a confirmed case, but titers as high as 1600 have been recommended [9]. MAT detects serogroup-specific antibodies IgM and
IgG, and the panel of antigens and live cultures should include
serovars representative of all serogroups and local strains. Alternatively, the WHO recommends 19 serovars of 16 serogroups [7]. Filter paper-dried serum samples can be used for MAT: their titers
were almost equal to those of fresh samples when stored at room
temperature for up to 7 days [41].
The principle of MAT is simple, but the procedure requires
technical expertise and the maintenance of a panel of Leptospira
cultures, and quality control must be employed [42]. Furthermore,
the sensitivity of MAT in the acute phase is low, and paired sera are
needed to confirm the diagnosis. Therefore, a number of rapid
screening tests for antibody detection in acute infection, such as
macroagglutination test, indirect hemagglutination assay, immunofluorescence assay, microcapsule agglutination test, enzyme-linked
immunosorbent assay (ELISA), dot enzyme immunoassay (dipstick), lateral flow assay (LFA), and latex agglutination test, have
been developed [9, 17, 43], and some of the whole-cell-based assay
kits are commercially available (Table 2). These whole-cell-based
assays are believed to be genus-specific and detect IgM (and/or
IgG) antibodies from patients, regardless of infective serovars or
serogroups, with easy and rapid formats. These assays detected antileptospiral IgM in the earlier course of the disease than MAT but
still have low sensitivity during the acute phase. In addition, several
recent studies using currently available kits indicate that the diagnostic accuracies of these techniques are poor in some areas where
leptospirosis is endemic [44–47]. This may be attributed to the
persistence of anti-leptospiral IgM after infection, recurrent infection in endemic areas, or cross-reaction with other infectious
microorganisms. A meta-analysis of the published literature on
ELISA also indicated high heterogeneity in the overall sensitivity
and specificity estimates, whereas that on LFA showed that the
evidence base for the diagnostic accuracy of LFA is at risk of bias
[48, 49]. Therefore, the confirmation of rapid serological test
results by MAT, NAAT, and/or culture is strongly recommended
[48, 50]. Furthermore, as pointed out previously [17, 51], training
of laboratory personnel is important even in the simple-to-interpret
platform assays due to the considerable inter-observer variability in
reading the test results [47]. To improve their diagnostic accuracy,
researchers suggested setting local cutoff values instead of suppliers’ definitions [43, 44, 52]. Furthermore, a new assay using
whole-cell antigens from the intermediate L. fainei showed good
diagnostic performance compared with whole-cell-based commercial kits [53].
Recombinant protein or peptide-based IgM assays such as
ELISA, latex agglutination test, dipstick assay, and Dual Path Platform have been developed [15, 54, 55], of which some assays
Laboratory Diagnosis of Leptospirosis
281
IgG, and the panel of antigens and live cultures should include
serovars representative of all serogroups and local strains. Alternatively, the WHO recommends 19 serovars of 16 serogroups [7]. Filter paper-dried serum samples can be used for MAT: their titers
were almost equal to those of fresh samples when stored at room
temperature for up to 7 days [41].
The principle of MAT is simple, but the procedure requires
technical expertise and the maintenance of a panel of Leptospira
cultures, and quality control must be employed [42]. Furthermore,
the sensitivity of MAT in the acute phase is low, and paired sera are
needed to confirm the diagnosis. Therefore, a number of rapid
screening tests for antibody detection in acute infection, such as
macroagglutination test, indirect hemagglutination assay, immunofluorescence assay, microcapsule agglutination test, enzyme-linked
immunosorbent assay (ELISA), dot enzyme immunoassay (dipstick), lateral flow assay (LFA), and latex agglutination test, have
been developed [9, 17, 43], and some of the whole-cell-based assay
kits are commercially available (Table 2). These whole-cell-based
assays are believed to be genus-specific and detect IgM (and/or
IgG) antibodies from patients, regardless of infective serovars or
serogroups, with easy and rapid formats. These assays detected antileptospiral IgM in the earlier course of the disease than MAT but
still have low sensitivity during the acute phase. In addition, several
recent studies using currently available kits indicate that the diagnostic accuracies of these techniques are poor in some areas where
leptospirosis is endemic [44–47]. This may be attributed to the
persistence of anti-leptospiral IgM after infection, recurrent infection in endemic areas, or cross-reaction with other infectious
microorganisms. A meta-analysis of the published literature on
ELISA also indicated high heterogeneity in the overall sensitivity
and specificity estimates, whereas that on LFA showed that the
evidence base for the diagnostic accuracy of LFA is at risk of bias
[48, 49]. Therefore, the confirmation of rapid serological test
results by MAT, NAAT, and/or culture is strongly recommended
[48, 50]. Furthermore, as pointed out previously [17, 51], training
of laboratory personnel is important even in the simple-to-interpret
platform assays due to the considerable inter-observer variability in
reading the test results [47]. To improve their diagnostic accuracy,
researchers suggested setting local cutoff values instead of suppliers’ definitions [43, 44, 52]. Furthermore, a new assay using
whole-cell antigens from the intermediate L. fainei showed good
diagnostic performance compared with whole-cell-based commercial kits [53].
Recombinant protein or peptide-based IgM assays such as
ELISA, latex agglutination test, dipstick assay, and Dual Path Platform have been developed [15, 54, 55], of which some assays
Laboratory Diagnosis of Leptospirosis
281