Microbiology Test

Test : Leptospirosis, Darkfield Examination,


Indications : The test is ordered when leptospirosis is suspected or to detect the presence of leptospira in case of Weil's syndrome, hemorrhagic fever with renal syndrome, atypical pneumonia syndrome, aseptic meningitis, and myocarditis including cardiac arrhythmias.

Samples for the test include blood, peritoneal and pleural exudates, urine or CSF. The samples must be sent to the lab without any delay. They must never be frozen. During the early stages of the disease the bacteria is found in the blood and CSF. Later on, it is detected in the infected sites or urine.

Direct examination of the sample through microscope can be done. A drop of sample is placed on the micro slide and observed through high power. Dark field microscopy must be avoided to prevent confusion.

Physiology : Leptospirosis is a rare but severe infection caused by the bacteria, Leptospira which abounds in freshwater contaminated with animal urine. The bacteria are more prevalent in warmer climate. It does not usually spread through touch but, can pass from a mother to her unborn child during childbirth or, to the child of a nursing mother through breast milk. Symptoms include dry cough, fever and muscle pain and can take an average of ten days to develop.

Normal Range : No presence of Leptospira species

Interpretation : Microscopic examination of an infected sample within ten days of infection will reveal the presence of leptospira. The advantage of direct observation is early detection. Once leptospira presence is detected it may be confirmed through culture. Normal samples will lack the presence of leptospira bacteria.

Sample : Urine, serum, cerebrospinal fluid

Test Method : Dark field microscopy

Related Tests : Leptospira culture, Leptospira serodiagnosis.

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