4.5. PEG precipitation assay

In this assay, the same principle of the Farr assay is applied where a solution of radiolabeled DNA is used as the test antigen for anti-DNA antibodies in the serum sample. However, instead of using ammonium sulfate for precipitation, polyethylene glycol is used as the precipitating agent, which mainly leads to the recovery of low-affinity anti-DNA antibodies in contrast to the Farr assay [110].
