Leading Edge 2021 Issue 2

www.alphalabs.co.uk 7 In the end, to avoid any risk of interference with the test, we decided to just wait and collect samples from the feeding dens where each gorilla was isolated, so that we could guarantee which faecal sample was from which animal. Sample Extraction Once we had the samples collected, we could begin the testing. We viewed the CALEX (sample extraction device) video on the website on how to deal with the various sample types. We found this really helpful. But, we quickly realised that gorilla faeces is nothing like human faeces – there really isn’t much ‘nutella’ portion. Our Gorillas have a mainly vegetable-based diet, but they eat lots of leaves and branches, so the faecal samples produced (excluding the episodes of diarrhoea) are extremely fibrous and were virtually impossible to obtain any soft material from without loads of fibres. After further discussion we modified the technique to sieve the sample through a tea strainer to remove the fibrous material, but that wasn’t an easy process. It took nearly a full pot of faeces to obtain sufficient soft material that we could then load onto the CALEX for extraction. Extended Range Quantum Blue fCAL We used the extended range BÜHLMANN Quantum Blue assay (LF-CALE25) which has a lower limit of 30µg/g. None of the samples we tested from the other gorillas came above this. But, Jock’s samples gave values of around the mid 70’s µg/g. This isn’t high compared to human levels, but may be significant as it was more than double the value in the ‘normal’ gorillas. To obtain a definitive diagnosis of IBD we would need to perform colonoscopy/biopsy, which we will look into doing as part of Jock’s next planned health check under general anaesthesia. The captive population for gorillas is quite small, but I am investigating the possibility of getting samples from other institutions across Europe, from animals with similar IBD symptoms. This will help acquire more data to correlate the results and hopefully validate with gut biopsies, for definitive confirmation, but that is a longer-term project. It would also be interesting to look at some of the smaller monkeys with marmoset wasting syndrome. There have been some publications using calprotectin to investigate this previously, before further invasive investigations are carried out. Sample processing for the smaller monkeys should also be easier as they eat less woody material. The project to look at faecal calprotectin concentrations within our population of gorillas has certainly been worthwhile. However, it did come with some unexpected challenges in the difficulty of actually extracting the samples compared to human faeces. Although the study was not conclusive, it does indicate that further evaluation would be beneficial, and at least we know how to modify the technique next time. Find out more about Quantum Blue® fCAL at www.calprotectin.co.uk Are you still using a guaiac method for faecal occult blood (FOB) detection? Qualitative faecal immunochemical tests (FIT) can be just as easy as traditional guaiac methods for near patient testing or when the requirement for a fast turnaround impedes the use of a quantitative FIT service. The DIAQUICK FOB cassette offers the specificity of a FIT in a simple yes/no manual test format: No Dietary Assay Interference It is common for guaiac-based methods to recommend adherence to a special diet in the days prior to testing. This is to avoid interference from peroxidases or animal haemoglobin, but is a distinct draw back when you need to test in an acute setting. There are no dietary restrictions when using the DIAQUICK FOB lateral flow assays, as these use antibodies that specifically bind human haemoglobin (Hb), with a sensitivity of 5µg Hb/g faeces. Specific, Sensitive, Simple Easy to perform ■ Result in 5 minutes ■ Specific for human Hb ■ Sensitivity 5µg Hb/g faeces ■ No dietary preparation required For more information on the DIAQUICK FOB Cassette, visit alphalabs.co.uk/ Z01101CE Detect Human Occult Blood in Faeces with the DIAQUICK FOB Cassette Immunochromatographic Lateral Flow Assay Is it time you moved on from gFOBT?