Commercial Kits Evaluated for Mediterranean Visceral Leishmaniasis
By LabMedica International staff writers Posted on 16 Apr 2020 |
Image: An enzyme-linked immunosorbent assay (ELISA) kit for the diagnosis of visceral leishmaniasis in humans (Photo courtesy of Bordier Affinity Products)
Human visceral leishmaniasis (VL) is a neglected disease endemic in the Mediterranean region, caused by Leishmania infantum. Accurate VL diagnosis is critical for rapid and correct patient management. Dogs are the main reservoir of L. infantum parasites that are transmitted to humans by the bite of infected phlebotomine sand flies.
Parasite detection by microscopic examination of bone marrow aspirates is the gold standard method, but lacks sensitivity and requires invasive procedures. The culture of parasites isolated from patients might improve the diagnostic sensitivity. Various methods are used for VL serodiagnosis and molecular tests have been employed.
A team of scientists at the Université de Montpellier (Montpellier, France) and their international colleagues tested serum samples from 319 patients living in France, Tunisia or Morocco. The population of 181 with proven VL included 65 immunocompromised patients.
The serum samples were tested with two immunochromatographic tests (ICT): IT LEISH and TruQuick LEISH IgG/IgM (Meridianbioscience, Cincinnati, OH, USA) and four enzyme-linked immunosorbent assay (ELISA) reagents: NovaLisa Leishmania infantum IgG (NovaTec Immundiagnostica GmbH, Dietzenbach, Germany); Bordier Leishmania infantum (Bordier Affinity Products SA, Crissier, Switzerland); Ridascreen Leishmania IgG (R-Biopharm AG, Darmstadt, Germany); and Vircell Leishmania (Vircell, Granada, Spain).
The team reported that significantly higher percentages of false-negative results were obtained with all assays in immunocompromised patients, compared with the immunocompetent population. In the whole population, sensitivity and specificity ranged from 80.7% to 93.9% and from 95.7% to 100%, respectively. The maximum accuracy was observed with the Bordier and Vircell ELISA kits (96.2%), and the lowest accuracy with Ridascreen reagent (88.7%). New thresholds of positivity are proposed for the Bordier, Vircell and NovaLisa ELISA kits to achieve 95% sensitivity with the highest possible specificity. Western blot (WB), used as a confirmation method, showed 100% sensitivity and identified 10.1% of asymptomatic carriers among the control population from the South of France.
The authors concluded that the Vircell and Bordier ELISA kits displayed significantly higher accuracy rates in the whole population than the other tests. For field studies, the TruQuick ICT is the most suitable with satisfactory performances. In immunocompromised patients, the index values of all ELISA reagents were significantly lower than in the immunocompetent population and false-negative results were more frequent. The study was published on March 25, 2020 in the journal PLOS Neglected Tropical Diseases.
Parasite detection by microscopic examination of bone marrow aspirates is the gold standard method, but lacks sensitivity and requires invasive procedures. The culture of parasites isolated from patients might improve the diagnostic sensitivity. Various methods are used for VL serodiagnosis and molecular tests have been employed.
A team of scientists at the Université de Montpellier (Montpellier, France) and their international colleagues tested serum samples from 319 patients living in France, Tunisia or Morocco. The population of 181 with proven VL included 65 immunocompromised patients.
The serum samples were tested with two immunochromatographic tests (ICT): IT LEISH and TruQuick LEISH IgG/IgM (Meridianbioscience, Cincinnati, OH, USA) and four enzyme-linked immunosorbent assay (ELISA) reagents: NovaLisa Leishmania infantum IgG (NovaTec Immundiagnostica GmbH, Dietzenbach, Germany); Bordier Leishmania infantum (Bordier Affinity Products SA, Crissier, Switzerland); Ridascreen Leishmania IgG (R-Biopharm AG, Darmstadt, Germany); and Vircell Leishmania (Vircell, Granada, Spain).
The team reported that significantly higher percentages of false-negative results were obtained with all assays in immunocompromised patients, compared with the immunocompetent population. In the whole population, sensitivity and specificity ranged from 80.7% to 93.9% and from 95.7% to 100%, respectively. The maximum accuracy was observed with the Bordier and Vircell ELISA kits (96.2%), and the lowest accuracy with Ridascreen reagent (88.7%). New thresholds of positivity are proposed for the Bordier, Vircell and NovaLisa ELISA kits to achieve 95% sensitivity with the highest possible specificity. Western blot (WB), used as a confirmation method, showed 100% sensitivity and identified 10.1% of asymptomatic carriers among the control population from the South of France.
The authors concluded that the Vircell and Bordier ELISA kits displayed significantly higher accuracy rates in the whole population than the other tests. For field studies, the TruQuick ICT is the most suitable with satisfactory performances. In immunocompromised patients, the index values of all ELISA reagents were significantly lower than in the immunocompetent population and false-negative results were more frequent. The study was published on March 25, 2020 in the journal PLOS Neglected Tropical Diseases.
Latest Microbiology News
- Enhanced Rapid Syndromic Molecular Diagnostic Solution Detects Broad Range of Infectious Diseases
- Clinical Decision Support Software a Game-Changer in Antimicrobial Resistance Battle
- New CE-Marked Hepatitis Assays to Help Diagnose Infections Earlier
- 1 Hour, Direct-From-Blood Multiplex PCR Test Identifies 95% of Sepsis-Causing Pathogens
- Mouth Bacteria Test Could Predict Colon Cancer Progression
- Unique Metabolic Signature Could Enable Sepsis Diagnosis within One Hour of Blood Collection
- Groundbreaking Diagnostic Platform Provides AST Results With Unprecedented Speed
- Simple Blood Test Combined With Personalized Risk Model Improves Sepsis Diagnosis
- Blood Analysis Predicts Sepsis and Organ Failure in Children
- TB Blood Test Could Detect Millions of Silent Spreaders
- New Blood Test Cuts Diagnosis Time for Nontuberculous Mycobacteria Infections from Months to Hours
- New Tuberculosis Test to Expand Testing Access in Low- and Middle-Income Countries
- Rapid Test Diagnoses Tropical Disease within Hours for Faster Antibiotics Treatment
- Rapid Molecular Testing Enables Faster, More Targeted Antibiotic Treatment for Pneumonia
- Rapid AST Platform Provides Targeted Therapeutic Results Days Faster Than Current Standard of Care
- New Analysis Method Detects Pathogens in Blood Faster and More Accurately by Melting DNA