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

Abstract

ObjectiveTo 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 methodsMethod 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.ResultsThe 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.ConclusionsThe 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 sample stability for a quantitative faecal immunochemical test and comparison of two sample collection approaches

“…3 Most publications on f-Hb sample stability have focused on the stability of f-Hb after sample collection into specialized collection devices. [11][12][13] Previous work on stability of f-Hb in faeces using FIT methodology utilized normal faeces spiked with haemoglobin and showed rapid instability at room temperature. 10 Most diagnostic accuracy studies using FIT have provided patients with a specialized collection device for sample collection.…”

Systematic scoping review: Use of the faecal immunochemical test residual buffer to enhance colorectal cancer screening

“…Furthermore, 15 studies were identified by our search strategy of literature that studied biomarkers in FIT buffer from FIT samples that had been created by lab personnel (rather than patients) from patient whole stool samples. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] These studies were not included in this systematic scoping review since the technique to obtain the sample (capturing a whole stool) and the placement into the device (spiking by lab personnel) could impact both the stability of the biomarkers detected and the test characteristics for the biomarkers examined. For example, transporting whole stool to the lab may be associated with more degradation in transit or the lab personnel may spike greater stool into the FIT collection device than might be accomplished in actual clinical practice from a patient.…”

“…Furthermore, 15 studies were identified by our search strategy of literature that studied biomarkers in FIT buffer from FIT samples that had been created by lab personnel (rather than patients) from patient whole stool samples 41–55 . These studies were not included in this systematic scoping review since the technique to obtain the sample (capturing a whole stool) and the placement into the device (spiking by lab personnel) could impact both the stability of the biomarkers detected and the test characteristics for the biomarkers examined.…”