OBJECTIVES: The purpose of this study was to explore the impact of fatigue on patients with iron deficiency anemia (IDA) and to evaluate patients' understanding and interpretation of the FACIT-Fatigue scale in this patient population. Specifically, qualitative interviews with IDA patients were conducted to identify concepts associated with fatigue and their impact on patients, and to assess the content validity of the FACIT-Fatigue scale. METHODS: The study was a two-stage cross-sectional qualitative study that used a non-probabilistic purposive sampling strategy.  Study participants were recruited across three US clinical sites.  In-depth one-on-one concept elicitation/ cognitive interviews were conducted over the telephone.  In the initial concept elicitation portion of the interview, patients were asked to talk about their experiences with IDA in general before focusing more specifically on fatigue and other disease-related symptoms. The cognitive portion of the interview assessed the content of the FACIT-Fatigue and patients’ interpretation and understanding of the scale’s items, response options, instructions, and recall period. RESULTS: Fifteen IDA patients were interviewed.  The sample included a wide age range (mean 41.7; range 29 – 73), but included predominantly female patients (93.3%).  Analysis of the concept elicitation data found that patients spontaneously reported their main IDA symptoms to be fatigue (N=8), tiredness (N=13), and low energy (N=8).  Analysis of the cognitive interview data indicated that all 15 patients were able to interpret and understand the majority of the items on the FACIT-Fatigue, and felt that the items were relevant to their experience with IDA. CONCLUSIONS: The results of the concept elicitation and cognitive debrief interviews support the content validity of the FACIT-Fatigue scale within an IDA-specific patient population. The scale was confirmed to be meaningful, interpretable, and appropriate for use in an IDA patient population.