The European Sero-Epidemiology Network: standardizing the 
enzyme immunoassay results for measles, mumps and rubella

The ESEN (European Sero-Epidemiology Network) project was established to harmonize the seroepidemiology of five vaccine preventable infections including measles, mumps and rubella in eight European countries. This involved achieving comparability both in the assay results from testing in different centres and also sampling methodology. Standardization of enzyme immunoassay results was achieved through the development of common panels of sera by designated reference centres. The panels were tested at the reference laboratory and then distributed to each participating laboratory for testing using their routine methods. Standardization equations were calculated by regressing the quantitative results against those of the reference laboratory. Our study found large differences in unitage between participants, despite all using an EIA method standardized against an international or local standard. Moreover, our methodology adjusted for this difference. These standardization equations will be used to convert the results of main serosurvey testing into the reference country unitage to ensure inter-country comparability.

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Standardization of measles, mumps and rubella assays to enable comparisons of seroprevalence data across 21 European countries and Australia

Epidemiology and Infection ◽

10.1017/s0950268807008266 ◽

2007 ◽

Vol 135 (5) ◽

pp. 787-798 ◽

Cited By ~ 38

Author(s):

A. TISCHER ◽

N. ANDREWS ◽

G. KAFATOS ◽

A. NARDONE ◽

G. BERBERS ◽

...

Keyword(s):

Enzyme Immunoassay ◽

Neutralization Test ◽

European Countries ◽

Reference Laboratory ◽

Vaccine Preventable Diseases ◽

Seroprevalence Data ◽

Serological Surveillance ◽

Quantitative Results ◽

Country Differences ◽

Almost All

SUMMARYThe aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations withR2⩾0·8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95·3%, 92·8% and 100% and a specificity of 100%, 87·1% and 92·8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countries.

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Enzyme immunoassay of carbamazepine with a centrifugal analyzer.

Clinical Chemistry ◽

10.1093/clinchem/25.2.295 ◽

1979 ◽

Vol 25 (2) ◽

pp. 295-298 ◽

Cited By ~ 3

Author(s):

D A Lacher ◽

R Valdes ◽

J Savory

Keyword(s):

Enzyme Immunoassay ◽

Sample Volume ◽

Gas Liquid Chromatography ◽

Good Precision ◽

Concentration Data ◽

Kinetic Rate ◽

Analytical Recovery ◽

Assay Time ◽

Quantitative Results ◽

Carbamazepine Concentration

Abstract We describe a rapid enzyme immunoassay for carbamazepine with a centrifugal analyzer (Rotochem IIA-36). Reagent costs are reduced fourfold while good precision and sensitivity are maintained. Sample volume is 10 microliter, and as many as 28 patients' sera can be measured during an assay time of 225 s. Assay temperature is 30 degrees C, the wavelength 340 nn. Linearity is excellent for a carbamazepine concentration range of 1 to 12 mg/L; analytical recovery is quantitative. Results correlate well with those by liquid- and gas-liquid chromatography. Absorbance rates for each carbamazepine concentration are acquired by a multi-point kinetic rate program and a computer program provides a logit-log transformation of absorbance rate vs. concentration data for final calculations in the assay. Hemoglobin interference precludes analysis of severely hemolyzed specimens.

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Worsening epidemiological situation of carbapenemase-producing Enterobacteriaceae in Europe, assessment by national experts from 37 countries, July 2018

Eurosurveillance ◽

10.2807/1560-7917.es.2019.24.9.1900123 ◽

2019 ◽

Vol 24 (9) ◽

Cited By ~ 29

Author(s):

Alma Brolund ◽

Nina Lagerqvist ◽

Sara Byfors ◽

Marc J Struelens ◽

Dominique L Monnet ◽

...

Keyword(s):

European Countries ◽

Reference Laboratory ◽

Epidemiological Situation

A survey on the epidemiological situation, surveillance and containment activities for carbapenemase-producing Enterobacteriaceae (CPE) was conducted in European countries in 2018. All 37 participating countries reported CPE cases. Since 2015, the epidemiological stage of CPE expansion has increased in 11 countries. Reference laboratory capability, dedicated surveillance and a specific national containment plan are in existence in 33, 27 and 14 countries, respectively. Enhanced control efforts are needed for CPE containment in Europe.

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Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.

Clinical Chemistry ◽

10.1093/clinchem/22.6.749a ◽

1976 ◽

Vol 22 (6) ◽

pp. 749-753

Author(s):

V Spiehler ◽

L Sun ◽

D S Miyada ◽

S G Sarandis ◽

E R Walwick ◽

...

Keyword(s):

Liquid Chromatography ◽

Enzyme Immunoassay ◽

Correlation Coefficients ◽

Gas Liquid Chromatography ◽

Ultraviolet Spectrophotometry ◽

Epileptic Patients ◽

Quantitative Results ◽

Analytical Procedures

Abstract Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

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Clinical Specificity of the Enzyme Immunoassay Test for Coccidioidomycosis Varies According to the Reason for Its Performance

Clinical and Vaccine Immunology ◽

10.1128/cvi.00531-12 ◽

2012 ◽

Vol 20 (1) ◽

pp. 95-98 ◽

Cited By ~ 28

Author(s):

Janis E. Blair ◽

Neil Mendoza ◽

Shannon Force ◽

Yu-Hui H. Chang ◽

Thomas E. Grys

Keyword(s):

Enzyme Immunoassay ◽

Positive Culture ◽

Clinical History ◽

Immunoglobulin M ◽

Reference Laboratory ◽

Test Results ◽

Radiographic Findings ◽

Asymptomatic Patients ◽

Record Review

ABSTRACTThe diagnosis of coccidioidomycosis relies heavily on serologic test results in addition to clinical history, physical examination, and radiographic findings. Use of the enzyme immunoassay (EIA) has increased because it is rapidly performed and does not require referral to a reference laboratory, as do complement fixation and immunodiffusion tests. However, interpretation of immunoglobulin M (IgM) reactivity by EIA in the absence of immunoglobulin G (IgG) reactivity has been problematic. We conducted a retrospective medical record review of all patients with such IgM reactivity at our institution to identify situations where the finding was more likely to be clinically specific for coccidioidal infection. From 1 January 2004 through 31 December 2008, a total of 1,117 patients had positive EIA coccidioidal serology or EIA IgM-only reactivity; of these, 102 patients (9%) had EIA IgM-only reactivity. Among the 102 patients with EIA IgM-only reactivity, 60 were tested to evaluate symptomatic illness, 13 for follow-up of previously abnormal serology, and 29 for screening purposes. Of the 102 patients, 80 (78%) had positive serologic findings by other methods or had positive culture or histology. Fifty-four (90%) of the 60 patients whose serology was performed to evaluate symptomatic illness had coccidioidal infection, whereas 13 (45%) of 29 patients whose serology was performed for screening purposes had coccidioidal infection. Of the 102 patients with isolated IgM reactivity by EIA, 12 later seroconverted to IgG and IgM reactivity. The use of EIA for screening in 29 asymptomatic persons was associated with unconfirmable results in 13 (45%). Although the majority of patients in our study with isolated IgM reactivity by EIA had probable or confirmed coccidioidomycosis, this result must be interpreted with caution for asymptomatic patients.

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The seroepidemiology of pertussis in Australia during an epidemic period

Epidemiology and Infection ◽

10.1017/s095026880600625x ◽

2006 ◽

Vol 134 (6) ◽

pp. 1208-1216 ◽

Cited By ~ 21

Author(s):

M. CAGNEY ◽

C. R. MacINTYRE ◽

P. McINTYRE ◽

M. PUECH ◽

A. GIAMMANCO

Keyword(s):

European Countries ◽

Enzyme Linked Immunosorbent Assay ◽

Reference Laboratory ◽

Age Group ◽

Notification Rate ◽

Recent Infection ◽

Pertussis Infection ◽

Similar Time ◽

Epidemic Period ◽

The Impact

Studying the epidemiology of pertussis and impact of differing vaccine schedules is difficult because of differing methods of case ascertainment. The advent of internationally standardized serological diagnosis for recent infection has allowed comparison of age-specific pertussis infection among European countries and was applied in Australia at the time of a major national epidemic. In 1997 and 1998, a nationally representative serum bank using residual sera from diagnostic laboratories was established. Measurement of pertussis toxin (PT) IgG level was conducted by a reference laboratory using an enzyme-linked immunosorbent assay standardized for a number of European countries. A titre of 125 EU/ml was interpreted as indicative of recent pertussis infection. The serological data were correlated with age, gender, region and disease epidemiology in Australia. The highest prevalence of recent pertussis infection was in the 5–9 years age group, and the lowest in 1–4 and 25–64 years age groups. In the 5–14 years age group, 29·7% (5–9 years) and 14·6% (10–14 years) of the sample had serological evidence of recent infection, correlating with the pattern of epidemic notifications. The 15- to 24-year-olds had similar high titres but the same notification rate as 25- to 44-year-olds, suggesting ascertainment bias may result in under-notification in the former age group. The prevalence of high titres observed was up to 20-fold higher than some European countries during a similar time period. Although vaccination has reduced the transmission of pertussis in the youngest and most vulnerable age group, pertussis is still endemic in Australia, particularly in older children and the elderly. The Australian vaccination schedule has been changed in an attempt to address this problem, by spacing doses more widely, with the fifth dose at 15–17 years of age. Seroepidemiology for pertussis offers the potential to compare patterns of pertussis between countries and examine the impact of vaccine schedule changes independent of notification and diagnostic bias.

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Radioimmunoassay and enzyme immunoassay compared for determination of digoxin.

Clinical Chemistry ◽

10.1093/clinchem/22.12.2029 ◽

1976 ◽

Vol 22 (12) ◽

pp. 2029-2031 ◽

Cited By ~ 16

Author(s):

L Sun ◽

V Spiehler

Keyword(s):

Enzyme Immunoassay ◽

Correlation Coefficients ◽

Coefficients Of Variation ◽

Quantitative Results ◽

High Control

Abstract Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision (10 days) on a low control (1.3 mug/liter) and a high control 3.0 mg/liter), expressed as coefficients of variation, were: I, 13% and 7.8%, II, 4.0% and 4.7%; and III, 8.9% and 4.2%. Ten digoxin-supplemented samples (0-8 mug/liter) were analyzed by the three methods. Correlation coefficients were: supplemented sample vs. I, O.99; supplemented sample vs. II, 0.97; supplemented sample vs. III, 0.98.

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Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.

Clinical Chemistry ◽

10.1093/clinchem/22.6.749 ◽

1976 ◽

Vol 22 (6) ◽

pp. 749-753 ◽

Cited By ~ 28

Author(s):

V Spiehler ◽

L Sun ◽

D S Miyada ◽

S G Sarandis ◽

E R Walwick ◽

...

Keyword(s):

Liquid Chromatography ◽

Enzyme Immunoassay ◽

Correlation Coefficients ◽

Gas Liquid Chromatography ◽

Ultraviolet Spectrophotometry ◽

Epileptic Patients ◽

Quantitative Results ◽

Analytical Procedures

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Performance of a Cytomegalovirus IgG Enzyme Immunoassay Kit Modified To Measure Avidity

Clinical and Vaccine Immunology ◽

10.1128/cvi.00105-14 ◽

2014 ◽

Vol 21 (6) ◽

pp. 808-812 ◽

Cited By ~ 5

Author(s):

Harry E. Prince ◽

Mary Lapé-Nixon ◽

Susan M. Novak-Weekley

Keyword(s):

Enzyme Immunoassay ◽

Package Insert ◽

Reference Laboratory ◽

High Avidity ◽

Serum Samples ◽

Detection Rates ◽

Igg Avidity ◽

Chemiluminescent Immunoassay ◽

Evaluation Panel ◽

Definition Of

ABSTRACTThe measurement of cytomegalovirus (CMV) IgG avidity accurately discriminates recent and past CMV infections. We sought to determine if the Wampole Laboratories CMV IgG enzyme immunoassay (EIA) could be modified to measure avidity. The evaluation panel consisted of 156 serum samples we used in 2002 to validate a laboratory-developed EIA, in which 78 serum samples exhibited low avidity, 7 exhibited intermediate avidity, and 71 exhibited high avidity. The qualitative agreement between the two avidity assays was 94% (147/156); all 9 sera with discordant results exhibited intermediate avidity in one of the assays. The avidity index (AI) values in the two assays showed excellent correlation (r= 0.96,P< 0.0001). The definition of high avidity was verified for the Wampole assay by demonstrating high avidity in 91/93 (98%) recently collected CMV IgG-positive/IgM-negative serum samples. The performance of the Wampole avidity assay in a reference laboratory setting was assessed using 470 consecutive serum samples submitted for CMV IgG avidity testing. Surprisingly, 101 serum samples were negative when screened for CMV IgG using the Wampole kit per the package insert; 98 of these 101 serum samples were tested using a CMV IgG chemiluminescent immunoassay, and only 5 were positive. Of the 369 CMV IgG-positive samples, 6% exhibited low IgG avidity, 6% exhibited intermediate avidity, and 88% exhibited high avidity; CMV IgM detection rates were inversely related to AI levels. These findings show that (i) the Wampole CMV IgG EIA can be modified to measure CMV IgG avidity, (ii) many samples are apparently submitted for avidity testing without knowledge of their CMV IgG status, and (iii) most CMV IgG-positive sera submitted for avidity testing exhibit high avidity.

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Quantitation of Immunoglobulin to Hepatitis E Virus by Enzyme Immunoassay

Clinical and Vaccine Immunology ◽

10.1128/cdli.9.3.639-648.2002 ◽

2002 ◽

Vol 9 (3) ◽

pp. 639-648 ◽

Cited By ~ 6

Author(s):

Bruce L. Innis ◽

Jitvimol Seriwatana ◽

Robin A. Robinson ◽

Mrigendra P. Shrestha ◽

Patrice O. Yarbough ◽

...

Keyword(s):

Enzyme Immunoassay ◽

Western Blotting ◽

Hepatitis E Virus ◽

Geometric Mean ◽

Hepatitis E ◽

World Health ◽

Confirmatory Test ◽

Reference Laboratory ◽

Operating Characteristics ◽

True Negative

ABSTRACT We developed a quantitative enzyme immunoassay (EIA) for antibody to hepatitis E virus (HEV) by using truncated HEV capsid protein expressed in the baculovirus system to improve seroepidemiology, to contribute to hepatitis E diagnosis, and to enable vaccine evaluations. Five antigen lots were characterized; we used a reference antiserum to standardize antigen potency. We defined Walter Reed antibody units (WR U) with a reference antiserum by using the four-parameter logistic model, established other reference pools as assay standards, and determined the conversion factor: 1 WR U/ml = 0.125 World Health Organization unit (WHO U) per ml. The EIA performed consistently; median intra- and intertest coefficients of variation were 9 and 12%, respectively. The accurate minimum detection limit with serum diluted 1:1,000 was 5.6 WR U/ml; the test could detect reliably a fourfold antibody change. In six people followed from health to onset of hepatitis E, the geometric mean antibody level rose from 7.1 WR U/ml to 1,924.6 WR U/ml. We used the presence of 56- and 180-kDa bands by Western blotting as a confirmatory test and to define true-negative and -positive serum specimens. A receiver-operating characteristics plot identified 30 WR U/ml as an optimum cut-point (sensitivity, 86%; specificity, 89%). The EIA detected antibody more sensitively than a commercially available test. The EIA was transferred to another laboratory, where four operators matched reference laboratory results for a panel of unknowns. Quantitation of antibody to HEV and confirmation of its specificity by Western blotting make HEV serology more meaningful.

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