INTENDED USE
The Leptospira IgG/IgM Rapid Test is a rapid chromatographic immunoassay for the qualitative detection of IgG and IgM antibodies to Leptospira donovani in human whole blood, serum or plasma specimen.
MATERIALS
Materials Provided
- Individually packed test devices
- Disposable pipettes
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Materials Required but Not provided
- Specimen collection container
- Centrifuge
- Micropipette
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TEST PROCEDURE
Allow the test device, specimen, buffer, and/or controls to reach 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 level surface.
For Serum or Plasma Specimens:
Hold the dropper vertically, draw the specimen up to the Fill Line (approximately 10 uL), and transfer the specimen to the specimen well (S) of the test device, then add 2 drops of buffer (approximately 80 mL) and start the timer. See illustration below.
For Whole Blood (Venipuncture/Fingerstick) Specimens:
To use a dropper: Hold the dropper vertically, draw the specimen 0.5-1 cm above the Fill Line, and transfer 2 drops of whole blood (approximately 20 µL) to the specimen well (S) of the test device, then add 2 drops of buffer (approximately 80 uL) and start the timer. See illustration below.
To use a micropipette: Pipette and dispense 20 µL of whole blood to the specimen well (S) of the test device, then add 2 drops of buffer (approximately 80 µL) and start the timer.
3. Wait for the colored line(s) to appear. Read results at 10 minutes. Do not interpret the result after 20 minutes.
INTERPRETATION OF RESULTS
IgG POSITIVE: The colored line in the control line region (C) appears, and a colored line appears in test line region G The result is positive for Leptospira specific-IgG and is probably indicative of secondary Leptospira infection.
IgM POSITIVE: The colored line in the control line region (C) appears, and a colored line appears in test line region M. The result is positive for Leptospira specific-IgM antibodies and is indicative of primary Leptospira infection.
IgG AND IgM POSITIVE: The colored line in the control line region (C) appears, and two colored lines should appear in test line regions G and M. The color intensities of the lines do not have to match. The result is positive for IgG & IgM antibodies and is indicative of secondary Leptospira infection.
NEGATIVE: Only one colored band appears in the control region (C). No line appears in test line regions G or M.
INVALID:NoControlline(C)appears.
PERFORMANCE CHARACTERISTICS
Clinical Sensitivity, Specificity and Accuracy
The Leptospira IgG/IgM Rapid Test has been evaluated with specimens obtained from a population of symptomatic and asymptomatic individuals. Results were confirmed by a leading commercial Leptospira PCR kit.
Leptospira IgG/IgM Rapid Test vs. PCR kit
| Leptospira Infection |
Result |
IgM |
IgG |
| Primary Infection |
Positive |
20 |
1 |
| Negative |
0 |
19 |
| Total |
20 |
20 |
| Relative Sensitivity |
>99.0% |
5.0% |
| Secondary Infection |
Positive |
18 |
30 |
| Negative |
12 |
0 |
| Total |
30 |
30 |
| Relative Sensitivity |
60.0% |
>99.0% |
| Non-Leptospira Infection |
Positive |
0 |
0 |
| Negative |
170 |
170 |
| Total |
170 |
170 |
| Relative Specificity |
>99.0% |
>99.0% |
For the primary and secondary infection, the overall sensitivity is IgM 76.0%, IgG 62.0%, the overall specificity is IgM >99.0%, IgG IgM >99.0% and the overall accuracy is IgM 94.5%, IgG 91.4%.
Precision
Intra-Assay
Within-run precision has been determined by using 10 replicates of four specimens: a negative, an IgG positive, an IgM positive and an IgG/IgM dual positive. The specimens were correctly identified >99% of the time.
Inter-Assay
Between-run precision has been determined by 10 independent assays on the same four specimens: a negative, an IgG positive, an IgM positive and an IgG/IgM dual positive. Three different lots of the Leptospira IgG/IgM Rapid Test have been tested using these specimens. The specimens were correctly identified >99% of the time.
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