Eliminating Pancreatic Insufficiency: However, we also identified that all samples that gave a negative result with the watery sample also produced a negative result with the formed sample. This means if you are able to report a result of >200µg/g on a watery sample then you are able to rule out pancreatic insufficiency as the cause of the symptoms and they don’t need to repeat it even though it wasn’t an ideal sample. In our audit, we found that 50% of watery samples gave results >200µg/g, enabling pancreatic insufficiency to be eliminated, so it is well worth processing these samples rather than rejecting and requesting a more formed sample. Mucoid Samples: The other thing we looked at in the initial review (2018 – 2020) was the impact of mucoid samples on the elastase results. There were 187 samples classified as mucoid, although the degree of mucus wasn’t noted and, as I am sure you are aware, some can be almost completely mucus whereas some are more formed with mucoid regions. We found that there wasn’t the big discrepancy in results that was observed with the liquid samples and no consistent finding of false positives (or false negatives) when results were compared with a non-mucoid sample from the same patient. We concluded that there is a much lower risk of reporting an erroneous low result from a mucoid sample compared to a watery sample. On the basis of this, we now ensure that we sample from non-mucoid regions of partially mucoid samples and do not test samples where this is not possible. As with liquid specimens, results >200ug/g are reported. However results <200ug/g from partially mucoid samples are reported but with a cautionary comment. Implementation of a New Testing Policy: We have now changed how we test and report elastase on watery samples. For a first time watery sample, if the result is above 200ug/g then this is reported, but if it is less than 200ug/g then we don’t report the result. Instead we append a comment stating that a watery sample was received and it may be unreliable, and ask for a repeat on a formed sample. This removes the possibility of an incorrect diagnosis being made on an unreliable sample. If a second watery sample is received then we will report the result in the format of a text report to ensure that the context/limitations are read rather than just the value in the results field, but to be honest we don’t get too many like this. Once this new pathway had been in place for 12 months we reaudited (May 2021 – April 2022) the data to seewhat the impact was. There were 56 samples identified as watery with values <200ug/g, and repeat samples were received from 15 of these (27%). This repeat rate is actually quite low which may imply that pancreatic insufficiency wasn’t the cause of the initial symptoms and a different diagnosis was subsequently made, or the patient just got better. Of the 15 samples provided for repeat testing, 14 were formed stools. Ten of the 15 repeat samples (67%) were found to be normal on repeat; a similar proportion to the original audit. The clinical notes from 20 patients with no repeat sample were reviewed – no reference was found to the faecal elastase test in any of the notes examined. Four patients had a previous diagnosis of pancreatic insufficiency or had a diagnosis made based on other evidence. There was no reference to PERT or pancreatic insufficiency in the remaining 16 patients, indicating that the lack of the initial reported result didn’t have a significant impact on the patient pathway. The main take home message is don’t reject watery samples for elastase testing – test them, because from our audit, you can eliminate pancreatic insufficiency in about 50% of watery samples and this will help direct patients to other diagnostic pathways.” www.calprotectin.co.uk/calex Turbo Charge Your Faecal Testing The BÜHLMANN fCAL® turbo and fPELA assays will revolutionise your faecal calprotectin and elastase testing with a streamlined workflow. Same CALEX® extraction for both assays: - One extraction two tests - 7 days ambient stability post extraction CALEX® can be given to patients for sample collection - Ambient, fridge and freezer stability for a flexible return to laboratory workflow Wide assay range provides valuable clinical insight and keeps dilutions to a minimum - Calprotectin: 20 – 2000µg/g (autodilute to 8000µg/g) - Elastase: 10 - 500µg/g Time to first result is 10 minutes, with further results every few seconds Protocols available for most clinical chemistry analysers - Including Abbott, Beckman, Roche, Siemens as well as stand-alone options Calibrators, controls and reagents are all in a stable, ready to use format and they don’t need to be lot matched Contact Alpha Laboratories today to find out more. 03_Calex_Workflow_April2023.indd 1 28/02/2023 10:20:05 www.alphalabs.co.uk © 2023 Copyright Alpha Laboratories Ltd. 11
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