How "should" we write guideline recommendations? Interpretation of deontic terminology in clinical practice guidelines: survey of the health services community.

OBJECTIVE: To describe the level of obligation conveyed by deontic terms (words such as "should", "may", "must" and "is indicated") commonly found in clinical practice guidelines. DESIGN: Cross-sectional electronic survey. SETTING: A clinical scenario was developed by the researchers, and recommendations containing 12 deontic terms and phrases were presented to the participants. PARTICIPANTS: All 1332 registrants of the 2008 annual conference of the US Agency for Healthcare Research and Quality. MAIN OUTCOME MEASURES: Participants indicated the level of obligation they believed guideline authors intended by using a slider mechanism ranging from "No obligation" (leftmost position recorded as 0) to "Full obligation" (rightmost position recorded as 100.) RESULTS: 445/1332 registrants (36%) submitted the on-line survey; 254/445 (57%) reported that they have experience in developing clinical practice guidelines; 133/445 (30%) indicated that they provide healthcare. "Must" conveyed the highest level of obligation (median = 100) and least amount of variability (interquartile range = 5.) "May" (median = 37) and "may consider" (median = 33) conveyed the lowest levels of obligation. All other terms conveyed intermediate levels of obligation characterised by wide and overlapping interquartile ranges. CONCLUSIONS: Members of the health services community believe guideline authors intend variable levels of obligation when using different deontic terms within practice recommendations. Ranking of a subset of terms by intended level of obligation is possible. Matching deontic terminology to the intended recommendation strength can help standardise the use of deontic terminology by guideline developers.

Aqueous-based microcapsules are detected primarily in gut-associated dendritic cells after oral inoculation of mice.

We previously found that aqueous-based microencapsulation enhanced virus-specific humoral immune responses after oral inoculation of mice. However, the mechanism by which microencapsulation enhances immunogenicity remains unclear. We found that spermine-alginate microcapsules were detected primarily in gut-associated dendritic cells (i.e. CD11c/CD18+, Ia+, CD11b-, CD45R-) after oral inoculation of adult mice. Microencapsulation may enhance immunogenicity by involving antigen presenting cells which are more efficient than those recruited during natural infection.