Detecting Exogenous Contamination of Clinical Blood Samples with Crystalloid Solutions: A Data Driven Approach to Derive and Validate Delta Checks

Abstract Pre-analytical error may occur when collecting blood samples from intravenous (IV) lines. Blood can be inadvertently diluted by exogenous solutions if an insufficient amount of is discarded prior to collection. Rules built in the laboratory information system or middleware used alert staff specimens that require co-investigation with clinical team determine sample dilution possible likely. Currently, however, there a lack literature guide laboratorians on how define quality rules this nature, particularly for detecting subtle, rather than gross contamination commonly administered IV-fluids. Accordingly, primary objective study derive sensitive and specific, multivariate delta checks detect more subtle crystalloid solutions. To rules, we began vitro experiments spiking increasing volumes major IV-fluids (normal saline (NS), lactated ringers (LR), 5% dextrose (D5W)) into were collected healthy donors (n=3). Crystalloid serially spiked at 10% (solution:sample) increments NS LR up 90%, D5W, 50%. Basic metabolic panel (BMP) analytes measured compared between neat contrived samples. All testing was performed Roche Cobas 8000 chemistry auto-analyzers. Based data, derived using BMP would reflect 10-40% given fluid. We then retrospective data analysis 28 thousand, results identify flagged these rules. Chart review EHR-based evidence temporally associated administration through peripheral IV access line. Increasing showed significant changes several across all fluid types. With respect NS, most relative baseline observed potassium, calcium, chloride, while LR, glucose, bicarbonate, calcium. For chloride sodium. check implemented aforementioned analytes. On chart review, found 80-100% came patients last 12-24 hours. The support consider multiple analytes, fluid-specific bias profiles, as provide specific approach Further evaluation will validate sensitivity specificity followed prospective before implementation.