MDx-Chex for BCP

MDx-Chex for BCP is a quality control kit containing positive and negative assayed controls for the DiaSorin LIAISON PLEX Gram-Positive Blood Culture assay. It is used to monitor the performance of the qualitative detection of gram-positive bacteria and associated antimicrobial resistance genes (mecA/mecC, vanA, vanB) on the LIAISON PLEX System. The controls are composed of a buffered solution with stabilized erythrocytes and leukocytes in a matrix of blood culture media components and are not intended to replace manufacturer controls.

MDx-Chex for BCP contains 16 targets (13 gram-positive bacterial species/genera plus 3 antimicrobial resistance genes) compared to the predicate MDx-Chex for BC-GP which contains 15 targets. Both are ready-to-use liquids processed like patient samples and monitor the same assay steps: lysis, nucleic acid isolation/purification/inhibitor removal, DNA hybridization, detection, and identification/data reporting. The candidate device is formulated for the DiaSorin LIAISON PLEX system while the predicate was for the Luminex VERIGENE system.

Not stated in this summary. The document references ISO 13485 and ISO 13484 in the context of Quality Management System Regulation requirements but does not cite specific test method standards or consensus standards for device validation.

Substantial equivalence is established through demonstrated reproducibility across three sites and multiple operators (99% positive agreement, 98% negative agreement), repeatability with ≥90% agreement, lot-to-lot consistency with 100% agreement, stability through 110 days at 2–25°C, shipping stability under summer and winter conditions, and matrix effect studies showing identical performance to clinical blood culture samples. The device shares the same intended use (external quality control for gram-positive blood culture detection), physical format (ready-to-use liquid), composition principles (stabilized blood components in culture media matrix), and assay step monitoring as the predicate device.