PLA2R1 and glioblastoma: We found that the readings of anti-PLA2R antibodies in clear serum samples, turbid serum samples and haemolytic serum samples and the readings of anti-GBM antibodies, anti-MPO antibodies and anti-PR3 antibodies in clear serum samples all increased following incubation at 4 °C for 6 weeks, and the differences were significant (p < 0.001 for anti-PLA2R antibodies in clear serum samples, turbid serum samples and haemolytic serum samples and anti-GBM antibodies and anti-PR3 antibodies in clear serum samples; p < 0.01 for anti-MPO antibodies in clear serum samples).