The differentiation of cholesterol and pigment gallstones

Gallbladder biles and stones were obtained at 116 cholecystectomies
for symptomatic gallstone disease. All 33 patients younger than 50
years had cholesterol stones, whereas 40% of the older patients had
pigment stones. We compared the reliability of three different bile
tests for the differentiation between cholesterol and pigment stone
patients. Whereas both the presence of cholesterol monohydrate
crystals in fresh gallbladder bile and a nucleation time 20 days in
ultrafiltered gallbladder bile had a specificity of 100% for
cholesterol gallstone disease, biliary supersaturation with
cholesterol (cholesterol saturation index >1.0) had a low
specificity. The sensitivity of nucleation time 20 days for
cholesterol gallstone disease was 78% in concentrated gallbladder
biles (biliary total lipid concentration 5 g/dl) but only 21% in
dilute biles (biliary total lipid concentration