Objective:

To determine if the serology increases the validity of the clinical and Echo as a predictor of acute obstruction of the main bile duct (OAVBP) and to determine if by stopping considering them it is possible to reduce unnecessary ERCP.

Materials and Methods:

It is a retrospective analysis of diagnostic tests carried out in a third level private hospital. 182 stories were analyzed.

The validity as a predictor of OAVBP was determined for:

clinical (jaundice, Charcot's triad) Echo (7mm common bile duct and foreign body) and serology (FA, GGT, AST, ALT and bilirubin). The influence of the primary diagnosis, the Eco-ERCP time, previous cholecystectomy, age and fluctuation in serology were investigated. A three-level scale based on probability indices (LR), (null, low and high) was used for different cut points of serology and common bile duct diameter. The repercussions of not considering serology as a predictor of OAVBP were included, including direct hospital costs.

Results:

The type of diagnosis influenced the validity of the tests. Echo was the only useful test in patients with acute pancreatitis with a sensitivity of 90-100%. In other diagnoses, jaundice (S: 72 E: 59) and dilated common bile duct were the best (S: 69 E: 52). GGT and ALT were the most sensitive enzymes, but their PPV was null. AF and bilirubins improved the PPV and NPV of jaundice and Echo only when a high probability cut-off point was used. Serology did not increase the sensitivity of jaundice and / or echo. Neither did unnecessary ERCP decrease when they were no longer considered. An 8mm common bile duct measured by Eco showed higher / PP without decreasing sensitivity.

Conclusion:

Serology has no utility in the screening of OAVBP since it does not increase the sensitivity of the clinic and / or Echo. However, it increases the PPV and NPV if a simple mathematical model is used. Not considering it does not reduce unnecessary ERCP.