A critical evaluation of enzyme immunoassay kits for detection of antinuclear autoantibodies of defined specificities. II. Potential for quantitation of antibody content.
OBJECTIVE
To analyze the performance of different commercial enzyme immunoassay (EIA) kits for measuring antibody levels of antinuclear antibodies (ANA) specific for double stranded (ds) DNA, SSB/La, Sm, and Scl-70.


METHODS
Twenty companies that were known major purveyors of EIA kits for detection of ANA were approached to determine their interest and willingness to participate in this study. The manufacturers were advised that they would be sent coded sera containing mixtures of the Arthritis Foundation/Centers for Disease Control reference reagents, and that they were to use their own test kits to analyze the antibody specificities of these sera and to report the data, in optical density (OD) units, or their equivalent. The analysts were blinded to the concentration of the antibodies and the specificities.


RESULTS
Initially, 11 manufacturers out of 20 agreed to participate, but 2 subsequently withdrew. The commercial EIA kits have the potential of being able to quantitate specific autoantibody content to ds-DNA, SSB/La, Sm, and Scl-70. However, certain deficiencies in these kits were also detected, the most obvious being lack of uniformly good performance, with kits of certain manufacturers showing exceptional accuracy in 3 out of 4 of their antibody-specific kits and poor accuracy for a 4th kit.


CONCLUSIONS
It is important for clinicians to appreciate that there is marked inter-manufacturer variation in the performance of EIA kits used as an aid in the diagnosis of systemic rheumatic diseases. Manufacturers need to exercise constant surveillance of kit performance and to provide assurance that such is being done. Improved EIA kits would lend themselves to reliable quantitation of antibody levels in human sera and help to determine whether serial measurement of antibody levels might be useful in monitoring disease activity.
Tan
Eng M
EM
Autoantibody Standardization Committee in Rheumatic and Related Disorders of the International Union of Immunological Societies, The World Health Organization, The Arthritis Foundation, and Centers for Disease Control and Prevention.
Smolen
Josef S
JS
McDougal
J Steven
JS
Fritzler
Marvin J
MJ
Gordon
Thomas
T
Hardin
John A
JA
Kalden
Joachim R
JR
Lahita
Robert G
RG
Maini
Ravinder N
RN
Reeves
Westley H
WH
Rothfield
Naomi F
NF
Takasaki
Yoshinari
Y
Wiik
Allan
A
Wilson
Merlin
M
Koziol
James A
JA
D000974:Antibodies, Antinuclear / Q000032:analysis* / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis* / Q000097:blood / Q000276:immunology; D001327:Autoimmune Diseases / Q000097:blood* / Q000175:diagnosis / Q000276:immunology*; D004247:DNA / Q000032:analysis / Q000097:blood / Q000276:immunology; D004264:DNA Topoisomerases, Type I; D004268:DNA-Binding Proteins / Q000032:analysis / Q000097:blood / Q000276:immunology; D005069:Evaluation Studies as Topic; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods / Q000592:standards* / Q000639:trends; D009687:Nuclear Proteins / Q000032:analysis / Q000097:blood / Q000276:immunology; D012044:Regression Analysis
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C048100:Scl 70 antigen, human; D004247:DNA; D004264:DNA Topoisomerases, Type I