Tu1222 A Low CEA Cut-off Identifies Mucinous Pancreatic Cystic Lesions With Increased Diagnostic Accuracy

G A A b st ra ct s was used to measure CEA in cyst fluid. Results: Consistent with recent concerns1, the intra-class correlation (ICC) between undiluted cyst fluid CEA measurements and CEA measurements from cyst fluid diluted in UD or saline was only 0.5 (Figure 1). The low ICC was due to significant positive bias in the measurement of CEA in about 1/2 of the cyst fluids that were diluted with UD or saline (Mean bias UD or saline = 0.6, P-values , 0.0001). Similarly, the ICC between undiluted CEA measurements and CEA measurements diluted in RPD was only 0.5. However, about 1/2 RPD diluted fluids had significant negative bias in the measurement of CEA (Mean bias RPD = 2.5, P-value , 0.0001). Based on these observations, we determined cyst fluid biochemical characteristics that could identify fluids that when excluded from the analysis removed the positive and negative bias observed with each respective diluent. When these biochemical characteristics were used to dictate which diluent to implement, the resulting ICC between diluted and undiluted CEA was 0.9 (Figure 1). The use of each diluent based on these biochemical properties removed all significant bias in the CEA measurement (Mean bias saline [or UD] and RPD = 1.3, P-value = 0.4). Conclusions: Cyst fluid dilution can significantly impact the accuracy of CEA measurement. Dilution induced errors in CEA are due to properties of cyst fluid samples. The use of saline (or UD) and RedPath's novel diluent (RPD), based onmeasurable biochemical fluid properties, results in more accurate CEA measurement in diluted pancreatic cyst fluid. References: 1 Boot, C. S., et al. Clinical chemistry 56, 1351-1352, doi:10.1373/clinchem.2010.146373 (2010).