Evaluation of the analytical performance of the novel NS-Prime system and examination of temperature stability of fecal transferrin compared with fecal hemoglobin as biomarkers in a colon cancer screening program.

OBJECTIVE: To examine the analytical aspects of fecal transferrin (Tf) and hemoglobin (Hb) measured on the NS-Prime analyzer for use in a colon cancer screening program. DESIGNS AND METHODS: Method evaluation and temperature stability studies for fecal Tf and Hb were completed. A method comparison was carried out against the NS-Plus system using samples collected from 254 screening program participants. A further 200 samples were analyzed to help determine suitable reference limits for fecal Tf using these systems. RESULTS: The assay for fecal Tf showed acceptable linearity, precision, and recovery, and showed minimal carryover with low potential for impact by the prozone effect. The 95th percentile for fecal Tf obtained for the reference population was 4.9 µg/g feces. The collection device sufficiently maintained fecal Tf and Hb stability for at least 7 days at room temperature, 4 °C, and -20 °C. Fecal Tf and Hb were most stable at 4 °C and -20 °C, but showed considerable loss (20-40%) of both proteins at 37 °C within the first 7 days. Mixing small amounts of blood into diluted fecal samples maintained at 37 °C for various time periods showed >50% loss of both proteins within 1 h of incubation. CONCLUSIONS: The NS-Prime analyzer showed acceptable performance for fecal Tf and Hb. These studies suggest that use of both Tf and Hb together as biomarkers will result in higher positivity rates, but this may not be attributed to greater stability of Tf over Hb in human feces.

Evaluation of Hemo Techt NS-Plus system for use in a province-wide colorectal cancer screening program.

OBJECTIVES: The NS-Plus automated analyzer and fecal immunochemical testing (FIT) testing system (Alfresa Pharma) was evaluated for use in Newfoundland and Labrador's provincial colorectal cancer (CRC) screening program. DESIGN AND METHODS: Various method performance characteristics were evaluated including the sample stability. The sensitivity for detecting neoplastic lesions was evaluated in 249 patients scheduled for colonoscopy. Each patient collected up to 2 samples for both guaiac based testing (Hemoccult SENSA; gFOBT) and FIT using the NS-plus system (cutoff=20 µg Hb/g feces or 100 µg Hb/L) over 2 days. Data was analyzed comparing 1- and 2-day testing strategies. RESULTS: The analyzer showed acceptable linearity, precision, and accuracy. The collection device maintained acceptable sample stability for at least 7 days at: 37 °C, room temperature (~23 °C), 4-8 °C, and -20 °C. The 2-day sampling strategy identified 30% (21 of 69) of all neoplastic lesions (low and high grade adenomas and CRC) including 2 of 4 high-grade adenomas and 2 of 2 CRCs. The single day strategy identified the same high-grade adenomas and CRCs but fewer low-grade adenomas (23% of all neoplasia). Reducing the screening cutoff to the estimated 95th percentile of FIT results in the healthy adult population (10 µg Hb/g feces), detected all high-grade adenomas in the 2-day strategy. CONCLUSIONS: The NS Plus automated analyzer system detects clinically significant neoplasms and shows acceptable performance for use in a CRC screening program with the potential for gains in sensitivity by modifying the number of days of screening or through lowering the cutoff.