Comparative evaluation of assays for IgM detection of rubella and measles infections.

BACKGROUND: Serological diagnosis of infections due to measles and rubella viruses is done by IgM detection. The aim of this study was to comparatively evaluate commercial systems for detecting IgM against both viruses, including those of ELISA, in indirect and capture formats, chemiluminescence and electrochemiluminescence. METHODS: Seven (for rubella) and six (for measles) assays were studied. One hundred and sixty two samples were included in the study (from 90 rubella and 72 measles cases), and all were analyzed in all the assays. RESULTS: The ranges of sensitivity, specificity and agreement for rubella were 94.8-100%, 52.4-100% and 75.5-98.1%, respectively. The corresponding ranges for measles assays were 87.0-100%, 53.3-100%, and 73.0-99.4%. CONCLUSION: The best-performing assays were chemiluminescence (for measles and rubella IgM), and electrochemiluminescence (for rubella IgM).

Comparative evaluation of assays for IgM detection of rubella and measles infections / Evaluación comparativa de ensayos para la detección de IgM en infecciones por rubéola y sarampión

BackgroundSerological diagnosis of infections due to measles and rubella viruses is done by IgM detection. The aim of this study was to comparatively evaluate commercial systems for detecting IgM against both viruses, including those of ELISA, in indirect and capture formats, chemiluminescence and electrochemiluminescence.MethodsSeven (for rubella) and six (for measles) assays were studied. One hundred and sixty two samples were included in the study (from 90 rubella and 72 measles cases), and all were analyzed in all the assays.ResultsThe ranges of sensitivity, specificity and agreement for rubella were 94.8–100%, 52.4–100% and 75.5–98.1%, respectively. The corresponding ranges for measles assays were 87.0–100%, 53.3–100%, and 73.0–99.4%.ConclusionThe best-performing assays were chemiluminescence (for measles and rubella IgM), and electrochemiluminescence (for rubella IgM).

El diagnóstico serológico de las infecciones por los virus de la rubéola y del sarampión se realiza por detección de IgM específica. El objetivo de este estudio fue evaluar comparativamente sistemas comerciales para la detección de IgM frente a ambos virus, incluyendo ensayos de ELISA, tanto con metodologías indirectas como de captura, así como quimioluminiscencia y electroquimioluminiscencia.MétodosSe estudiaron 7 ensayos para rubéola y 6 para sarampión. Se emplearon 162 muestras (de 90 casos de rubéola y de 72 de sarampión) que se analizaron en todos los ensayos.ResultadosLos rangos de sensibilidad, especificidad y concordancia para los ensayos de rubéola fueron 94,8-100%, 52,4-100% y 75,5-98,1%, respectivamente. Los rangos correspondientes para los ensayos de sarampión fueron 87-100%, 53,3-100% y 73-99,4%, respectivamente.ConclusiónLos mejores ensayos fueron quimioluminiscencia (para IgM frente a rubéola y a sarampión) y electroquimioluminiscencia (para IgM frente a rubéola).

Comparative evaluation of assays for IgM detection of rubella and measles infections.

BACKGROUND: Serological diagnosis of infections due to measles and rubella viruses is done by IgM detection. The aim of this study was to comparatively evaluate commercial systems for detecting IgM against both viruses, including those of ELISA, in indirect and capture formats, chemiluminescence and electrochemiluminescence. METHODS: Seven (for rubella) and six (for measles) assays were studied. One hundred and sixty two samples were included in the study (from 90 rubella and 72 measles cases), and all were analyzed in all the assays. RESULTS: The ranges of sensitivity, specificity and agreement for rubella were 94.8-100%, 52.4-100% and 75.5-98.1%, respectively. The corresponding ranges for measles assays were 87.0-100%, 53.3-100%, and 73.0-99.4%. CONCLUSION: The best-performing assays were chemiluminescence (for measles and rubella IgM), and electrochemiluminescence (for rubella IgM).

Evaluation of the LIAISON XL Zika Capture IgM II for the Diagnosis of Zika Virus Infections.

The aim of this study is to evaluate the performance characteristics of the LIAISON XL Zika Capture IgM II. For this purpose we tested 128 samples obtained from recent infections caused by the Zika (ZIKV; 74 samples), dengue (DENV; 10 samples), chikungunya (CHIK V; 11 samples), rubella (RUBV; 10 samples) and measles (MeV; 10 samples) viruses, as well as human parvovirus B19 (HPVB19; 13 samples). The results of the assay under evaluation are compared with those obtained from an indirect immunofluorescence (IIF) assay, and the discrepancies are resolved by considering other laboratory results (PCR and a plaque-reduction neutralization test). The LIAISON showed excellent sensitivity (100%). The specificity (91.25%) was hampered by some false-positive results in recent dengue virus, chikungunya virus, measles virus and human parvovirus B19 infections. The method evaluated is adequate, but the low specificity makes it necessary to consider the clinical and epidemiological contexts of patients, as well as other laboratory results.

Comparison of commercial methods of immunoblot, ELISA, and chemiluminescent immunoassay for detecting type-specific herpes simplex viruses-1 and -2 IgG.

BACKGROUND: Serology for type-specific herpes simplex virus (HSV) is based on the use of the respective glycoprotein G (gG). METHODS: Chemiluminescent immunoassay (CLIA; BIO-FLASH® , Biokit, Spain), ELISA (HerpeSelect® , Focus, USA), and immunoblot (IB; Virotech, Germany) for detecting HSV-1- and HSV-2-specific IgG were compared using 384 serum samples received for HSV serology. The samples were classified as positive or negative according to a consensus criterion. RESULTS: For HSV-1, 262 samples were positive and 118 were negative (four samples were unclassifiable). IB showed agreement, sensitivity, and specificity values of 98.68%, 98.47% and 99.15%, respectively. The corresponding figures for CLIA and ELISA were 98.95%, 99.24% and 98.31%, and 98.16%, 99.62% and 94.92%, respectively. For HSV-2, 106 samples were positive and 278 were negative. Agreement, sensitivity, and specificity of IB were 99.48%, 98.11%, and 100%, respectively. The corresponding figures for CLIA and ELISA were 99.48%, 99.06% and 99.64%, and 98.18%, 99.06% and 97.84%, respectively. CONCLUSION: The three methods showed excellent and equivalent performance characteristics for the detection of type-specific IgG to HSV-1 and HSV-2.

Chikungunya virus infections among travellers returning to Spain, 2008 to 2014.

Since the first documented autochthonous transmission of chikungunya virus in the Caribbean island of Saint Martin in 2013, the infection has been reported within the Caribbean region as well as North, Central and South America. The risk of autochthonous transmission of chikungunya virus becoming established in Spain may be elevated due to the large numbers of travellers returning to Spain from countries affected by the 2013 epidemic in the Caribbean and South America, as well as the existence of the Aedes albopictus vector in certain parts of Spain. We retrospectively analysed the laboratory diagnostic database of the National Centre for Microbiology, Institute of Health Carlos III (CNM-ISCIII) from 2008 to 2014. During the study period, 264 confirmed cases, of 1,371 suspected cases, were diagnosed at the CNM-ISCIII. In 2014 alone, there were 234 confirmed cases. The highest number of confirmed cases were reported from the Dominican Republic (n = 136), Venezuela (n = 30) and Haiti (n = 11). Six cases were viraemic in areas of Spain where the vector is present. This report highlights the need for integrated active case and vector surveillance in Spain and other parts of Europe where chikungunya virus may be introduced by returning travellers.

Comparison of chemiluminescent immunoassay and ELISA for measles IgG and IgM.

In the context of measles elimination, the identification of recent infections is important for clinical laboratories. Serological diagnosis is achieved by detecting specific IgG and IgM. Recently an automated chemiluminescent immunoassay (CLIA) (Liaison, DiaSorin, Italy) has been used to quantify the measles antibody. The aim of this study was to compare this assay with Enzygnost ELISA (Siemens, Germany), with final classification of discrepancies by indirect immunofluorescence (Euroimmun, Germany). For measles IgM, 204 sera were analyzed: 50 IgM-positive, 104 IgM-negative/IgG-positive, and 50 from other viral infections (B19V, rubella, mumps, CMV, and EBV). For the measles IgG assay, 162 samples were tested: 106 were positive and 56 were negative. For measles IgM, the sensitivity and specificity of CLIA against ELISA were 94% (95% CI: 83.2-98.6) and 100% (95% CI: 97.1-100), respectively; the corrected figures after the final classification of discrepancies were 100% (95% CI: 91.0-100) and 99.4% (95% CI: 96.1-100), respectively. In relation to IgG, the sensitivity and specificity of CLIA against ELISA were, respectively, 97.2% (95% CI: 91.7-99.4) and 92.9% (95% CI: 82.5-97.7), and 95.5% (95% CI: 89.5-98.3) and 100% (95% CI: 91.8-100) after the final classification. CLIA showed excellent sensitivity and specificity in detecting measles IgG and IgM antibodies, eliminating the need to aliquot specimens before carrying out the assay.

Prevalence of antibody to Bordetella pertussis in neonates and prevalence of recent pertussis infection in pregnant women in Catalonia (Spain) in 2003 and 2013.

BACKGROUND: Infections because of Bordetella pertussis still occur in infants and adults in European countries, despite vaccination coverage against pertussis being high. METHODS: IgG antibody titers to pertussis toxin (anti-PT) were assessed using an enzyme-linked immunosorbent assay test (Serion ELISA classic) in 353 cord blood samples from neonates of a representative sample of pregnant women obtained in Catalonia (Spain) in 2013. Neonates with anti-PT titers ≤ 40 international units (IU)/mL were considered to be unprotected against pertussis. IgG-PT titers >100 IU/mL in umbilical cord samples were considered to be indicative of a current or recent pertussis infection (12 months) in pregnant women. The age-standardized prevalence of recent pertussis infection obtained in this study was compared with the prevalence obtained in 2003. RESULTS: The mean anti-PT titer in neonates was 10.8 IU/mL and 89.8% of neonates were unprotected against pertussis. The prevalence of unprotected neonates as defined by cord blood anti-PT ≤ 40 IU/mL was 90%. The prevalence of recent pertussis infection in pregnant women as defined by cord blood anti-PT >100 IU/mL was 2%. The diphtheria-tetanus-pertussis vaccination coverage during childhood in pregnant women was 75%. The age-standardized prevalence of recent pertussis infection in pregnant women observed in this study (2.2%) was slightly higher than the prevalence obtained in 2003 (1.5%), with an odds ratio = 1.45 (95% confidence intervals: 0.5-3.9), although differences were not statistically significant. CONCLUSIONS: Most neonates are unprotected against pertussis and pertussis infections are frequent in pregnant women in Catalonia. Infants and pregnant women should be the priority population groups for pertussis prevention programs in Catalonia.