Dear all
 
We currently use the Diazyme Total Bile Acids assay in our lab to measure BAs on those with Obstetric Cholestasis (and we are now getting samples from gastro patients, too). The assay is enzymatic (using the enzyme 3-alpha-hydroxysteroid dehydrogenase to convert bile acids to 3-keto steroids and Thio-NAD to Thio-NADH) and absorbance is measured at 405 nm.
 
In the kit insert it states that specimens from patients who are on Ursodeoxycholic Acid (UDCA) are not suitable for this assay (I'm assuming this is due to positive interference in the assay-data from WEQAS show this assay has a 56% recovery of UDCA). Obviously, we have a number of patients who are being treated with UDCA and who are wanting to be monitored using the Total Bile Acid concentration. I haven't had much luck in getting hold of Diazyme to find out more details so I was wondering if anyone out there could share with me how they deal with samples from patients on UDCA who require Total Bile Acid analysis.
 
We are also evaluating our current reference range for Total Bile Acids (originally from Selly Oak I believe: 0-6 umol/L). I would be very grateful if you are currently using the Enzymatic Thio-NAD method (which apparently is 86% of WEQAS scheme users) you would share with me what reference range you are using and where it's been derived from.
 
I am very happy to collate and post replies (anonymously, of course).
 
Thanks
Gemma