Author/Editor		Čučnik, Saša; Ambrožič, Aleš; Božič, Borut; Skitek, Milan; Kveder, Tanja
Title		Anti-beta2-glycoprotein I ELISA: methodology, determination of cut-off values in 434 healthy Caucasians and evaluation of monoclonal antibodies as possible international standards
Type		članek
Source		Clin Chem Lab Med
Vol. and No.		Letnik 38, št. 8
Publication year		2000
Volume		str. 777-83
Language		eng
Abstract		Antibodies against beta2-glycoprotein I are among the most commonly detected subset of antiphospholipid antibodies. The inter-laboratory comparability of results is hardly possible due to methodological differences, lack of international standards and different cut-off values. We evaluated and ELISA for the detection of anti-beta2-glycoprotein I using the analytical goals based on biological variations for similar analytes (immunoglobulins). By our ELISA we fulfield the optimal (IgA, IgM) or minimal (IgG) analytical goals in long-term imprecision. The determination of cut-off values was based on the frequency distribution of results obtained on 434 healthy Caucasians. To aim at a better inter-laboratory comparability we tested two monoclonal antibodies as possible calibrators: HCAL (gG) and EY2C9 (IgM). Binding properties determined by dilutional curves showed great similarities with polyclonal sera, used as in-house standards. Cutt-off values were expressed by concentrations of IgG and IgM monoclonal antibodies (4.5 and 25.3 microg/l). Our study shows the possibility for a successful application of analytical goals based on biological variation even when data for a particular analyte are not available. The expression of cut-off values, obtained on a large scale Caucasian population, by the concentration of IgG and IgM monoclobal antibodies could make possible a more reliable inter-laboratory comparison of data.
Descriptors		ANTIBODIES, ANTIPHOSPHOLIPID AUTOANTIBODIES ANTIBODIES, MONOCLONAL ENZYME-LINKED IMMUNOSORBENT ASSAY IGG IGM IGA