PROVIDING HARM ANCHORS IN VISUAL DISPLAYS OF TEST RESULTS MITIGATES PATIENT CONCERN ABOUT NEARLY NORMAL VALUES

Purpose: Patients can increasingly view laboratory test results directly via patient portals of electronic health record systems. Such systems typically only provide patients with one reference point (the "standard range") to use to interpret such hard-to-evaluate data. We tested novel visual displays designed to help patients who receive out-of-range test values to know how alarmed they should feel.

Methods: We conducted an online survey experiment using a demographically diverse panel in which participants viewed multiple hypothetical laboratory test results via an online portal. One group viewed these results on number line displays that were grey except for a green range labeled "standard range." The second group saw the same display that additionally included a harm anchor point labeled "many doctors are not concerned until here" (see Figure). Three results (platelet count, ALT, and serum creatinine) were initially reported as slightly outside of the standard range, and then participants viewed a second (similar) display showing a more extreme test result (i.e., one further from the standard range). For each test result, we measured participants' alarm about their results, their perceptions of urgency, and specific behavioral intentions. Participants also provided preference ratings of the display format.

Results: Providing the harm anchor reference point on the visual display significantly reduced both perceived alarm and perceived urgency of the close-to-normal ALT and creatinine results (all p's<0.001). Use of the harm anchor labels also reduced the number of participants who wanted to contact their doctor urgently or go to the hospital (ALT: 35% vs. 56%, p<.001; Creatinine: 35% vs. 57%, p<.001). The differences in perceived alarm and urgency disappeared when the test results were more extreme, indicating significantly greater sensitivity to variations in test result with the harm anchor labels. No significant differences were observed regarding the platelet count results. Participants had a small but significant preference for the harm anchor displays (p=0.02).

Conclusions: Presenting patients with cues regarding when test results become clinically concerning can sometimes minimize concern about out-of-range results that are not of immediate clinical concern. Providing harm anchor labels may be useful when designing patient-facing displays of health data in order to increase the signal specificity of such communications and to minimize patient requests for urgent appointments when routine follow-up would be sufficient.