Leishmania infection: laboratory diagnosing in the absence of a "gold standard".
There is no gold standard for diagnosing leishmaniases. Our aim was to assess the operative validity of tests used in detecting Leishmania infection using samples from experimental infections, a reliable equivalent to the classic definition of gold standard. Without statistical differences, the highest sensitivity was achieved by protein A (ProtA), immunoglobulin (Ig)G2, indirect fluorescenece antibody test (IFAT), lymphocyte proliferation assay, quantitative real-time polymerase chain reaction of bone marrow (qPCR-BM), qPCR-Blood, and IgG; and the highest specificity by IgG1, IgM, IgA, qPCR-Blood, IgG, IgG2, and qPCR-BM. Maximum positive predictive value was obtained simultaneously by IgG2, qPCR-Blood, and IgG; and maximum negative predictive value by qPCR-BM. Best positive and negative likelihood ratios were obtained by IgG2. The test having the greatest, statistically significant, area under the receiver operating characteristics curve was IgG2 enzyme-linked immunosorbent assay (ELISA). Thus, according to the gold standard used, IFAT and qPCR are far from fulfilling the requirements to be considered gold standards, and the test showing the highest potential to detect Leishmania infection is Leishmania-specific ELISA IgG2.
Rodríguez-Cortés
Alhelí
A
Unitat de Farmacologia Veterinària and LeishLAB-Servei d'Anàlisi de Fàrmacs, Departament de Farmacologia, de Terapèutica i de Toxicologia, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain. Alheli.Rodriguez@uab.cat
Ojeda
Ana
A
Francino
Olga
O
López-Fuertes
Laura
L
Timón
Marcos
M
Alberola
Jordi
J
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D001853:Bone Marrow / Q000469:parasitology; D049109:Cell Proliferation; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D007136:Immunoglobulins; D007891:Leishmania / Q000276:immunology*; D007896:Leishmaniasis / Q000175:diagnosis* / Q000276:immunology; D008214:Lymphocytes / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D000913:Antibodies, Protozoan; D007136:Immunoglobulins