The Value of In Vitro Diagnostic Testing in Medical Practice: A Status Report

Abstract

Background: In vitro diagnostic (IVD) investigations are indispensable for routine patient management. Appropriate testing allows early-stage interventions, reducing late-stage healthcare expenditure (HCE).

Aim: To investigate HCE on IVDs in two developed markets and to assess the perceived value of IVDs on clinical decision-making. Physician-perceived HCE on IVD was evaluated, as well as desired features of new diagnostic markers.

Methods: Past and current HCE on IVD was calculated for the US and Germany. A total of 79 US/German oncologists and cardiologists were interviewed to assess the number of cases where: physicians ask for IVDs; IVDs are used for initial diagnosis, treatment monitoring, or post-treatment; and decision-making is based on an IVD test result. A sample of 201 US and German oncologists and cardiologists was questioned regarding the proportion of HCE they believed to be attributable to IVD testing. After disclosing the actual IVD HCE, the physician's perception of the appropriateness of the amount was captured. Finally, the association between physician-rated impact of IVD on decision-making and perceived contribution of IVD expenditure on overall HCE was assessed.

Results: IVD costs account for 2.3% and 1.4% of total HCE in the US and Germany. Most physicians (81%) believed that the actual HCE on IVDs was >5%; 19% rated the spending correctly (0-4%, p<0.001). When informed of the actual amount, 64% of physicians rated this as appropriate (p<0.0001); 66% of decision-making was based on IVD. Significantly, more physicians asked for either additional clinical or combined clinical/health economic data than for the product (test/platform) alone (p<0.0001).

Conclusions: Our results indicate a poor awareness of actual HCE on IVD, but a high attributable value of diagnostic procedures for patient management. New markers should deliver actionable and medically relevant information, to guide decision-making and foster improved patient outcomes.

Fig 1. Percentage of public and private HCE of GDP (pie) in the US and Germany in 2013.

Thin lines, public HCE; bold lines, private HCE without out-of-pocket; black fill, out-of-pocket HCE; white fill, rest of GDP (non-HCE) HCE, healthcare expenditure; GDP, gross domestic product; $B, US$ billion.

Fig 2

(A) Percentage of HCE on IVD in 2013 and (B) evolution of HCE on IVD 1993–2013. HCE, healthcare expenditure; IVD, in vitro diagnostics; $ B, US$ billion.

Fig 3. Causal loop diagram displaying the root causes for over- and under-utilization of IVD testing. Key drivers displayed in boxes; antecedents and secondary drivers displayed as plain text.

IVD, in vitro diagnostic; →(+), positive causal links amplifying the behavior of target variable.