• Add the specimen to the test device by using a micropipette measuring 10-100uL range.

Separate serum or plasma from blood as soon as possible to avoid hemolysis. Use only clear, non-hemolyzed specimens.

Testing should be performed immediately after specimen collection. Do not leave the specimens at room temperature for prolonged periods. Whole blood collected by venipuncture should be stored at 2-8°C if the test is to be run within 2 days of collection. For long term storage, specimens should be kept below -20°C.Whole blood collected by Fingerstick should be tested immediately.

Bring specimens to room temperature prior to testing. Frozen specimens must be completely thawed and mixed well prior to testing. Specimens should not be frozen and thawed repeatedly for more than three times.

If specimens are to be shipped, they should be packed in compliance with local regulations covering the transportation of etiologic agents.

COMPONENTS

For serum or plasma (quantitative)

Materials Provided

1) Foil pouches, with test cassettes

2) Calibrator card

3) Instruction for use

Materials Required But Not Provided

1) Micropipette and tips

2) Timer

For fingerpick whole blood (semi-quantitative or qualitative)

Materials Provided

1) Foil pouches, with test cassettes

2) Calibrator card

3) Assay buffer

4) Lancet

5) Iodine swab

6) Instruction for use

Materials Required But Not Provided

1) Mocropipette and tips (for semi-quantitative only)

2) Timer

TEST PROCEDURE

Allow the test device, specimen, buffer, and/or controls to equilibrate to room temperature (15-30°C) prior to testing.

1. Bring the pouch to room temperature before opening. Remove the test device from the sealed pouch and use it as soon as possible.
2. Place the test device on a clean and horizontal surface.

A.For Serum or Plasma Specimens (quantitative):

Use a pipette to collect the serum or plasma. Use the pipette to transfer approximately 100 mL of the specimen into the specimen well (S) of the test device. Start the timer.

B.For Fingerpick Whole Blood Specimens (quantitative, dilution factor is 4):

To use a micropipette: Hold the pipette vertically onto the puncture site, and place approximately 50 µL of whole blood into the specimen well (S) of the test device, then add exactly 50 uL of buffer into the specimen well and start the timer. See illustration below.

C.For Fingerpick Whole Blood Specimens (qualitative):

To use a capillary dropper: Hold the dropper vertically onto the puncture site, and transfer 5 drops of whole blood (approximately 50 µL) into the specimen well (S) of the test device, then add 1 drop of buffer (approximately 40-50 uL) and start the timer. See illustration below.

3.Wait for the colored line(s) to appear. Read results at 10 minutes. Do not interpret the result after 15 minutes.

RAPID TEST READER

1. Press and hold the white start button for 2 ~ 3 seconds to start the machine

2. Swipe the calibrator card onto the card reading area, to introduce the calibration curve into the reader.

3. Insert the test card into the detection cavity of the reader on the right side. Make sure the window of card in while sample well out.  

4. Read the results on the display of the reader. 

INTERPRETATION OF RESULTS

- Positive (+): Only C line appears, or T line is equal to C line or weaker than C line. It indicates that there are SARS-CoV-2 neutralizing antibodies in the specimen.

- Negative (-): Both the T line and C line appear, when the intensity of T line is stronger than C line. It indicates that there is no SARS-CoV-2 neutralizing antibodies in the specimen, or else the titer of SARS-CoV-2 neutralizing antibodies are of very low level.

- Invalid: Control line fails to appear. Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for control line failure. Review the procedure and repeat the test with a new test. If the problem persists, discontinue using the test kit immediately and contact your local distributor.

Expected Results For Vaccination Reference.

The results if carrying COVID-19 vaccination are expected to be like below.

- Before first dose: Negative by rapid test

- 3 weeks after first dose: weak or middle positive

- 1 week after second dose: middle or high positive

- 2 weeks after second dose: middle or high positive

Sense of quantitative and qualitative result.

PERFORMANCE CHARACTERISTICS

1. Relative Sensitivity, Specificity and Accuracy

The SARS-CoV-2 Neutralizing Antibody Rapid Test (COVID-19 Ab) has been evaluated with specimens obtained from a population of positive and negative specimen. Results were confirmed by a commercial SARS-CoV-2 Neutralization Antibody Detection Kit (ELISA kit, cutoff 30% signal inhibition).

Relative Sensitivity: 96.97%（95%CI：83.35%～99.99%）  

Relative Specificity: 100.00%（95%CI：97.29%～100.00%）

Accuracy: 99.50%（95%CI：96.94%～99.99%）

2.Detection of Limit

Cutoff：100ng/ml

Detection range：50~5000ng/ml

3.Calibration Curves