Fig. 2: Impact of Flo Symptom Checker accuracy on incremental net monetary benefit (INMB) and diagnostic delay reduction: a two-way sensitivity analysis.

The left panel illustrates the effect on INMB at a willingness-to-pay threshold of $100,000 per QALY. The green zone represents combinations of accuracy thresholds where Flo SC remains cost-effective or reduces time to diagnosis, while the blue zone indicates scenarios where cost-effectiveness is not achieved or leads to further diagnostic delay. The right panel shows the effects on diagnostic delay reduction. Higher specificity is particularly critical for reducing diagnostic delay, as indicated by the green zone, while lower specificity results in minimal or even longer diagnostic delay.