Dog-DAT: a direct agglutination test using stabilized, freeze-dried antigen for the serodiagnosis of canine visceral leishmaniasis

We compared the performance of a locally produced β-mercaptoethanol-modified promastigote antigen (β-ME-Ag) of an indigenous Leishmania infantum strain against that of a trypsinized Leishmania donovani reference (REF-Ag) in the direct agglutination test (DAT) for detection of canine visceral leishmaniasis (CVL). One hundred and fifty-one serum samples collected from dogs belonging to four groups with different conditions were included. At a DAT titre of 1 : 320, statistically determined as optimal cut-off value for β-ME-Ag, and 1 : 160 for REF-Ag, a sensitivity and a specificity of 100 % were estimated for β-ME-Ag in comparison with 96.6 % and 100 %, respectively, for REF-Ag. Overall, levels of agglutination titres recorded for the two antigens were highly concordant (Cohen’s κ = 0.879) in both the CVL and non-CVL groups. Based on current results, and ease experienced in processing the antigen and reading the test outcome, we recommend incorporation of β-ME-Ag in DAT for confirmation or exclusion of suspected CVL in dogs.

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Evaluation of the direct agglutination test based on freeze-dried Leishmania donovani promastigotes for the serodiagnosis of visceral leishmaniasis in Sudanese patients

Tropical Medicine & International Health ◽

10.1111/j.1365-3156.2004.01308.x ◽

2004 ◽

Vol 9 (10) ◽

pp. 1127-1131 ◽

Cited By ~ 11

Author(s):

Khalid A. A. Abdallah ◽

Bakri Y. M. Nour ◽

Henk D. F. H. Schallig ◽

Adil Mergani ◽

Zohal Hamid ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Donovani ◽

Agglutination Test ◽

Direct Agglutination Test ◽

Freeze Dried

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Multicentre evaluation of a direct agglutination test prototype kit (DAT-LPC) for diagnosis of visceral leishmaniasis

Parasitology ◽

10.1017/s0031182017001378 ◽

2017 ◽

Vol 144 (14) ◽

pp. 1964-1970 ◽

Cited By ~ 9

Author(s):

E. OLIVEIRA ◽

D. OLIVEIRA ◽

F. A. CARDOSO ◽

J. R. BARBOSA ◽

A. P. MARCELINO ◽

...

Keyword(s):

Public Health ◽

Visceral Leishmaniasis ◽

Diagnostic Accuracy ◽

Antibody Test ◽

Agglutination Test ◽

Parasitic Infections ◽

Reference Laboratory ◽

Direct Agglutination Test ◽

Serum Samples ◽

Freeze Dried

SUMMARYIn this study, we assessed the sensitivity, specificity, and diagnostic accuracy of a previously developed direct agglutination test (DAT) using a freeze-dried antigen derived fromLeishmania infantumpromastigotes and composed in a prototype kit for visceral leishmaniasis (VL) diagnosis, named DAT-LPC. To evaluate DAT-LPC reproducibility, the kit was used to analyse 207 serum samples from VL patients and 80 serum samples from patients with other parasitic infections or healthy subjects in four laboratories from different public health institutions in Brazil. DAT-LPC showed sensitivity between 96·2 and 99·5% (P= 0·14), specificity ranging from 96·2 to 97·5% (P= 0·95), and diagnostic accuracy ranging from 96·5 to 99% (P= 0·34). The inter-laboratory reproducibility of qualitative results was classified as excellent (κindex: 0·94–0·97). The reproducibility of the end-titre results in relation to the reference laboratory, ranged from 31 to 85%. These results demonstrate an excellent performance of the DAT-LPC, and validate it for the diagnosis of VL that could replace the immunofluorescent antibody test as the routine diagnostic test in the Brazilian public health system.

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Comparative evaluation of freeze-dried and liquid antigens in the direct agglutination test for serodiagnosis of visceral leishmaniasis (ITMA-DAT/VL)

Tropical Medicine & International Health ◽

10.1111/j.1365-3156.2006.01743.x ◽

2006 ◽

Vol 11 (12) ◽

pp. 1777-1784 ◽

Cited By ~ 32

Author(s):

Diane Jacquet ◽

Marleen Boelaert ◽

Jill Seaman ◽

Suman Rijal ◽

Shyam Sundar ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Comparative Evaluation ◽

Agglutination Test ◽

Direct Agglutination Test ◽

Freeze Dried

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The direct agglutination test for diagnosis of visceral leishmaniasis under field conditions in Sudan: comparison of aqueous and freeze-dried antigens

Transactions of the Royal Society of Tropical Medicine and Hygiene ◽

10.1016/s0035-9203(97)90518-6 ◽

1997 ◽

Vol 91 (6) ◽

pp. 671-673 ◽

Cited By ~ 17

Author(s):

E.E. Zijlstra ◽

O.F. Osman ◽

H.W.Chr. Hofland ◽

L. Oskam ◽

H.W. Ghalib ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Agglutination Test ◽

Field Conditions ◽

Direct Agglutination Test ◽

Freeze Dried

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Evaluation of a glycerol-preserved antigen in the direct agglutination test for diagnosis of visceral leishmaniasis at rural level in eastern Sudan

Journal of Medical Microbiology ◽

10.1099/jmm.0.46753-0 ◽

2006 ◽

Vol 55 (10) ◽

pp. 1343-1347 ◽

Cited By ~ 10

Author(s):

Mohamed el Mutasim ◽

Durria Mansour ◽

Elfadil M. Abass ◽

Wisam M. Hassan ◽

Abdallah el Harith

Keyword(s):

Visceral Leishmaniasis ◽

Freeze Drying ◽

Weighted Kappa ◽

Agglutination Test ◽

Direct Agglutination Test ◽

Ambient Conditions ◽

Diagnostic Reliability ◽

Peripheral Hospital ◽

Freeze Dried ◽

Eastern Sudan

Three-hundred and eight patients with suspected visceral leishmaniasis (VL) were received at Doka Hospital (eastern Sudan) during the period September 2004 to October 2005. The sensitivity and specificity of a glycerol-preserved (GP) antigen for VL diagnosis was assessed against the results of repeated lymph node aspiration and readings from a direct agglutination test (DAT) employing standard formaldehyde-fixed (FF) or freeze-dried (FD) antigen. Despite 13 months of storage at ambient temperature (28–47 °C), the GP antigen mean titres obtained from these 308 patients were no different from those that were FD (P=0.945) and stored under similar conditions, but were significantly different (P=0.019) from those that were FF and kept continuously at the optimum temperature for storage (4–8 °C). Taking the parasitological result as the gold standard and using a pre-established titre of 1 : 3200 as the DAT cut-off, the GP antigen revealed a sensitivity (91/105, 86.7 %) and specificity (187/203, 92.1 %) comparable to that of FD antigen (92/105, 87.6 %, and 188/203, 92.6 %, respectively) and FF antigen (94/105, 89.5 %, and 188/203, 92.6 %, respectively). At a titre range of 1 : 400–1 : 800, statistically determined as the optimum cut-off for the three antigens, sensitivities of 92.4, 90.5 and 96.2 % and specificities of 90.6, 90.1 and 88.7 % were achieved for the GP, FD and FF antigens, respectively, at a peripheral hospital. Regardless of the antigen preparation used, DAT results obtained in the peripheral hospital were highly reproducible in the central laboratory in Omdurman (weighted kappa: GP=0.957, FD=0.979 and FF=0.936). With a diagnostic reliability comparable to formaldehyde fixation and stability under ambient conditions similar to freeze drying, glycerol preservation, by virtue of its high potential for reproduction, meets the requirements for the management of VL in developing countries.

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