Impact of a new sampling buffer on faecal haemoglobin stability in a colorectal cancer screening programme by the faecal immunochemical test Grazia Grazzini a , Leonardo Ventura b , Tiziana Rubeca c , Stefano Rapi d , Filippo Cellai c , Pietro P. Di Dia a , Beatrice Mallardi a , Paola Mantellini a , Marco Zappa b and Guido Castiglione a Haemoglobin (Hb) stability in faecal samples is an important issue in colorectal cancer screening by the faecal immunochemical test (FIT) for Hb. This study evaluated the performance of the FIT-Hb (OC-Sensor Eiken) used in the Florence screening programme by comparing two different formulations of the buffer, both in an analytical and in a clinical setting. In the laboratory simulation, six faecal pools (three in each buffer type) were stored at different temperatures and analysed eight times in 10 replicates over 21 days. In the clinical setting, 7695 screenees returned two samples, using both the old and the new specimen collection device (SCD). In the laboratory simulation, 5 days from sample preparation with the buffer of the old SCD, the Hb concentration decreased by 40% at room temperature (25°C, range 22–28°C) and up to 60% at outside temperature (29°C, range 16–39°C), whereas with the new one, Hb concentration decreased by 10%. In the clinical setting, a higher mean Hb concentration with the new SCD compared with the old one was found (6.3 vs. 5.0 μg Hb/g faeces, respectively, P < 0.001); no statistically significant difference was found in the probability of having a positive result in the two SCDs. Better Hb stability was observed with the new buffer under laboratory conditions, but no difference was found in the clinical performance. In our study, only marginal advantages arise from the new buffer. Improvements in sample stability represent a significant target in the screening setting. European Journal of Cancer Prevention 26:285–291 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. European Journal of Cancer Prevention 2017, 26:285–291 Keywords: cancer prevention, colorectal cancer screening, faecal immunochemical test, sample stability a Screening Unit, b Clinical and Descriptive Epidemiology Unit, c Laboratory Unit, Cancer Prevention and Research Institute (ISPO) Florence and d General Laboratory, Laboratory Department, Careggi Hospital, Florence, Italy Correspondence to Grazia Grazzini, MD, Screening Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, Florence 50139, Italy Tel: +39 055 326 87279; fax: +39 055 326 97805; e-mail: g.grazzini@ispo.toscana.it Received 30 November 2015 Accepted 6 April 2016 Background Screening for colorectal cancer (CRC) using guaiac faecal occult blood tests (g-FOBT) has been shown to reduce CRC-related mortality (Hewitson et al., 2008). Faecal immunochemical tests (FIT) have gained international acceptance as the best candidate to succeed g-FOBT (Halloran et al., 2012). Recently, concerns have emerged about the stability of FIT samples. A study by Van Rossum et al. (2009) reported a significantly lower adenoma detection rate (DR) in delayed returned samples. Faecal haemoglobin (f-Hb) degradation seems to occur more frequently in FIT samples with respect to guaiac tests, probably because of the fact that globin chains degrade more rapidly than haem. As FIT analysis is based on antibodies specific for globin, false- negative results are more likely to occur if samples are exposed to globin degradation (Allison et al., 2014). Moreover, the degradation of Hb, because of bacterial enzymatic activity, may occur faster in samples collected in buffer as used by most quantitative FIT methods in comparison with the dry smears used for g-FOBT cards. A study carried out within our screening programme showed a seasonal variation in positivity rates because of the exposure of faecal samples to a high ambient tem- perature (Grazzini et al., 2010). Another analysis (Van Roon et al., 2012) showed that a prolonged sample return time up to 10 days did not affect detection of colonic lesions, although a seasonal variation in Hb concentration was observed. Recently, some changes in the specimen collection device (SCD) used in the OC Sensor system have been introduced by the manufacturer. Although overall chan- ges are not specified, the main differences arise in the composition of the buffer. This new formulation of the buffer could make f-Hb less susceptible to influence by timing or external physical factors. However, the che- mical composition of the new buffer is not available and no data are reported in the literature on the performance of the new SCD. The aim of this study was to compare the performance of the new SCD with the one being used currently in the Research paper 285 0959-8278 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/CEJ.0000000000000257 Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.