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Precision of the Kalon Herpes Simplex Virus Type 2 IgG ELISA: an international inter-laboratory assessment.

Patel EU, Manucci J, Kahle EM, Lingappa JR, Morrow RA, Piwowar-Manning E, James A, Maluzi KF, Cheeba MM, Gray G, Delany-Moretlwe S, Inambao M, Vwalika B, Quinn TC, Laeyendecker O - BMC Infect. Dis. (2015)

Bottom Line: Intra-assay, intra-laboratory, and inter-laboratory correlation and agreement were significantly high (p < 0.01).Accordingly, operator errorlikely does not contribute to the variability observed in Kalon's specificity throughout sera from sub-Saharan Africa.In populations with optimal diagnostic accuracy, Kalon is a reliable stand-alone method for on-site HSV-2 IgG antibody detection.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunoregulation, Division of Intramural Research, NIAID, NIH, Baltimore, MD, USA. epatel6@jhmi.edu.

ABSTRACT

Background: The commercial Kalon HSV-2 IgG ELISA is currently recommended for research use in sub-Saharan Africa because of its superior accuracy compared to other serologic assays. However, there are no data on key precision parameters of Kalon such as inter-operator variation, repeatability, and reproducibility, thus contributing to a barrier for its acceptance and use in clinical trials in sub-Saharan Africa. We evaluated the analytical and field precision of the Kalon HSV-2 IgG ELISA.

Methods: A total of 600 HIV-infected and uninfected serum samples from South Africa and Zambia, previously tested by the gold standard University of Washington HSV western blot (UW-WB), were tested using Kalon by two technologists in an United States reference laboratory. Aliquots of 183 samples were retested using Kalon by an on-site technologist in a South African laboratory and a Zambian laboratory.

Results: Intra-assay variation was below 10 %. Intra-assay, intra-laboratory, and inter-laboratory correlation and agreement were significantly high (p < 0.01). In comparison to the UW-WB, accurate performance of Kalon was reproducible by each operator and laboratory. Receiver operating characteristic curve analysis indicated high selectivity of Kalon in the overall study population (area under the curve = 0.95, 95%CI = 0.92-0.97).

Discussion: Kalon is a robust assay with high precision and reproducibility. Accordingly, operator errorlikely does not contribute to the variability observed in Kalon's specificity throughout sera from sub-Saharan Africa.

Conclusions: In populations with optimal diagnostic accuracy, Kalon is a reliable stand-alone method for on-site HSV-2 IgG antibody detection.

No MeSH data available.


Related in: MedlinePlus

The field precision of the Kalon HSV-2 IgG ELISA. a Shows box plots that represent the range, interquartile range, and median Kalon index values for samples tested by all operators (n = 170). The star and pound signs represent inter-operator comparisons by the Wilcoxon rank-sum test. b Shows the correlation and variability in Kalon index values between operators and also presents the agreement of categorical results between operators as determined by the manufacturer’s index cut-offs (<0.9, negative; 0.9–1.1, indeterminate; >1.1 positive); (n = 170). c Depicts any sample that had a Kalon result that was discordant from other Kalon results by all operators (n = 183). The a indicates that these results were generated by Technologist-Sr. in South Africa
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Fig3: The field precision of the Kalon HSV-2 IgG ELISA. a Shows box plots that represent the range, interquartile range, and median Kalon index values for samples tested by all operators (n = 170). The star and pound signs represent inter-operator comparisons by the Wilcoxon rank-sum test. b Shows the correlation and variability in Kalon index values between operators and also presents the agreement of categorical results between operators as determined by the manufacturer’s index cut-offs (<0.9, negative; 0.9–1.1, indeterminate; >1.1 positive); (n = 170). c Depicts any sample that had a Kalon result that was discordant from other Kalon results by all operators (n = 183). The a indicates that these results were generated by Technologist-Sr. in South Africa

Mentions: The mean calibrator OD units were significantly higher in the Zambian and South African laboratory sites compared to performance at the HPTN Laboratory Center (Fig. 2). Of the 183 samples tested by all operators, 13 samples had an OD > 3.0 in the HPTN Laboratory Center and were excluded from continuous comparisons. The mean Kalon index value was significantly higher at the HPTN Laboratory Center (mean index: 2.87) compared to the South African laboratory site (mean index = 1.68) and Zambian laboratory site (mean index = 1.72; P < 0.01). The differences in the mean index value between the South African and Zambian laboratories were not significant (P = 0.921). Fig. 3a depicts the range of Kalon index values for all operators (n = 170). Inter-laboratory variation was higher than intra-laboratory variation, with the CV ranging from 30.5 to 46.1 % (n = 170; Fig. 3b).Fig. 2


Precision of the Kalon Herpes Simplex Virus Type 2 IgG ELISA: an international inter-laboratory assessment.

Patel EU, Manucci J, Kahle EM, Lingappa JR, Morrow RA, Piwowar-Manning E, James A, Maluzi KF, Cheeba MM, Gray G, Delany-Moretlwe S, Inambao M, Vwalika B, Quinn TC, Laeyendecker O - BMC Infect. Dis. (2015)

The field precision of the Kalon HSV-2 IgG ELISA. a Shows box plots that represent the range, interquartile range, and median Kalon index values for samples tested by all operators (n = 170). The star and pound signs represent inter-operator comparisons by the Wilcoxon rank-sum test. b Shows the correlation and variability in Kalon index values between operators and also presents the agreement of categorical results between operators as determined by the manufacturer’s index cut-offs (<0.9, negative; 0.9–1.1, indeterminate; >1.1 positive); (n = 170). c Depicts any sample that had a Kalon result that was discordant from other Kalon results by all operators (n = 183). The a indicates that these results were generated by Technologist-Sr. in South Africa
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4591065&req=5

Fig3: The field precision of the Kalon HSV-2 IgG ELISA. a Shows box plots that represent the range, interquartile range, and median Kalon index values for samples tested by all operators (n = 170). The star and pound signs represent inter-operator comparisons by the Wilcoxon rank-sum test. b Shows the correlation and variability in Kalon index values between operators and also presents the agreement of categorical results between operators as determined by the manufacturer’s index cut-offs (<0.9, negative; 0.9–1.1, indeterminate; >1.1 positive); (n = 170). c Depicts any sample that had a Kalon result that was discordant from other Kalon results by all operators (n = 183). The a indicates that these results were generated by Technologist-Sr. in South Africa
Mentions: The mean calibrator OD units were significantly higher in the Zambian and South African laboratory sites compared to performance at the HPTN Laboratory Center (Fig. 2). Of the 183 samples tested by all operators, 13 samples had an OD > 3.0 in the HPTN Laboratory Center and were excluded from continuous comparisons. The mean Kalon index value was significantly higher at the HPTN Laboratory Center (mean index: 2.87) compared to the South African laboratory site (mean index = 1.68) and Zambian laboratory site (mean index = 1.72; P < 0.01). The differences in the mean index value between the South African and Zambian laboratories were not significant (P = 0.921). Fig. 3a depicts the range of Kalon index values for all operators (n = 170). Inter-laboratory variation was higher than intra-laboratory variation, with the CV ranging from 30.5 to 46.1 % (n = 170; Fig. 3b).Fig. 2

Bottom Line: Intra-assay, intra-laboratory, and inter-laboratory correlation and agreement were significantly high (p < 0.01).Accordingly, operator errorlikely does not contribute to the variability observed in Kalon's specificity throughout sera from sub-Saharan Africa.In populations with optimal diagnostic accuracy, Kalon is a reliable stand-alone method for on-site HSV-2 IgG antibody detection.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunoregulation, Division of Intramural Research, NIAID, NIH, Baltimore, MD, USA. epatel6@jhmi.edu.

ABSTRACT

Background: The commercial Kalon HSV-2 IgG ELISA is currently recommended for research use in sub-Saharan Africa because of its superior accuracy compared to other serologic assays. However, there are no data on key precision parameters of Kalon such as inter-operator variation, repeatability, and reproducibility, thus contributing to a barrier for its acceptance and use in clinical trials in sub-Saharan Africa. We evaluated the analytical and field precision of the Kalon HSV-2 IgG ELISA.

Methods: A total of 600 HIV-infected and uninfected serum samples from South Africa and Zambia, previously tested by the gold standard University of Washington HSV western blot (UW-WB), were tested using Kalon by two technologists in an United States reference laboratory. Aliquots of 183 samples were retested using Kalon by an on-site technologist in a South African laboratory and a Zambian laboratory.

Results: Intra-assay variation was below 10 %. Intra-assay, intra-laboratory, and inter-laboratory correlation and agreement were significantly high (p < 0.01). In comparison to the UW-WB, accurate performance of Kalon was reproducible by each operator and laboratory. Receiver operating characteristic curve analysis indicated high selectivity of Kalon in the overall study population (area under the curve = 0.95, 95%CI = 0.92-0.97).

Discussion: Kalon is a robust assay with high precision and reproducibility. Accordingly, operator errorlikely does not contribute to the variability observed in Kalon's specificity throughout sera from sub-Saharan Africa.

Conclusions: In populations with optimal diagnostic accuracy, Kalon is a reliable stand-alone method for on-site HSV-2 IgG antibody detection.

No MeSH data available.


Related in: MedlinePlus