LAUSR

BACKGROUND Onconeural antibodies are a group of autoantibodies present in patients with paraneoplastic syndromes (PNS), and are indicative for underlying malignancies. The use of indirect immunofluorescence assay (IFA) as the sole screening method for onconeural antibodies without line blot assay (LBA) could potentially miss a significant population of patients with PNS. However, testing each serum individually on LBA will pose significant economical and labour burdens to clinical laboratories. Based on the screening result from IFA, we developed a cost-effective pooling strategy for the detection of onconeural antibodies on LBA. METHODS Results of onconeural antibodies tested by IFA and LBA from 1887 serum samples received in the Central Sydney Immunology Laboratory were retrospectively analysed. Sera were pre-screened by IFA before proceeding to LBA. Sera with positive staining on IFA were tested individually on LBA while sera with negative IFA were examined by pooling. Agreements of antibody reactivity against onconeural antigens were evaluated for sera run by pooling and by individually. The estimate of the cost saving was also conducted for the pooling strategy. RESULTS Antibody reactivity to each specific onconeural antigen from pooling run had over 95% qualitative result agreement with sera run individually on LBA. An excellent correlation (r = 0.88) of positive reactions quantitated by band signal intensity was also observed. Using our well-established sera pooling strategy for LBA, a cost saving of 50.1% was achieved for reagent alone. CONCLUSIONS The sera pooling strategy for LBA is a reliable and cost-effective approach for testing low prevalence diseases such as PNS.