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Many thanks for the replies so far, they are very much appreciated. Our indices are currently set up correctly, and none of the samples were outside of the cut offs defined by Roche. It is true that the haemolysis cut offs are very low for this assay, but our experience with haemolysis using spike and recovery experiments with haemolysate has demonstrated under recovery rather than over so doesn’t explain what we are seeing Delta bilirubin is a possibility and explains some direct bilirubin being present, but I don't think that this explains such a large proportion as we are seeing. Rob ________________________________ From: Wytze Oosterhuis [[log in to unmask]] Sent: 19 December 2013 19:32 To: Moore, Robert Subject: Re: Roche Direct Bilirubin assay query. Warning: This message contains unverified links which may not be safe. You should only click links if you are sure they are from a trusted source. Dear mr. Moore, I have the same inpression. Many patients we test with obvious Gilberts' syndrome have conjugated bilirubine>20%. >>> "Moore, Robert" 12/19/13 6:23 PM >>> Dear Mailbase I would be interested in hearing from people who are using the Roche direct bilirubin (Gen 2) assay on the COBAS 501/502. We have experienced a number of cases in which patients with a raised total bilirubin due to haemolytic conditions or possibly Gilberts’s syndrome (in which the bilirubin should be entirely unconjugated) are flagging as having direct bilirubin present. Each of these patients had otherwise normal LFTs (including GGT) and a low index of suspicion for cholestatic liver disease. Patient one: 16 year old male, diagnosed with hereditary spherocytosis and ?Gilbert’s syndrome. Total bilirubin 112 µmol/L (Ref range: up to 21 µmol/L) Direct bilirubin 9 µmol/L (Ref range: up to 5 µmol/L) Patient two: 63 year old female with haemolytic anaemia. Total bilirubin 70 µmol/L (Ref range: up to 21 µmol/L) Direct bilirubin 13 µmol/L (Ref range: up to 5 µmol/L) Patient three: 20 year old male, had LFTs measured following vomiting after EtOH consumption, and had repeat LFTs and direct bilirubin following an isolated raised total. Working diagnosis is Gilbert’s. Total bilirubin 21 µmol/L (Ref range: up to 21 µmol/L) Direct bilirubin 8 µmol/L (Ref range: up to 5 µmol/L) It is well documented that in direct bilirubin assays, there is some reactivity from unconjugated bilirubin however figures tend to be quoted at around 10-15% of the total. Our figures from patient one fits within that range, but patient two is higher at 18%, and patient three is higher again with 38% of the total. Have any other users of this assay out there seen similar effects with a very high “Crossreactivty” from unconjugated bilirubin in the direct bilirubin assay? Many thanks. Rob Moore Clinical Biochemistry Brighton and Sussex University Hospital This electronic message contains information from Brighton and Sussex University Hospitals NHS Trust, which may be privileged or confidential. The information is intended to be for the use of the individual(s) or entity named above. If you are not the intended recipient be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited and may be unlawful. If you have received this electronic message in error, please notify us immediately at [log in to unmask] and then delete any record of the message from your system. This Trust is committed to openness and transparency, and this commitment is supported by the Freedom of Information Act 2000. Under the Act, any recorded information held by the Trust, including this message, unless legally exempt, may be subject to public disclosure. 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