When laboratory values lose their frame of reference: missing reference intervals in layperson questions in an online health forum

Abstract Objectives Direct patient access to laboratory results and the widespread use of AI-based chatbots for medical information have shifted laboratory value interpretation into digital, largely unsupervised settings. Because numerical laboratory values are only meaningful when interpreted against appropriate reference intervals, this study investigated whether laypersons provide this essential context when seeking online advice. Methods A retrospective analysis was conducted of 207 complete blood count–related questions posted on the Reddit forum AskDocs between October 2021 and May 2023. Extracted variables included self-reported age and gender, title and text length, and the presence or absence of reference intervals and units. Descriptive statistics and group comparisons were performed using nonparametric tests. Results In 55 % (114/207) of the laboratory medicine–related questions, no reference intervals were provided, and in 51 % (106/207) no units were specified. The inclusion of units was a strong predictor of the presence of reference intervals (OR=5.03; 95 % CI 2.81–9.22; p<0.001). Posts that included reference intervals were significantly longer than those without such information (median 160 vs. 126 words; p=0.004). Age and sex did not differ significantly between the groups. Conclusions Layperson inquiries about laboratory results in online health forums frequently lack essential contextual information required for valid interpretation. The widespread omission of reference intervals and units underscores persistent challenges in health literacy and highlights the need for improved laboratory reporting formats and patient-oriented interpretive support.