Clin Chem Lab Med 2015; 53(3): e69–e71

Letter to the Editor Yoon-Hee Lee, Mina Hur*, Hanah Kim, Kyung Nam Jeon, Cheong-Ha Yun, Chang Ho Lee and Han-Ik Cho

Optimal cut-off concentration for a faecal immunochemical test for haemoglobin by Hemo Techt NS-Plus C15 system for the colorectal cancer screening DOI 10.1515/cclm-2014-0442 Received April 24, 2014; accepted July 24, 2014; previously published online August 15, 2014

Keywords: colorectal cancer; cut-off concentration; faecal immunochemical test; NS-Plus C; screening. To the Editor, Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide, showing an increasing trend of incidence [1]. A high incidence of CRC could be explained not only by the changes in risk factors but also by the widespread use of CRC screening. Regular CRC screening is recommended for average-risk men and women aged 50 years or older, and faecal immunochemical test (FIT) is recommended as the test of choice for population-based screening [2–4]. Faecal haemoglobin concentrations (f-Hb) can be measured using automated FIT systems, which involve immunoturbidimetry. However, the optimal number of samples and the optimal cut-off concentrations has to suit local resources and the acceptability of missed cancers [4]. A few recent studies evaluated the clinical performances of FIT using Hemo Techt NS-Plus C system (NSPlus C, Alfresa Pharma Co., Osaka, Japan) for the detection of CRC [5–7]. Those studies, however, were performed on *Corresponding author: Mina Hur, MD, PhD, Department of Laboratory Medicine, Konkuk University School of Medicine, Konkuk University Hospital, 120-1 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul 143-729, Korea, Phone: +82 2 20305581, Fax: +82 2 26366764, E-mail: [email protected] Yoon-Hee Lee, Kyung Nam Jeon, Cheong-Ha Yun, Chang Ho Lee and Han-Ik Cho: Korean Association of Health Promotion, Seoul, Korea Hanah Kim: Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Korea

symptomatic, high-risk patients using a standard cut-off concentration of 19 μg Hb/g faeces and a 2-day screening protocol. In the present study, we investigated which cut-off concentration would be optimal to screen CRC in an average-risk population using NS-Plus C. The study population consisted of 1397 individuals (670 men and 727 women) who received annual physical check-up at the Gangnam branch of Korean Association of Health Promotion (KAHP), during the period between July 2012 and March 2013. Their age ranged from 50  years to 76 years (median age of 58 years). In all the participants, both colonoscopy and FIT were performed as a routine CRC screening, and these results were retrospectively analysed. For FIT, faecal samples were obtained at home within 1 or 2 days prior to physical check-up, using a single sample screening protocol. The study population was divided into four groups by the colonoscopic results: normal and incidental pathology other than neoplasia; low-risk adenoma (  1 cm diameter or villous in nature or showing high-grade dysplasia); and CRC. All the participants were without personal history of CRC. Technicians who read the f-Hb were blinded to colonoscopy results, and colonoscopists were blinded to f-Hb. This study was approved by the Institutional Review Board of KAHP. KAHP is a specialised healthcare institute, which provides health check-ups to over 1,000,000 individuals annually in 16 branch clinics nationwide in Korea. FIT was performed on the day of receipt in the laboratory on a single NS-Plus C analyser, according to the manufacturer’s instruction. Briefly, NS-Plus C system uses a plastic serrated tip sampling probe to transfer 10  mg of faecal samples into a flat tube containing a 1.9  mL of stabilising fluid. One drop (12 μL) of sample mixture is applied to NS-Plus C analyser; then 130 μL of buffer and 40 μL of colloidal gold anti-human Hb

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e70      Lee et al.: Cut-off concentration for FIT by NS-Plus C

200

f-Hb (µg Hb/g faeces)

150

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0 Normal/incide Low-risk ntal pathology adenoma other than (n=1059) neoplasia (n=317)

High-risk adenoma (n=7)

Colorectal cancer (n=14)

Figure 1 Distribution of f-Hb by colonoscopic results (n = 1397). Horizontal bars show the medians of f-Hb: 3.8 μg Hb/g faeces (normal/incidental pathology other than neoplasia); 3.8 μg Hb/g faeces (low-risk adenoma); 9.5 μg Hb/g faeces (high-risk adenoma); and 115.2 μg Hb/g faeces (colorectal cancer). f-Hb were significantly associated with the colonoscopic results (p 

Optimal cut-off concentration for a faecal immunochemical test for haemoglobin by Hemo Techt NS-Plus C15 system for the colorectal cancer screening.

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