UCSF Analysis Shows Why Diagnostics Need More Attention

A new analysis from UC San Francisco argues that diagnostics are being overlooked in the United States and worldwide, even though these medical tests are essential for matching patients to the right treatment. The authors say this gap is slowing progress against major diseases, especially as targeted therapies and precision health continue to advance.

The study notes that nearly half of the world’s population still lacks adequate access to diagnostics. It also points out that these tests receive less research and development investment than drugs and are reimbursed at lower rates by insurers. According to the authors, that imbalance creates barriers to innovation and makes it harder for patients to benefit from the right medical decisions at the right time.

Kathryn Phillips, lead author of the study published in Science, said, “Most people can easily understand how a new drug or surgery might help a patient. But the tests that guide medical decisions are just as critical.”

The analysis also argues that progress in therapies is moving faster than the development of the tests needed to guide their use. One example is GLP-1 drugs for obesity and diabetes, where many patients do not respond but few tests are available to predict who will benefit. Another example is Alzheimer’s disease, where new drugs can slow progression, but the blood tests that could help match patients to the most beneficial drugs cost about $1,000 and rarely receive insurance coverage, unlike the drugs themselves, which cost about $30,000 per year. As a result, doctors may have to make decisions without enough information, leaving some patients without the right treatment and others without treatment at all. 

The authors also stress that diagnostics are often treated separately from the therapies they support. The FDA reviews tests differently than drugs, and insurers pay for them differently as well. Drugs are also more likely than tests to receive expedited FDA review. Robert M. Califf, former FDA commissioner and co-author, said, “Regulatory and payment policy should evolve in tandem with scientific and technological advances,” adding that the current mismatch leaves “powerful tools on the shelf” and provides inadequate data for real-world decisions.

The paper outlines policy steps that could help, including reviewing tests and treatments together, streamlining test approvals, and improving how diagnostics are evaluated and paid for. Phillips said the goal is for patients, policymakers, insurers, and researchers to recognize diagnostics as essential to good health care, not an afterthought.