Does the mass of sample loaded affect faecal haemoglobin concentration using the faecal immunochemical test?

Area of Science:

• Clinical Diagnostics
• Gastroenterology
• Biochemistry

Background:

• Quantitative faecal immunochemical tests (FIT) for haemoglobin are vital for colorectal cancer (CRC) screening and diagnosis.
• Patient self-collection of faecal samples can introduce pre-analytical errors.
• The impact of sample mass on FIT results requires investigation.

Purpose of the Study:

• To evaluate if the mass of faecal sample collected affects faecal haemoglobin (f-Hb) concentration results.
• To assess the influence of different sample collection devices on f-Hb measurement accuracy.

Main Methods:

• Faecal samples with detectable f-Hb were loaded into four different collection devices.
• Increasing masses of faecal sample were used, including 'sample overloading'.
• Faecal haemoglobin concentration was measured using relevant analysers.

Main Results:

• Significant increases in faecal mass loaded onto collection probes were observed across all four devices.
• Despite increased faecal mass, faecal haemoglobin concentrations did not increase significantly for any device.
• Coefficient of variation for faecal mass was generally higher than for f-Hb results.

Conclusions:

• The mass of faecal sample loaded onto the probe does not significantly impact f-Hb results for the tested devices.
• Current FIT collection methods appear robust to variations in sample mass.
• This suggests a low risk of pre-analytical error related to sample mass in FIT.