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Mycobacterium tuberculosis (TB)
3 Minute Rapid-FloTM
Visual Screening Test for Active Tuberculosis Disease
(Contains 25 Tests)
Catalog No: AMTBSF25
For in vitro diagnostic use only
Summary
The M. tuberculosis (TB) 3 Minute Visual Screening Test detects antibodies to M. Tuberculosis. This test utilizes a blend of three proprietary antigens, each derived from a slightly different strain of Mycobacterium tuberculosis. These antigens are 100% NON-INFECTIOUS, and are very sensitive for the detection of M. tuberculosis antibodies.
M. tuberculosis is the most common bacterial infection in the world, affecting approximately 2 billion people. However, because of the unique nature of this organism, only 10-15% of those infected will ultimately develop the disease. AmTech Scientific's rapid test for TB is entirely unique because it is the first available rapid screening test for active disease. Other screening tests, such as the commonly used Mantoux or tuberculin (PPD) skin test, screen for infection. But it is only those with active disease who actually become ill and spread the infection to others. Also, unlike other tests, the AmTech TB test does not give false positive results in those who have been BCG vaccinated.
It is the patients with active disease who must be identified for treatment and to prevent the continuous spread of the disease. Effective, inexpensive treatment is available once those with active TB are identified. Unless diagnosed, active TB is an often-fatal condition, and the patient with active TB will spread the disease to an average of 10-15 others per year.
Principle
The TB antigens are immobilized on a membrane, in a cassette (Figure 1). As the patient sample flows through this membrane, any antibodies present against M. tuberculosis react with and bind to the antigens. Unbound antibodies are then removed by washing with Wash Buffer solution. Next, Signal Solution (Protein-A conjugated to colloidal gold) is applied. This solution binds to human antibodies (IgG) that have attached to the antigens on the membrane. Any excess Signal Solution is removed by applying additional Wash Buffer. Within 30 seconds of this step the result should be clearly visible on the membrane. There is a Control spot on the membrane that should always react to form a visible dot under `C' (Control). This built-in control demonstrates that the test is functioning properly. Two (2) red dots indicate a TB Reactive (Positive) specimen. Note: the Control dot is only meant to demonstrate that the test is functioning properly. It is not meant for comparison to the Test dot. Positive Test dots will usually be lighter or darker than Control dots. Even very light Test dots must be read as POSITIVE.
Materials Provided
25 test cassettes. The cassettes are packaged with desiccant in a foil pouch.
A dropper bottle containing 3 ml. of a signal solution (Protein-A conjugated to colloidal gold with preservatives and stabilizers.).
A dropper bottle containing 6 ml of Wash Buffer.
Materials Not Provided
Sample diluent.
Disposable pipettes or pipette tips for dispensing the serum or plasma.
Vinyl examination gloves for handling specimens.
Sodium hypochlorite 5% or other solution required to wipe up any spills and to disinfect liquid waste.
SAFETY PRECAUTIONS
CAUTION All human source material should be considered potentially infectious. It is recommended that all specimens be handled in accordance with Biosafety Level 2 pratices as described in the CDC NIH publication "Biosafety in Microbiological and Biomedical Laboratories" or equivalent guidelines.
1. Clean and disinfect all specimen spills using a suitable disinfectant (5% sodium hypochlorite, or 2% glutaraldehyde are recommended).
2. All human source materials used in the test should be treated as if they were infectious. Follow appropriate government regulations when discarding waste materials.
3. Use a separate pipette with each sample and dispose of it properly after use.
Procedural Hints
1. Do not mix or pool reagents having different lot numbers together. Do not use more of any reagent than instructed, as this may not allow enough for performing all 25 tests, and will not improve results.
2. All reagents and patient samples must be brought to room temperature before performing the test.
3. To store unused cassettes you must re-seal these in the foil pouch containing a desiccant bag. This will maintain the stability of the test as specified in this package insert.
Once the test is begun it should followed through to completion. Interruptions may produce unreliable results.
Storage instructions and stability
Store the kit at 2o - 30o C (36o - 85oF).
The shelf life of this kit is 18 months from the date of manufacture.
Specimen Collection and Preparation
Serum or plasma may be used in the test, and must be diluted 1:10 with PBS -T-20, distilled water, or saline.
Turbid specimens may obstruct the flow through the membrane and can be filtered using a 0.45 micron filter.
Specimens should be tested within six hours after collection. The specimen must be frozen for long term storage.
Assay Procedure (see Procedural Hints)
All reagents and patient samples must be brought to room temperature before performing the test.
Remove cassette(s) from foil pouch and re-seal the pouch.
Add 2 drops (approx. 80æl) of Wash Buffer to the opening of the cassette, then wait for 30 seconds.
Add 3 drops (120æl) of diluted (1:10) serum or plasma. Wait until all of the sample has flowed through the membrane.
3. Rinse by adding 2 drops (80æl) of Wash Buffer. Wait until it has entirely drained.
4. Next add 3 drops (120 æl) of Signal Solution to the cassette. Wait until all the Signal Solution has flowed through.
5. Add 2 drops (80 æl) of Wash Buffer.
6. Within 30 seconds the result will be visible. Two (2) red dots on the membrane indicates a positive result (Figure 3). Background pink color may be present if the membrane is not washed completely. This does not invalidate the results.
Interpretation of Results
A positive sample is indicated by two (2) red dots in the vicinity of the letter 'T' (Test) and 'C' (Figure 3). A negative sample will have only one (1) red dot in the vicinity of the letter 'C'. As with all screening tests, a definitive clinical diagnosis should not be based on the results of a single test, but only made by a physician after all clinical and laboratory findings have been evaluated.
Performance Characteristics
The presence of M. tuberculosis antibodies was determined by the Rapid-FloTM TB test in specimens from 22 patient samples, obtained from India, which were categorized Type 1-4 as below.
Type
Sample
AmTech Positive
AmTech Negative
% Correct Result
Type 1
n =10 (4M; 6F)
0
10
100%
Type 2
n = 4 (4M)
0
4
100%
Type 3
n = 5 (3M; 2F)
5
0
100%
Type 4
n = 3 (2M;1F)
3
0
100%
Type 1: PPD negative, no evidence of TB
Type 2: PPD positive, no evidence of TB
Type 3: PPD positive, active TB
Type 4: PPD positive, active TB, scarred lungs
34 individuals with known BCG vaccination but negative for TB were tested at a tuberculosis clinic in Brazil.
Type
Sample
AmTech +
AmTech -
% Correct
BCG positive
TB negative
n = 34
0
34
100%
The AmTech Scientific rapid TB test was also submitted for regulatory approval to the People's Republic of China. Based on the following results obtained by their Ministry of Health, the test was approved for sale there.
Type
Sample
AmTech Positive
AmTech Negative
% Correct
Negative Controls
n = 9
0
9
100%
Positive Controls
n = 27
27
0
100%
Sputum smear positive, active disease
n = 34
32
2
94%
Sputum smear negative, active disease
n = 43
28
15
65%*
Healthy Patients
n = 35
0
35
100%
*Note that sputum smear detected 0% of these pts. ; (3) sputum smears on 3 days, the standard in most nations, have a sensitivity ranging from 50 - 70%; .
A retrospective blind-coded study was performed at the University of Minnesota on 35 serum samples provided by Departmento de Microbiologia; Instituto de Enfermedades Respiratorias.
Type
AmTech +
AmTech -
% Correct
Active TB
N = 15
15
0
100%
Lung Disease other than TB
N = 5
1
4
80%
Healthy; positive PPD
N = 15
0
15
100%
REFERENCES
1. Benjamin, R. G., and T. M. Daniel. Am. Rev. Respir. Dis. 126:1013-1016. (1982).
2. Edwards, L. B., L. Hopwood, and C. E. Palmer. Bull. W. H. O. 33:405-412. (1965).
3. Kalish, S. B., R. C. Radin, J. P. Phair, D. Levitz, C. R. Zeiss, and E. Metzger. J. Infect. Dis. 147:523-530. (1983).
4. Middlebrook, G., Z. Reggiardo, and W. D. Tigert. Am. Rev. Respir. Dis. 115:1066-1069.
5. Runyon, E. H., A. G. Karlson, G. P. Kubica, and L. G. Wayne. Mycobacterrium. Manual of clinical microbiology, 3rd ed. American Society for Microbiology, Washington, D.C. (1980).
6. Snider, D. E., Jr., R. C. Good, J. O. Kilburn, L. F. Laskowski, R. H. Lusk, J. J. Marr, Z. Reggiardo, and G. Middlebrook. Am. Rev. Respir. Dis. 123:402-406. (1981).
For export only, not for redistribution in USA
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