[Specificity, sensitivity and reproducibility of 2 methods of determining serum immunocomplexes (solid-phase C1q and polyethylene glycol precipitation)].

In the last years a few tests for the detection of circulating immune complexes (CIC) have been published. Nevertheless the data concerning their sensitivity and reproductibility are often partial. The Authors have here analysed, following this point of view, two methods for the detection of CIC, based on different mechanisms and therefore able to identify different kinds of CIC; the tests are: the PEG precipitation test and the C1q solid phase method. The reproductibility of the two methods is good, even when the samples have been many times thawn or kept at 20 degrees C for a few weeks; C1q test sensibility appears distinctly better than PEG test sensibility. By the two methods, but particularly with the PEG, it is possible to identify fluctuation of the IC levels during the day. The contemporaneous use of these two techniques can give results really useful to clinically monitorize some immune complexes diseases, such as many human glomerulonephrites.