The study delves into determining the detection thresholds for the prickle effect in Llama fiber knitted fabrics, crucial for fabric acceptability assessment, by consumers of garments made from natural fibers. Employing standard evaluation methods involving moistened skin and perception scoring, coupled with the identification of objectionable (coarse) fiber content as a pivotal variable, the research using 41-invited panelist elucidates the intricate interplay between fiber characteristics (diameter) and prickle perception. Despite efforts to mitigate hairiness through finishing processes, the study unveils the nuanced impact of fiber protrusion on the prickle effect, necessitating a comprehensive evaluation approach. Through pairwise comparisons and perception scales, the study unveils strong associations between prickle perception and expression degrees, reaffirming panelists’ sensitivity in detecting subtle variations. Statistical analyses underscore significant differences in coarse fiber content and diameter between paired samples, further corroborating panelists’ discernment. It can be clearly concluded, from this analysis, the prickle effect detection thresholds in llama fiber fabrics range from 2.36 to 2.42% in coarse fiber differences and from 0.11 to 1.63 microns in fiber diameter difference, in the 95% of the tested cases or more probability. In conclusion, the study delineates critical thresholds (2.36%) for prickle detection in Llama fiber fabrics, offering invaluable insights for fabric evaluation and refinement processes, and emphasizing the heightened sensitivity of finished fabric samples in prickle perception.