6
Diagnosis
1. The Panel recommends using multiple diagnostic approaches to
maximize the likelihood of a positive Leishmania result, using
methods such as visualization of the characteristic amastigote in
smears or tissue (histopathology); parasite isolation by in vitro
culture; molecular detection of parasite DNA; and, for VL, serologic
testing (see Recs. 5, 6, 9, 21, 22 and Table 2). Simultaneous testing
for other diagnoses (eg, by histopathology and culture) should be
considered (S-L).
2. The Panel recommends attempting parasite isolation with the
assistance of reference laboratories. The Panel recommends that
clinicians contact their leishmaniasis reference laboratory before
collecting specimens (Table 2). If Leishmania parasites are isolated
in culture, reference laboratories can identify the species by DNA-
based assays or isoenzyme analysis (S-L).
3. Molecular amplification assays typically should be performed
because they are the most sensitive Leishmania tests currently
available (see Recs. 6) (S-M).
4. Leishmania skin testing is NOT recommended or available in the
United States or Canada. There are no standardized, approved, or
commercially available skin-test products in North America (S-VL).
5. The Panel suggests that identification of the infecting parasite to
the species level be attempted in cases of suspected CL. Species
identification may help inform clinical management decisions for
individual persons (eg, whether and how to treat) (W-M).
6. DNA-based assays should be performed, especially if other
diagnostic testing is unrevealing. They are emerging as the most
sensitive assays for the diagnosis of leishmaniasis (S-M).
