There is a need for specific and inexpensive rapid point of care (POC) diagnostic tests that can be used for clinical management of infectious diseases. Diagnostics are important as they allow tailoring treatment with antibacterial drugs, reducing unnecessary antibacterial drug use and thereby delaying the development of antibacterial resistance. However, the tools need to be readily available at point-of-care and cost-effective, such as the rapid strep test. Additionally, the tools that work best are technologies that can be used across the entire patient population. Given the potential complexity of some of these tests, there also needs to an educational component so healthcare practitioners know how to use the tests and be able to interpret the test results.
At present, it takes about 3 days (and sometimes a week) to identify organisms. If such tests could be done more expeditiously, physicians can institute a narrower antibacterial drug therapy relieving the pressure in terms of selecting resistant organisms (by using antibacterial drugs that are ineffective against the organism, one starts selecting out mutants that are more resistant and become more resistant over time).
The different types of rapid POC diagnostic tools for bacterial diseases currently available in the market may be imperfect; they may be costly, not particularly fast, or otherwise limited in scope. Some of these diagnostics include:
- PNA FISH test – The test is done on a positive blood culture and reportedly returns results in 24-36 hours. Additionally, laboratories reportedly have found it difficult to incorporate this test into their workflow.
- BioFire Diagnostics FilmArray® System – This molecular assay can identify 17 viruses and 4 bacteria within an hour, but currently costs around $300 (although price will likely go down in the future).
- Procalcitonin (PCT) – This is a test used in some hospitals to diagnose sepsis or to rule it out. However, because the test does not reveal whether the infection is multi-drug resistant, it is not widely adopted.
One of the challenges that relate to the use of rapid POC diagnostics is the existence of a range of organisms residing on the body without causing infections, which makes it difficult to pinpoint which bacteria are actually causing the infection. By adjusting the cut-off result in molecular assays to distinguish colonized from organisms actually causing the signs and symptoms of infection, this issue has been partially mitigated. However, this factor may impact the acceptance of rapid POC diagnostics by healthcare providers.
5.1 Rapid POC Diagnostic Private ENPV Model Parameters and Assumptions
For the purposes of modeling the decision-making process and expected returns for a rapid point-of-care diagnostic producer, we selected a new rapid point-of-care diagnostic designed to identify methicillin-resistant Staphylococcus aureus (MRSA) that can cause serious infections, such as skin or wound infections, pneumonia, or infections of the blood. While community acquired MRSA is on the rise, in this analysis, we focused primarily on healthcare–associated MRSA infections, which occur in hospitals and nursing homes. The selection of MRSA is based on the fact that there are 1) diagnostic tests on the market and under development for the infection and 2) published studies with MRSA-specific quantitative information that can be used in our modeling.
Table 21 presents the point estimates for the private ENPV model parameters and assumptions for the rapid point-of-care diagnostics for bacterial infectious disease. The following sections discuss the basis for these estimates in further detail.
Table 21: Private ENPV Model Parameters and Assumptions for a Rapid POC Diagnostic for MRSA
5.2 Rapid POC Diagnostic Social EPV Model Parameters and Assumptions
The framework used to assess social benefits for a new MRSA rapid POC diagnostic is the same as that used for antibacterial drugs and vaccines as described earlier in this report. We use the same values for the real annual social discount rate, VSL, and VSLY as in the antibacterial drugs model. Table 24 presents the point estimates for the social EPV model parameters and assumptions. The following sections discuss the basis for these estimates in further detail.
Table 24: Social EPV Model Parameters and Assumptions for a MRSA Rapid POC Diagnostic
5.3 Rapid POC Diagnostic Social EPV Results
We estimate the social EPV of a new MRSA rapid POC diagnostic at $22.1 billion. Comparison of the social ENPV value to private ENPV shows that the social EPV is substantially higher than the private ENPV by $21.9 billion. When a Monte Carlo analysis was conducted to gauge the sensitivity of our results to changes in model parameters and assumptions, we find that the social EPV could potentially range from $6.0 billion to $73.4 billion. The primary drivers for the observed wide range of social EPV results include 1) expected MRSA transmission rate, 2) real annual social rate of discount, 3) clinical stage success probability, and 4) percentage of patients with MRSA infection that die.
The results of this analysis, however, are limited to rapid POC diagnostics developed for MRSA and likely reflect the lower costs of development through the 510(k) process and the greater demand for a MRSA rapid POC diagnostic.