Table 1.

Development of text message intervention content and phrasing with respect to HBM^a constructs.

HBM construct	Text message phrasing/processes
Perceived susceptibility	We attempted to increase perceived susceptibility through using language such as “you may be at risk” and “your blood sugar levels may be high” and by indicating that they had not had a recent screening test.
Perceived severity	We limited text content related to perceived severity in consideration of the ethical implications of delivering alarming content without immediate access to a health care provider for discussion. We use phrases such as “this can lead to health problems” and included information about the importance of the detection and prevention of organ damage related to diabetes only in the web link content that had clear contact information for the research team, which included a physician.
Perceived benefits	We intended to increase perceived benefits through the use of language such as “take control of your health” and “you may benefit from” in text content and highlighted methods to manage health if the test was abnormal in the web link content.
Perceived barriers	We attempted to reduce the perceived barriers of cost, scheduling an appointment, and fasting before the test by indicating that the test is free (one can walk into a laboratory without scheduling an appointment/when it is convenient for them) and that there is no need to fast before the test in the text content.
Cues to action	The text message itself and follow-up reminders served as cues to action to trigger the decision-making process about going to a laboratory to get an HbA1cb test.
Self-efficacy	We sought to increases one’s self-efficacy by providing concise but comprehensive and clear information about how participants could complete the steps required to engage in HbA1c screening.

^aHBM: Health Belief Model.

^bHbA_1c: hemoglobin A_1c.