Self-triage, or the decision if and when to seek medical care is crucial, but also intrinsically difficult. The current study evaluates how the presence of competing diagnoses with differing severities influences participants' likelihood of seeking care. Participants were healthy undergraduate students from McMaster University. In a within-subjects design, participants rated the urgency with which they would seek medical care for a series of hypothetical scenarios. Each scenario included symptoms and either a low-severity diagnosis, a high-severity diagnosis, or a differential diagnosis where both high- and low-severity options were presented. Participants rated low-severity diagnoses as less urgent than high-severity diagnoses, as expected. Critically, when presented with both low- and high-severity options, participants rated scenarios with an intermediate level of urgency. Further analyses showed that participants appeared to base their urgency judgments on the low-severity diagnosis and then adjust their ratings upward when presented with a high-severity alternative. The results demonstrate that even when one of the possible diagnoses presented would require immediate care if accurate, ratings of urgency were significantly decreased if another less serious alternative was also suggested, potentially leading to sub-optimal decision-making. Implications of this observed pattern of self-triage decision-making are discussed.