How does LYME DISEASE test work?
In presence of Borrelia bacterium transmitted by a tick, specific IgM antibodies are produced first by the immune system. The antibodies circulate in the blood and bind on the encountered bacteria. The Borrelia antigens coated on the LYME DISEASE strip specifically detect those antibodies by producing a coloured line under the T mark of the cassette. A control line capturing the reagent excess appears as a coloured line under the C mark of the cassette. In case both lines appear, the presence of Borrelia bacterium can be suspected.
When should the test be used?
LYME DISEASE test should be performed between 2 and 6 weeks after being bitten by a tick or as soon as a round inflammation (erythema) appears on a part of the body likely which was exposed to a tick bite. It corresponds to the phase 1 of the disease for which the LYME DISEASE is well suitable and for which the test sensitivity is 53.8%. Contamination happens only in 1 to 2% of the cases, but the presence of IgM antibodies, detected thanks to a positive result, indicates an infection that should be rapidly treated.
Ticks are insects living in undergrowth and forests of temperate climatic zones. Those insects can be infected by a bacterium (Borrelia) that can be then transmitted to humans (1 to 2% transmission risk) after being bitten on the arm, the leg and any other part of the body not protected with clothes. Borrelia bacterium affects the nervous system and can lead to serious neurological disorders. European strains of Borrelia include B. afzelli, B. garinii, B. burgdoferi sensu stricto B. spielmanii, and B. bavariensis which are known pathogenic. Species B. valaisiana and B. lusitaniae are potentially pathogenic. That infection can also cause cutaneous lesions and arthritis. From 3 to 10 days, or even several weeks, after being bitten, an inflammation and redness (erythema) can appear in the bite region. The inflammation can be accompanied by feverishness.
In case of infection, the immune system reacts by releasing specific antibodies directed against Borrelia bacterium. A particular category of antibodies (IgM: immunoglobulins M) which appears first can be detected between 2 and 6 weeks after being infected. Lyme disease develops in 3 stages: In phase I (2 to 4 weeks), The IgM antibodies appear only in 40 to 60 % of the cases. During the phase II (4 to 6 weeks later), the antibodies are detectable in 70 to 90 % of the cases. At last during phase III, the antibodies are generally present and can be detected.
Using LYME DISEASE test, it is possible to detect the presence of those specific IgM antibodies which appears first, and thus, a recent infection with Borrelia bacterium between 2 and 4 weeks after the presumed tick bite. Should the case arise, an antibiotic therapy will eliminate the infection.
Attention: However, this screening test cannot detect the stage of the illness in case of positive results.
The box contains the material needed to perform a test:
– 1 sealed aluminium pouch containing:
1 test device, 1 plastic pipette and 1 desiccant pouch.
Only open the protective pouch when you are ready to use the test. The desiccant pouch should not be used.
– 1 sterile lancet for blood sampling.
– 1 diluent vial of 1 mL of diluent.
– 1 instruction leaflet.
- This test is exclusively intended to in vitro diagnostic use. External use only. DO NOT SWALLOW.
- Carefully read the instructions before performing the test. The test is only interpretable if the instructions are carefully respected. Follow strictly the indicated blood and diluent quantities, as well as reading times.
- Store between +4°C and +30°C. Do not freeze the test.
- Do not use after the expiry date printed on the label and on the protective pouch or if this pouch is damaged.
- Do not reuse the LYME DISEASE test.
- Keep out of reach of children.
- After use, all the components can be discarded in a dustbin.
Testing procedure always starts with a good preparation. Place the content of the box on a clean, dry and flat surface (e.g. table). Then the testing follows:
- Wash your hands thoroughly. Use soap and warm water. Dry your hand with clean towel.
- Prepare the test device and the pipette. Take them out from the protective pouch (tear at the notch) and place them in the reach of your hands (you will need them later). Dispose the small dessicant bag.
- Prepare the lancet. Hold the lancet without touching the trigger button. Unlock the lancet cap twisting it off ¼ turn until you feel it separates from the lancet and then continue twisting it (2-3 rotations). Don’t pull just twist and discard the cap when finished.
- Clean the end of the forefinger or of the middle finger with cotton damped with alcohol. Rub the chosen finger towards the tip to later on enhance the blood stream.
- Press platform firmly against the previously cleaned finger, and press the release trigger button.
- The tip will automatically retract into the body of the device.
- Rub the finger’s end to obtain enough whole blood sample.
- Without pressing the bulb, put in contact the plastic pipette with the blood sample. The blood migrates into the pipette through capillarity to the line indicated on the pipette. You may rub again your finger to obtain more blood if the line is not reached. As far as possible, avoid air bubbles.
- Put the blood collected with the pipette into the sample well of the device, by pressing on the pipette bulb.
- Wait 30-40 sec for the blood being totally absorbed into the sample well. Unscrew the blue cap of the diluent vial (leave the white cap tightly screwed) and add the diluent as follows: Hold the diluent vial vertically and slowly add exactly 4 drops in the sample well of the device with an interval of 2-3 seconds between each drop.
- Read the result after 10 minutes. Do not interpret after 15 minutes.
The intensity of the line colour does not have any importance for the interpretation of the test result.
- Negative result
Only one coloured line appears under the mark C (Control). This result means that no antibodies directed against Borrelia bacterium are detectable in blood.
- Positive result
Two coloured lines appear in the window under the marks T (Test) and C (Control). The intensity of the line T may be clearer than the intensity of the line C. This result means that IgM antibodies directed against Borrelia bacterium are present in blood and an infection is starting. You must absolutely consult your doctor.
- Non valid result
No line appears or a coloured line appears under the mark T (Test) without any line under the mark C. In this case, it is not possible to interpret the test, which must be considered as non-valid. It is recommended to repeat the test with a new Lyme disease test device and a fresh whole blood sample.
QUESTIONS AND ANSWERS
Can the result be incorrect?
The results are accurate as far as the instructions are carefully respected. Nevertheless, the result can be incorrect if LYME DISEASE test gets wet before test performing or if the quantity of blood dispensed in the sample well is not sufficient. The plastic pipette provided in the box allows making sure the collected blood volume is correct.
How to interpret the test if the colour and the intensity of the lines are different?
The colour and intensity of the lines have no importance for result interpretation. The lines should only be homogeneous and clearly visible. The test should be considered as positive whatever the colour intensity of the test line is.
What is the line that appears under the mark C (Control) for?
When this line appears, it only means that the test was performing well.
If I read the result after 15 minutes, will the result be reliable?
No. The result should be read within 10 minutes after adding the diluent. The result is reliable up to 15 minutes.
What do I have to do if the result is positive?
If the result is positive, it means that IgM antibodies directed against Borrelia bacterium are detectable in blood and that you must absolutely consult a doctor showing him the test result. Then, the doctor will order a treatment to follow in order to avoid complications arising after this infection. In case of past infection having occured several years before, a positive result can be obtained as the antibodies may be persisting in some persons. A positive result can also be obtained in patient having been efficiently cured with antibiotics.
What do I have to do if the result is negative?
If the result is negative, it means that no IgM antibodies directed against Borrelia bacterium are detectable in blood.
Caution: Falsely negative results can be observed during phase I (antibodies appearing in 40 to 60% of the cases) or during phase II (antibodies rising in 70 to 90% of the cases) of the disease development. In case of negative result it is strongly recommended to perform a new test 2 to 4 weeks later in order to check the increase of antibodies level. If you have been preventively treated by antibiotics, the antibodies are not detectable or cannot be detected.
If the tick’s bite is too recent (less than 2 weeks), your organism has not had enough time to produce detectable antibodies. It is recommended to repeat the test with a new Lyme disease test 2 to 4 weeks after the presumed bite. However, if a rash, accompanied or not by feverishness, persists, it is recommended to consult your doctor.