Establishing "normal" values for liver function tests after reconstruction of biliary injuries

Area of Science:

• Hepatology
• Surgical Gastroenterology
• Clinical Biochemistry

Background:

• Liver function tests (LFTs) are often used to assess outcomes after biliary injury repair.
• Elevated LFTs may be misinterpreted as complications rather than normal variations.

Purpose of the Study:

• To establish reference LFT values in patients with excellent outcomes (>6 months post-repair) after biliary-enteric anastomosis for biliary injury.
• To differentiate normal LFT variations from actual liver or anastomotic dysfunction.

Main Methods:

• Retrospective analysis of 73 patients who underwent biliary injury repair and had LFTs available at >6 months post-surgery.
• Standardization of external LFT results to Barnes-Jewish Hospital values.
• Collection of one LFT set per patient at 6 months-2 years, 2-5 years, and >5 years post-repair.

Main Results:

• The 97.5th percentile for alkaline phosphatase was >= 166 IU/L and for total bilirubin was >= 1.3 mg/dL, exceeding standard reference values.
• Alanine aminotransferase and aspartate aminotransferase values showed greater variability.
• These elevated values were observed in patients with excellent postoperative courses.

Conclusions:

• Moderate LFT elevations are common and can be considered normal after successful biliary injury repair.
• Alkaline phosphatase levels tend to decrease over time post-repair.
• LFTs below the established 97.5th percentile limits should not be interpreted as signs of liver or anastomotic dysfunction.