OBJECTIVES: In qualitative research, saturation reflects the point at which little or no new novel data can be elicited from an interview sample. Research suggests that saturation in symptom-focused concept elicitation (CE) studies can be demonstrated in samples with as few as 10 subjects. The objective of this study was to examine the applicability of these results to patient populations that are difficult to recruit and/or interview. METHODS:  A retrospective analysis of results from n=10 CE studies completed between 2014 and 2016 was conducted. Saturation was assessed by dividing each sample into chronological groups and comparing the number of unique concepts spontaneously elicited in the earlier groups to those emerging in the final group. RESULTS:  A total of 140 participants across 10 studies were included in this analysis with sample sizes ranging from N=8 to N=20 (M=14). Average age of participants was 40.8 years (SD=23.0) and sixty-seven (48%) were female. Therapeutic areas included rare genetic disorders (n=4), rare and advanced stage cancer (n=5), and a dermatological condition in adolescents (n=1). A total of 341 sign/symptom concepts were elicited across all studies with an average of 34 (SD=16.50, range=13 to 57 concepts) concepts per study. An average of 91.5% (range = 75.4% to 100%) of concepts across studies emerged within the first 75% of interviews. CONCLUSIONS:  Results from the present analysis are consistent with previous studies, can inform sample size decisions in qualitative research, and provide researchers working in rare disease or with vulnerable populations confidence that, if rigorously designed and conducted, their concept elicitation studies can be successful with sample sizes of 10 to 15 participants.