Evaluation of enzyme-linked immunosorbent assays: a method of data analysis

Crofts, Nick; Maskill, William J.; Gust, Ian D.

doi:10.1016/0166-0934(88)90087-0

Cited by 36 publications

(15 citation statements)

References 13 publications

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“…Since it is reported that, when comparing different ELISAs, it is more useful to deal with actual values (OD values or sample OD/cut-off OD ratio) rather than the qualitative relationship to the cut-off, that is, positive or negative [Crofts et al, 1988], the distribution of anti-HEV IgG OD values was shown in Figure 2, which seemed to offer confidence in the assay results. In the previous study using 659 serum samples obtained from HEV unexposed subjects as a panel [Takahashi et al, 2005a and unpublished observations], the cut-off value of the anti-HEV IgG assay was set at 0.175, corresponding to seven SDs above the mean value (0.018).…”

Section: Discussionmentioning

confidence: 99%

A nationwide survey of hepatitis E virus infection in the general population of Japan

Takahashi

Tamura

Hoshino

et al. 2009

Journal of Medical Virology

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To investigate nationwide the prevalence of hepatitis E virus (HEV) infection in the general population of Japan, serum samples were collected from 22,027 individuals (9,686 males and 12,341 females; age, mean +/- standard deviation: 56.8 +/- 16.7 years; range: 20-108 years) who lived in 30 prefectures located in Hokkaido, mainland Honshu, Shikoku, and Kyushu of Japan and underwent health check-ups during 2002-2007, and were tested for the presence of IgG, IgM, and IgA classes of antibodies to HEV (anti-HEV) by in-house ELISA and HEV RNA by nested RT-PCR. Overall, 1,167 individuals (5.3%) were positive for anti-HEV IgG, including 753 males (7.8%) and 414 females (3.4%), the difference being statistically significant (P < 0.0001). The prevalence of anti-HEV IgG generally increased with age and was significantly higher among individuals aged >or=50 years than among those aged <50 years (6.6% vs. 2.7%, P < 0.0001). Although 13 individuals with anti-HEV IgG also had anti-HEV IgM and/or anti-HEV IgA, none of them had detectable HEV RNA. The presence of HEV RNA was further tested in 50 or 49-sample minipools of sera from the remaining 22,014 individuals, and three individuals without anti-HEV antibodies tested positive for HEV RNA. The HEV isolates obtained from the three viremic individuals segregated into genotype 3 and were closest to Japan-indigenous HEV strains. When stratified by geographic region, the prevalence of anti-HEV IgG as well as the prevalence of HEV RNA or anti-HEV IgM and/or anti-HEV IgA was significantly higher in northern Japan than in southern Japan (6.7% vs. 3.2%, P < 0.0001; 0.11% vs. 0.01%, P = 0.0056; respectively).

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Section: Discussionmentioning

confidence: 99%

A nationwide survey of hepatitis E virus infection in the general population of Japan

Takahashi

Tamura

Hoshino

et al. 2009

Journal of Medical Virology

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“…For evaluating the probability of false positivity of the assay, a negative d value was calculated as logarithmic population means of signal to cutoff ratios divided by the logarithmic standard deviation of the signal to cutoff ratios [11]. The results for the women who showed grey zone reactivity on CMV IgM were not used for calculating the negative d value, because these women were treated as seropositive in this study.…”

Section: Discussionmentioning

confidence: 99%

Serologic Screening of Pregnant Korean Women for Primary Human Cytomegalovirus Infection Using IgG Avidity Test

2009

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“…A P value of Ͻ0.05 was considered statistically significant. Positive and negative delta values were estimated for each immunoassay (5). The delta value is the distance the mean of the positive and negative populations of a data set is removed from the cutoff and is measured in standard deviations.…”

Section: Samplesmentioning

confidence: 99%

Evaluation of Eight Anti-Rubella Virus Immunoglobulin G Immunoassays That Report Results in International Units per Milliliter

et al. 2008

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An evaluation of anti-rubella virus immunoglobulin G (IgG) immunoassays that report in international units per milliliter (IU/ml) was performed to determine their analytical performance and the degree of correlation of the test results. A total of 321 samples were characterized based on results from a hemagglutination inhibition assay. The 48 negative and 273 positive samples were used to determine the sensitivity and specificity of the assays. When equivocal results were interpreted as reactive, the sensitivity of the immunoassays ranged from 98.9 to 99.9% and the specificity ranged from 77.1 to 95.8%. All assays had positive and negative delta values of less than 2. A significant difference between the mean results of all assays was demonstrated by analysis of variance. However, post hoc analysis showed there was good correlation in the mean results expressed in IU/ml between some of the assays. Our results show the level of standardization between anti-rubella virus IgG immunoassays reporting results expressed as IU/ml has improved since a previous study in 1992, but further improvement is required.Rubella virus causes a relatively benign childhood rash and fever. However, primary maternal infection during the first trimester is associated with a 80 to 90% risk of congenital rubella syndrome (2,3,25). In developed countries, the risk of congenital rubella syndrome has been minimized through vaccination programs (22-24) and by testing pregnant women for evidence of rubella virus immunoglobulin G (IgG) at their first antenatal visit (10, 11). Since the isolation of rubella virus in 1962, rubella testing has developed continuously, with the hemagglutination inhibition (HAI) assay often being considered the reference method (4,15,29).Since the 1980s, rubella virus IgG assays have been calibrated against the same World Health Organization (WHO) international standard rubella virus serum (second standard preparation) and test results have been reported in international units per milliliter (IU/ml). The introduction of quantitative measurement of rubella virus IgG had the potential to increase standardization and facilitate the comparison between the results of different tests.In 1992, we published a multicenter evaluation comparing commercial immunoassays used to measure rubella virus IgG antibodies (9). The conclusion was that, although there was a moderate degree of correlation, reporting anti-rubella virus IgG levels in IU/ml had insufficient practical use. At that time, we concluded that the results of rubella virus antibody testing be confined to a statement concerning immunity rather than a numerical value. More than 15 years later, the assays compared in the 1992 study are no longer in common usage in Australia and have generally been replaced with random-access analyzers that perform a range of immunoassays of multiple disciplines. A comparison of six random-access and two microtiter plate (MTP) immunoassays that report anti-rubella virus IgG levels in IU/ml was undertaken to review analytical performance a...

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Evaluation of enzyme-linked immunosorbent assays: a method of data analysis

Cited by 36 publications

References 13 publications

A nationwide survey of hepatitis E virus infection in the general population of Japan

A nationwide survey of hepatitis E virus infection in the general population of Japan

Serologic Screening of Pregnant Korean Women for Primary Human Cytomegalovirus Infection Using IgG Avidity Test

Evaluation of Eight Anti-Rubella Virus Immunoglobulin G Immunoassays That Report Results in International Units per Milliliter

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