The tpi-targeting real-time PCR assay had poor sensitivity when diagnostic 18S real-time PCR Ct values were > 30 (particularly when targeting the G. duodenalis assemblage A tpi locus) and when attempting to confirm mixed-assemblage infections, regardless of diagnostic 18S Ct value (again, predominantly as a result of poor success in detecting and amplifying the G. duodenalis assemblage A tpi locus). Here, TPI1 is linked to infection.