The excellent clinical outcome data demonstrated in many publications, require faecal haemoglobin cut-offs for referral for further investigation, at the low end of the analytical range of the available FIT systems.
The choice of laboratory method is therefore important to the objective evaluation of patients, not only for haemoglobin stability in the specimen collection device, but also for its low bias and small imprecision at the lower limit of the analytical working range.
Four FIT analytical systems were evaluated by the Guildford Medical Device Evaluation Centre (GMEC) in 2013.
The resulting report is available online: http://194.97.148.137/assets/downloads/pdf/activities/fit_reports/gmec_fit_evaluation_report.pdf
Evaluation of quantitative faecal immunochemical tests for haemoglobin. GMEC evaluation report Sept. 2013.Extracts of data from that report are represented here.
In this study, the HM-JACKarc system, supplied by Alpha Laboratories, was described as one of the more precise methods (Table 1). Its analytical working range correlated well to the expected values of spiked faecal samples. The ability to detect haemoglobin at both the lower and higher limits of the analytical range was confirmed (Figure 1). HM-JACKarc demonstrated a high sensitivity with a lower limit of detection of just 0.6 μg Hb/g faeces, making it ideal for symptomatic testing (Table 2). In addition, sample stability was proven at 20C throughout the 30 day period of the study (Table 3).
HM-JACKarc Performance Confirmed by GMEC: |
Stability of sample in the collection tube claims of the pack insert – 120 days at 4-8°C, 14 days at 25°C |
The Hook capacity greater than 200,000 μg of Hb / g faeces |
Linearity across the measurement range (7-400 μg of Hb / g faeces) |
Described as very sensitive at the low end with LOD as 0.6 μg of Hb / g faeces |