Evaluation of Sebia’s Capillarys 2 flex-piercing system in comparison with Hydrasys gel system, in identifying low level monoclonal protein in serum and urine of patients with suspected multiple myeloma

Background: Challenges exist with the screening and diagnosis of multiple myeloma. These are especially relevant to cases where there are low levels of monoclonal proteins or when the monoclonal band co-migrates with the increased polyclonal immunoglobulin response. We evaluated the new automated CAPILLARYS 2 Flex-Piercing system and its capability to overcome these challenges in early cases of multiple myeloma patients where the diagnosis had been confirmed by bone marrow biopsy. Methods: This was a comparative study using serum and urine specimens sent from patients with suspected monoclonal gammopathy and was conducted using the CAPILLARYS 2 Flex-Piercing fully-automated and the Hydrasys semi-automated systems. Serum and urine protein electrophoresis were evaluated in both systems and where monoclonal bands were suspected or seen, immunofixation/immunotyping was evaluated to confirm the diagnosis. Results: One hundred and sixty-six (166) serum and 49 urine samples were tested, 34 serum and 37 urine samples also had immunofixation and immunotyping done due to the presence of suspicious bands. Concordance in the IFE/IT between the two systems was 96% for serum and 76% for urine analysis. In serum results, the CAPILLARYS 2 Flex-Piercing system showed sensitivity and specificity of 100%, while the Hydrasys gel system had a lower sensitivity of 97.14% and specificity of 99.21%. In contrast Capillary urine results showed 86.49% sensitivity and 50% specificity while Hydrasys displayed 100% sensitivity and specificity. This contributed to the discordance observed between the two systems. In 5 of the 49 urine samples, the gel IFE system identified low level urinary free light chains, which the CAPILLARYS 2 Flex-Piercing system missed. Conclusion: The proposed system is faster, involves less human error and has a better capability in distinguishing monoclonal bands in the background of a polyclonal response. However, in urine protein electrophoresis, the gel IFE system demonstrated an increased sensitivity for the detection of low level free light chains.