Leptospira antibody Test

A leptospira antibodies test is performed to diagnose leptospirosis. The test helps to differentiate leptospirosis from similar infections such as falciparum malaria, dengue fever, scrub typhus, typhoid and viral hepatitis. The symptoms of leptospirosis usually appear 10 days after infection but may develop anytime from two to 30 days of exposure to the bacteria. 

The first phase of the infection lasts for about five to seven days, with relatively mild symptoms such as:

• Fever
• Chills
• Muscle aches
• Headaches
• Cough
• Nausea
• Vomiting
• Loss of appetite

In rare cases, a second phase of infection occurs three to four days after the initial symptoms subside. This phase is marked by severe symptoms and organ damage and is known as Weil’s disease. The following symptoms may be seen in the second phase:

• Yellowish discolouration of the skin and eyes (jaundice)
• Kidney failure
• Lung problems
• Meningitis (inflammation of the lining of the brain)
• Irregular heartbeat
• Red eyes

You don't need any preparations for this test. Inform your doctor about any medications that you are consuming.

Your healthcare practitioner or a nurse will withdraw a small amount of your blood in a small vial. 

This procedure does not take more than a few minutes. After the test, you may experience mild pain or bruising at the site, but these symptoms fade away soon. If the bruising or discomfort persists, please inform your doctor.

A microscopic agglutination test (MAT) is done to identify the leptospira serovar and to assess the antibody titre against the serovar.

Normal results:

When the antibody titre is less than 50 for each serovar, the result is reported as normal. A normal result indicates that you don’t have a leptospirosis infection or the levels of antibodies are too low to be detected - this occurs in the early stages of infection. 

If you show all the symptoms of leptospirosis, your healthcare practitioner may repeat the test in 10-14 days - the antibodies may take up to 14 days, or sometimes longer, to appear.

Abnormal results:

Abnormal results are interpreted as follows:

• If the antibody titre is greater than 50 but not significantly high, it is reported as a low titre. Low titres may indicate an early stage infection. However, they can also be due to a previous infection because antibody levels drop gradually following the infection and low levels can persist up to 10 years after the infection.
• If the antibody titre is significantly high (≥ 400) or higher than a previous titre, it indicates probable recent infection. If two samples are tested within 10-14 days, a rise in titre of fourfold or more in the second sample compared to the first confirms recent infection. Although a single high titre also indicates recent infection, it is not diagnostic because high titres may persist for several months after infection.

The results may also be interpreted based on the phase of the disease.

• IgM titre of greater than 1:200 in the acute phase of the infection (the first week) is suggestive of leptospirosis.
• A fourfold rise in IgG antibody titre in the convalescent phase of the infection (after the first week) confirms leptospirosis.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.