One Step Leptospira IgG/IgM Rapid Diagnostic test ,detection of Leptospria Antibody, gold colloidal method

Intended Use:

The Leptospira IgG/IgM Rapid Test Cassette (Whole Blood/Serum/Plasma) is a rapid chromatographic immunoassay for the qualitative detection of IgG and IgM antibodies to Leptospira interrogans in human’s whole blood, serum or plasma.

Summary:

Leptospirosis occurs worldwide and is a common mild to severe health problem for humans and animals, particularly in area with a hot and humid climate. The natural reservoirs for leptospirosis are rodents as well as a large variety of domesticated mammals. Human infection is caused by Leptospira interrogans, the pathogenic member of the genus of Leprospira1,2. The infection is spread via urine from the host animal.

After infection, leptospires are present in the blood until they are cleared after 4 to 7 days following the production of anti-Leptospira interrogans antibodies, initially of the IgM class. Culture of the blood, urine and cerebrospinal fluid is an effective means of confirming the diagnosis during 1st to 2nd weeks after exposure. Serological detection of anti- Leptospira interrogans antibodies is also a common diagnostic method. Tests are available under this category:1) The microscopic agglutination test (MAT) ; 2) ELISA; 3) Indirect fluorescent antibody tests (IFATs)6. However, all above mentioned methods require a sophisticated facility and well- trained technicians.

TEST PRINCIPLE

The Leptospira IgG/IgM Rapid Test Cassette (Whole Blood/Serum/Plasma) is a qualitative, membrane based immunoassay for the detection of IgG and IgM antibodies to Leptospira in whole blood, serum or plasma. The membrane is pre-coated with recombinant HCV antigen on the test line region of the cassette. During testing, the whole blood, serum or plasma specimen reacts with recombinant Leptospira interrogans antigen conjugated colloid gold. The mixture migrates upward on the membrane chromatographically by capillary action to react with mouse anti-human IgG or/and mouse anti-human IgM on the membrane and generate a colored line. Presence of this colored line indicates a positive result, while its absence indicates a negative result. To serve as a procedural control, a colored line will always appear at the control line region indicating that proper volume of specimen has been added and membrane wicking has occurred.

TEST PROCEDURE

1. Bring the pouched test device to room temperature(15-30℃) prior to testing. Do not open pouch until ready to perform the assay.

2. Remove the test cassette from the sealed pouch and use it within one hour. Best results will be obtained if the assay is performed as soon as possible.

3. Place the test cassette on a clean and level surface. Hold the dropper vertically; draw the specimen about 1cm above the upper end of the nozzle as shown in illustration below. Transfer 1 full drop (approx. 20μL) of specimen to each sample well, then add 2 drops of buffer (approximately 80μL) to each sample well and start the timer. See the illustration below.

4. Wait for the colored line(s) to appear. The result should be read at 15 minutes. Do not interpret results after 20 minutes.

INTERPRETATION OF RESULTS

Positive:

Two red lines are visible in the result window. The intensity of the test line may be

weaker or darker than that of the control line. This still means a positive result.

Negative:

The control line appears in the result window, but the test line is not visible.

Invalid:

If the control line does not appear in the result window, the test results are INVALID regardless of the presence or absence of the line in the test region.

PERFORMANCE CHARACTERS:

Sensitivity and Specificity

A total of 230 samples from susceptible subjects were tested by the Leptospira IgG/IgM Rapid Test Cassette and by a commercial Leptospira IgM EIA kit. Comparison for all subjects is shown in the following table.

IgM Results

Relative Sensitivity: 90.0% (95%CI*: 55.5%-99.7%)

Relative Specificity: 98.6% (95%CI*: 96.1%-99.7%)

Accuracy: 97.4% (95%CI*: 94.7%-98.9%) *Confidence Intervals

A total of 239 samples from susceptible subjects were tested by the Leptospira IgG/IgM Rapid Test Cassette and by a commercial Leptospira IgG EIA kit. Comparison for all subjects is shown in the following table.

IgG Results

Relative Sensitivity: 93.8% (95%CI*: 69.8%-99.8%)

Relative Specificity: 98.7% (95%CI*: 96.1%-99.7%)

Accuracy: 98.3% (95%CI*: 95.8%-99.5%)

NOTE: Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for the control line failure. Review the procedure and repeat the test with a new device. If problem persists, please contact your local distributor.