Comparison of the performance of the LIAISON VZV-IgG and VIDAS automated enzyme linked fluorescent immunoassays with reference to a VZV-IgG time-resolved fluorescence immunoassay and implications of choice of cut-off for LIAISON assay.
BACKGROUND
Determination of Varicella Zoster virus (VZV) immune status in pregnant women without history of chickenpox is important in identifying those who genuinely need VZV immune globulin prophylaxis following significant exposure to chickenpox or shingles. Immune status testing requires highly sensitive and specific immunoassays for timely and accurate results.


OBJECTIVE
To compare the performance of DiaSorin LIAISON and Biomerieux VIDAS VZV-IgG assays with reference to a VZV-IgG time-resolved fluorescence immunoassay (TRFIA).


METHODS
A panel of sera collected from 65 pregnant contacts of VZV and 62 individuals tested for VZV immunity was tested in all three assays. Dose-response curves were generated using International Standards W1044 and 90/690.


RESULTS
Sensitivity and specificity of VIDAS compared to VZV-TRFIA was 54.5% and 97.9% respectively and for LIAISON compared to VZV-TRFIA was 67% and 100% respectively. Both assays correlated well with TRFIA with R2 correlation coefficients of 0.79 and 0.76 respectively. Dose-response curves showed both Standards behaved in a similar manner in each assay. For VIDAS, the test cut-off value of 0.9 correlated with 275-280mIU/ml and for LIAISON a cut-off value of 150mIU/ml correlated with 208-219mIU/ml.


CONCLUSIONS
By dose-response data and in comparison with TRFIA, LIAISON is more sensitive and specific than VIDAS.
Maple
P A C
PA
Virus Reference Department, HPA Centre for Infections, Colindale, London, United Kingdom.
Rathod
P
P
Smit
E
E
Gray
J
J
Brown
D
D
Boxall
E H
EH
D000914:Antibodies, Viral / Q000097:blood*; D002644:Chickenpox / Q000175:diagnosis / Q000517:prevention & control*; D005260:Female; D005453:Fluorescence; D006562:Herpes Zoster / Q000175:diagnosis / Q000517:prevention & control*; D014645:Herpesvirus 3, Human / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood*; D011247:Pregnancy; D012680:Sensitivity and Specificity
D000914:Antibodies, Viral; D007074:Immunoglobulin G