(PB), Volume (V), Volume/kg (flow), and Total Bicarbonate Output (TBO) on each patient. Questions: During SST, do V, flow, and TBO of pancreatic juice adequately predict CP as well as the PB? What level of V, flow, or TBO reliably discriminates CP from non-CP? Results: 43.2 % of patients had CP by peak bicarbonate criteria (PB<80mEq/L). Of those, the sensitivity for CP using flow was only 14%. The percent of non-CP patients, ie false positives, with low flow was still 2.7%. The sensitivity for CP using TBO was only 47.4%. TBO was low in 5.3% of non-CP (specificity of 94.7%). Using the Wilcoxon signed rank sum test, the following were observed: (1) Mean V: non-CP (281ml ± 107) vs CP patients (207ml ± 115) p<0.0001. (2) Mean flow: non-CP (4.0ml/kg ± 1.3) vs CP patients (2.8ml/ kg ± 1.3) p<0.0001. (3)Mean TBO: non-CP (23 mEq/hr ± 8.7) vs CP patients (11 mEq/hr ± 7.1) p<0.0001. Using the Spearman linear correlation test, considering all patients, the following observations were made (coefficients in parentheses and all p-values <0.0001): (1) V correlates with PB (0.3537) (2) Flow and especially TBO were more strongly correlated with PB (0.4070 and 0.6571, respectively). Receiver operating curves were made for V, flow, and TBO to see if each could predict the presence of CP. The AUC's were 0.721, 0.769, and 0.867, respectively. Conclusions: Volume and flow correlate linearly with peak bicarbonate concentration during SST but not as well as total bicarbonate output, and a large drop in volume, flow, or total bicarbonate output is required to bring a patient into the PB<80 mEq/L category. Volume and flow do predict the presence of advanced CP but are very insensitive and bicarbonate output is only a somewhat better predictor. Based on data from the secretin stimulation test, S-MRCP's use of volume will miss a significant portion of patients with early CP, particularly those with small duct disease.