Redundant Tests There are some tests that were offered at MSFT that have been discontinued at RWT because they are no longer considered to be clinically useful. Chemistry Update Clinical Faecal Occult Blood Testing for Adults Faecal occult blood testing (FOBT) for adults is now considered to be a redundant and potentially misleading test in the investigation of symptomatic patients with suspected bowel cancer and patients with iron deficiency anaemia. NICE guideline CG27 (referral guidelines for suspected cancer) states “A patient who presents with symptoms suggestive of colorectal cancer should be referred to a team specialising in the management of lower GI cancer” and “in men with unexplained iron deficiency anaemia and a Hb ≤11g/dL or non-menstruating women with unexplained iron deficiency anaemia and a Hb ≤10g/dL, an urgent referral should be made”. The Bowel Cancer Screening programme will continue to use FOBT kits sent in the post to screening participants with samples analysed in Department of Health commissioned screening centres. There is still a clinical indication in children and so we will be sending samples for paediatric patients only to Birmingham Children’s Hospital for analysis. Please note that in these cases three samples from three different days are required. Urine Reducing Substances Urine reducing substances were traditionally performed in babies with prolonged jaundice as a surrogate marker for classical galactosaemia. This is not a suitable test for galactosaemia; if this disorder is suspected a galactosaemia screen should be carried out (lithium heparin (orange top) tube. If a baby has had a blood transfusion, galactosaemia screening will be invalid. In this situation please contact duty biochemist to discuss. Faecal Reducing Substances Faecal reducing substances are often unhelpful and frequently misleading because: They are not specific for lactase deficiency as any disorder that causes a rapid GI transit time will result in unabsorbed faecal sugars giving a positive reducing substance test. Many patients with a significant but transient reduction in lactase digestion/absorption will not give a positive reducing substances test due to bacterial degradation. Transient loss of lactase activity is a common phenomenon following GI infections in infants and young children. Consider persistence with current diet (to see if resolution occurs within a few days) or trial removal of lactose from the diet. If there is suspicion of cow’s milk allergy or there are persistent on-going or atypical symptoms consider paediatric referral. Urine Myoglobin For diagnosing rhabdomyolysis, serum creatine kinase is the test of choice because urine myoglobin: is unstable in urine lacks sensitivity because it only reaches the urine when renal tubular reabsorption is saturated cannot be differentiated from haematuria if a chemical test is used Further information is available from the duty biochemist. Telephone 01902 695290 or via email on [email protected] .