Pitfalls and Preparation: Responding to the Growth of Consumer Genetic Testing

By Joel Diamond, MD, FAAFP

Many healthcare providers face an unprecedented situation: patients are outpacing their physicians’ interest in, and understanding of, genetic and genomic testing. More tests are available through commercial interests like 23andMe – which means patients are arriving at appointments with results in hand and preconceptions (or misconceptions) in mind.

In some ways, this is a good thing. Heightened consumer awareness about any advance in healthcare is positive. An educated, engaged patient population is undeniably beneficial to all stakeholders.

But some aspects of the current “inside-out” dynamic are problematic. Providers must be conscious of the pitfalls that might accompany test results patients acquire commercially.

Limitations of DTC tests

To begin with, direct-to-consumer tests (DTC) are not necessarily certified by the Clinical Laboratory Improvement Amendments (CLIA) and therefore are regulated far less rigorously than clinical genomic tests, calling into question their quality and accuracy. For providers to factor information from DTC tests into clinical decisions, in fact, the FDA requires that results be confirmed through repeated, clinician-ordered CLIA-certified testing. 

Second, DTC tests often reveal “traits” rather than true medical insights. Commercial organizations do not typically perform next-generation sequencing (NGS), but instead often just look at a specific area of the DNA (i.e., a single nucleotide polymorphisms or SNP). SNPs reveal only common, well-known gene variants, but consumers often misunderstand the breadth and significance of the test and wrongly assume they are getting true medical information. 

Consider this example: an SNP shows an error in the DNA base code (perhaps an “A” appears where a “T” typically is located). Population studies show that people with curly hair typically have this mutation. However, not all individuals with this mutation end up with curly hair. The generalized and limited nature of SNP information might cause a patient to jump to a conclusion about their hair (or, when extrapolated to a disease-specific example, their medical risk) – when it indicates only a trait shared by a particular percentage of a larger population. 

Beyond SNPs, some DTC tests examine specific genes like BRCA 1 and 2, which helps identify risk for breast, ovarian and prostate cancer. But results represent only a handful of the thousands of genetic variations associated with these cancers, some carried on genes other than BRCA 1 and 2. If a patient does not understand this, they may view the commercial BRCA 1 or 2 test as a definitive indicator (“yes, you are at risk” or “no, you are not at risk”). 

This incomplete information could affect personal healthcare decisions going forward. Some who believe their risk factors mean they surely will develop breast cancer, for example, might undergo an unnecessary radical double mastectomy. Others who believe they are not at risk might swing to the other end of the spectrum, even to the point of neglecting important self-care (like breast exams) or screenings (like mammograms) – or even refusing future genomic testing because they feel completely safe from these heritable cancers. 

Clearly, when these tests are undertaken outside of the clinical realm, consumers cannot avail themselves of the critical perspective, context and guidance their healthcare team can offer.

Barriers to usability

Let us also look at several prosaic implications of this DTC trend.

Commercial testing companies typically return test results on paper, or perhaps via emailed PDF. What are providers going to do when patients walk into their offices and hand over these documents? The situation is similar to the recent upswing in commercial MRI services – where consumers are promised clinical-quality MRIs, at a reasonable cost, without a physician referral. Patients ultimately bring their results to their physicians.

The information may not be in a format that the provider can even access (e.g., a file that cannot be opened). Even if the results can be viewed, interoperability barriers prevent them from being integrated as discrete data, actionable within context of the patient’s clinical information.

DTC tests lack one additional critical attribute: they are not ordered or conducted within any relevant medical context. Providers cannot tie the results to a set of symptoms or clinical indicators. This means they are presented with a large volume of DTC test data that A) may or may not be accurate or complete; B) cannot be meaningfully used within their workflow; and C) may not be linked to the patient’s current condition or phenotype.

Where does all of these leave us? Certainly, clinically ordered and interpreted genetic and genomic testing is here to stay and, in fact, is considered the new standard of care. Equally certainly, commercial vendors will expand their offerings of DTC tests because profits can be made. 

To ensure the full value is realized, individual clinicians and provider organizations must accelerate their understanding of genomics. They must educate themselves so they can provide the expert guidance patients seek. Additionally, they must adopt the necessary technologies to effectively manage the voluminous data sets inherent to genomic testing so the insights can be used within the clinical workflow to improve care and outcomes.

JOEL DIAMOND, MD, FAAFP, is Adjunct Associate Professor of Biomedical Informatics at the University of Pittsburgh. He is a diplomat of the American Board of Family Practice and a fellow in the American Academy of Family Physicians. He cares for patients at Handelsman Family Practice in Pittsburgh and serves as Chief Medical Officer for 2bPrecise.

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