Precision or personalized medicine is taking us into an era of unprecedented breakthroughs in patient treatment and its progress depends to a great extent upon the best possible diagnostic testing. Optimizing test implementation at the laboratory level can be achieved efficiently and these improvements can directly impact and shape testing and patient outcomes. Real-time testing data suggest that significant gaps exist when it comes to patient access to treatment. Therefore, it is important to examine the reasons for these gaps and look at how they can be reduced to ensure that no patient misses out on the right targeted therapy.
The testing journey undergoes a number of stages which roughly break down as follows:
- The patient presents with symptoms of a certain condition
- To confirm a suspected diagnosis, a doctor decides which diagnostic test to use and then places an order for that test, or a series of tests
- The patient undergoes the test, usually as a tissue biopsy or a blood draw
- The blood or tissue sample is sent to a reference, commercial or hospital laboratory
- The sample is tested, perhaps more than once
- The sample may then be sent to another lab for molecular testing
- The result is interpreted and reported back to the doctor and patient
- The doctor then makes a clinical decision to prescribe an appropriate medication or treatment based on the results of the test
The complete process from start to finish is called ‘turnaround time’ and the length of this can vary not only based on the complexity of the test but also the logistics involved. The steps leading to the sample being tested are termed as ‘pre-analytical’ and several factors can lead to delays here. Test order forms and sample availability are two potential pre-analytical issues that can cause delays and subsequent gaps in patient treatment.
Test order (requisition) forms can differ between hospitals and laboratories and there is often no standardization for specific disciplines. A form may even include older versions of tests, ones with which physicians are familiar, when newer versions may be available. For an immunohistochemistry (IHC) test in lung cancer, for example, some forms detail specific IHC tests, whereas other labs have only general IHC request forms. Even if doctors believe a test is relevant, they may hesitate to order, stop using a test or maybe try another lab if they find the ordering or reporting process too complex. So improving the ease and clarity of test ordering could streamline the process and even speed turnaround time.
A requisition form that details the tests available by disease could be clearer and easier to work with, but with hundreds of diagnostic tests across all disciplines of pathology, and the chance of several different samples from one patient possibly going to microbiology, hematology, histology and cytology, the complexity around reaching standardization becomes evident. The laboratory, however, knowing exactly which diagnostic tests it can offer for a certain disease, could take the lead here.
A companion diagnostic test requires a sample such as blood or a tissue biopsy. Given the sometimes complex testing process from initial diagnosis to second, third and even fourth line testing, there is concern about the amount of sample available. The sequential testing of paraffin sections can be very wasteful on the amount of tissue used. If a section is required for fourth line testing there may be insufficient material left from the initial sample. One possible solution when there is limited sample availability for antibody validation can be to partner with a manufacturer of control material. A second option when testing for lung cancer, relates to the needle used to take a tissue biopsy. Evidence has shown that a 14-20 gauge needle (rather than a narrow gauge) can be used for biopsies and a biopsy using a 20G needle would yield sufficient material for all required tests. Ensuring there is adequate sample availability is another way to make sure patients do not lose out on the diagnosis they need to get the right medication at the right time driven by the right test.
Laboratories play such a vital role in precision medicine and ensuring patients are tested at an early stage. It is important to recognize and appreciate the service they provide but it is also critical to identify where the lab process can be improved to prevent patients missing out on the targeted therapies they need.
On December 5, 2017, Diaceutics is hosting a webinar discussing Why 50% of patients could be missing out on the right targeted therapy, which will go into more details about maximizing the number of patients being tested.