What is the role of the Leishmanin skin test (Montenegro test) in the workup of leishmaniasis?

Updated: Feb 18, 2020
  • Author: Craig G Stark, MD, FACP, FFTM, RCPS(Glasg), FISTM; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Answer

No skin tests for leishmaniasis are approved for use in the United States, primarily due to the lack of standardization of these tests.

The Leishmanin skin test (LST), also known as the Montenegro skin test (for its introduction in Montenegro, South America) is similar to the purified protein derivative (PPD) used for Mycobacterium tuberculosis. This test has been used in the developing world to determine delayed-type hypersensitivity reactions.

Killed promastigotes are injected intradermally; a 5-mm area of induration over 48-72 hours suggests past infection (ie, results are negative during active visceral leishmaniasis; positive results occur 2-3 months after infection, usually after successful therapy. The test results are also positive in patients with post–kala-azar dermal leishmaniasis).

The 2 main drawbacks of this test are that acute infections cannot be identified (in endemic regions, >70% of the population will test positive), because it remains positive for life, and those who are immunosuppressed (immunologically anergic patients) may not mount a response. Thus, this test is not used to distinguish between active and resolved disease, but it can be useful in evaluating known naive populations that become immunologically responsive to leishmanial antigens (ie, epidemiologic purposes).


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