Information for Healthcare Workers
The leptospirosis diagnostic serology service is located within the Department of Microbiology at Monash University, Melbourne and performs testing for human leptospirosis for Victoria, Australia. It is accredited for testing by the National Association of Testing Authorities and by the Royal College of Pathologists of Australasia.
We perform the Microscopic Agglutination Test (MAT). This test detects antibodies specific for the leptospira bacteria and is the World Health Organisation (WHO) gold standard test to diagnose leptospirosis. WHO also recommends MAT confirmation of all sera that has tested positive for leptospiral DNA using polymerase chain reaction (PCR). Using the MAT test we can determine the infecting serovar and the level of leptospiral antibodies present in the sera. Currently we test for antibodies against the following serovars: Arborea, Australis, Canicola, Copenhageni, Grippotyphosa, Hardjo, Pomona, Tarassovi and Zanoni. These serovars have been carefully chosen based on epidemiological data of leptospirosis disease in the Australasian area.
Other tests for Leptospirosis
Other tests for leptospirosis include an IgM ELISA, PCR or direct culture. The IgM test detects early production of antibodies (IgM) and therefore can become positive earlier than the MAT, but suffers from both false positive and false negative problems. It also gives no indication of the infecting serovar and therefore cannot provide potentially important epidemiological information. Reliance on ELISA alone is not recommended. PCR tests to detect leptospiral DNA are also available. However, like all diagnostic PCRs, a negative result does not necessarily mean that the patient has not been infected as PCR can fail to generate a product for a variety of reasons. Additionally, the PCR test cannot give information on infecting serovar or the current status of infection. Direct culture of leptospires from urine or serum takes time and is very difficult, with an extremely low success rate. It is therefore not a recommended practice for diagnosis of disease in individual patients.
|Information for Patients||Payment Options|
A blood sample for leptospirosis serology should be taken as soon as the patient presents to a clinic/hospital with a febrile illness and leptospirosis is considered a possible cause. A second specimen should be taken 5-7 days later if the clinical picture & history indicate significant possibility of leptospira infection. Further tests may be conducted with sera taken at similar intervals if necessary.
|Specimen Collection and Transport|
|Test Name||Leptospirosis Serology|
|Laboratory and delivery details||Leptospirosis Serology (Boyce Laboratory)
via Medicine Store
G55, 23 Innovation Walk (Building 77)
Monash University, Clayton Campus
|Specimen Type/Volume||Serum at least 0.2 ml|
|Container and Storage||Plain tube at room temperature|
|Details||Tests for antibody to Leptospira serovars|
Interpretation of results
We provide three interpretations with our reports
1. "No antibodies detected against this panel of leptospiral serovars. Antibodies in leptospirosis may take up to 14 days, or longer, to appear. A second specimen is suggested in 10-14 days if a clinical/epidemiological suspicion of leptospirosis persists."
This interpretation is provided when the titres for each of the serovars tested is < 50. There may be no infection or no detectable levels of antibodies because the patient is in the early stages of infection. Antibodies appear 7-10 days into the infection but sometimes antibodies do not appear until 3-4 weeks after infection, or very rarely, even longer.
2. "This low titre may represent either residual antibody from a past infection or early antibody in a current infection. A repeat specimen is suggested if diagnosis is not established."
This interpretation is provided when the titre for antibodies against a particular serovar is greater than 50 but the titre is not considered high. This low antibody level may indicate the patient is in the early stages of infection. Alternatively, low antibody levels may indicate a previous infection. This is because over time, antibody levels gradually drop following infection but low levels may persist for up to 10 years post-infection.
3. "Probable recent infection".
This interpretation is provided when the titre for antibodies against a serovar is high or higher than the previous titre in serum from the same patient. If two samples are provided (10-14 days apart) and the infection is current, a second specimen may be positive (when the first was negative) or show a rise in titre compared with the titre of the first sample. A rising titre of 4-fold or greater is diagnostic of a recent infection. A single high titre can also indicate a recent infection but antibodies can often remain high (titre ≥ 400) for many months following an infection.
The Leptospirosis Laboratory may be contacted at:
Telephone: +61 3 9902 9193
Fax: +61 3 9902 9224
Mailing Address: Leptospirosis Laboratory, Department of Microbiology, 19 Innovation Walk, Wellington Road, Clayton, Victoria, 3800