Charity Watkins sensed something was deeply wrong when she experienced exhaustion after her daughter was born.

At times, Watkins, then 30, had to stop on the stairway to catch her breath. Her obstetrician said postpartum depression likely caused the weakness and fatigue. When Watkins, who is Black, complained of a cough, her doctor blamed the flu.

About eight weeks after delivery, Watkins thought she was having a heart attack, and her husband took her to the emergency room. After a 5½-hour wait in a North Carolina hospital, she returned home to nurse her baby without seeing a doctor.

When a physician finally examined Watkins three days later, he immediately noticed her legs and stomach were swollen, a sign that her body was retaining fluid. After a chest X-ray, the doctor diagnosed her with heart failure, a serious condition in which the heart becomes too weak to adequately pump oxygen-rich blood to organs throughout the body. Watkins spent two weeks in intensive care.

She said a cardiologist later told her, “We almost lost you.”

Watkins is among 12 million adults misdiagnosed every year in the U.S.

In a study published Jan. 8 in JAMA Internal Medicine, researchers found that nearly 1 in 4 hospital patients who died or were transferred to intensive care had experienced a diagnostic error. Nearly 18% of misdiagnosed patients were harmed or died.

In all, an estimated 795,000 patients a year die or are permanently disabled because of misdiagnosis, according to a study published in July in the BMJ Quality & Safety periodical.

Some patients are at higher risk than others.

Women and racial and ethnic minorities are 20% to 30% more likely than white men to experience a misdiagnosis, said David Newman-Toker, a professor of neurology at Johns Hopkins School of Medicine and the lead author of the BMJ study. “That’s significant and inexcusable,” he said.

Researchers call misdiagnosis an urgent public health problem. The study found that rates of misdiagnosis range from 1.5% of heart attacks to 17.5% of strokes and 22.5% of lung cancers.

Weakening of the heart muscle — which led to Watkins’ heart failure — is the most common cause of maternal death one week to one year after delivery, and is more common among Black women.

Heart failure “should have been No. 1 on the list of possible causes” for Watkins’ symptoms, said Ronald Wyatt, chief science and chief medical officer at the Society to Improve Diagnosis in Medicine, a nonprofit research and advocacy group.

Maternal mortality for Black mothers has increased dramatically in recent years. The United States has the highest maternal mortality rate among developed countries. According to the Centers for Disease Control and Prevention, non-Hispanic Black mothers are 2.6 times as likely to die as non-Hispanic white moms. More than half of these deaths take place within a year after delivery.

Research shows that Black women with childbirth-related heart failure are typically diagnosed later than white women, said Jennifer Lewey, co-director of the pregnancy and heart disease program at Penn Medicine. That can allow patients to further deteriorate, making Black women less likely to fully recover and more likely to suffer from weakened hearts for the rest of their lives.

Watkins said the diagnosis changed her life. Doctors advised her “not to have another baby, or I might need a heart transplant,” she said. Being deprived of the chance to have another child, she said, “was devastating.”

Racial and gender disparities are widespread.

Women and minority patients suffering from heart attacks are more likely than others to be discharged without diagnosis or treatment.

Black people with depression are more likely than others to be misdiagnosed with schizophrenia.

Minorities are less likely than whites to be diagnosed early with dementia, depriving them of the opportunities to receive treatments that work best in the early stages of the disease.

Misdiagnosis isn’t new. Doctors have used autopsy studies to estimate the percentage of patients who died with undiagnosed diseases for more than a century. Although those studies show some improvement over time, life-threatening mistakes remain all too common, despite an array of sophisticated diagnostic tools, said Hardeep Singh, a professor at Baylor College of Medicine who studies ways to improve diagnosis.

“The vast majority of diagnoses can be made by getting to know the patient’s story really well, asking follow-up questions, examining the patient, and ordering basic tests,” said Singh, who is also a researcher at Houston’s Michael E. DeBakey VA Medical Center. When talking to people who’ve been misdiagnosed, “one of the things we hear over and over is, ‘The doctor didn’t listen to me.’”

Racial disparities in misdiagnosis are sometimes explained by noting that minority patients are less likely to be insured than white patients and often lack access to high-quality hospitals. But the picture is more complicated, said Monika Goyal, an emergency physician at Children’s National Hospital in Washington, D.C., who has documented racial bias in children’s health care.

In a 2020 study, Goyal and her colleagues found that Black kids with appendicitis were less likely than their white peers to be correctly diagnosed, even when both groups of patients visited the same hospital.

Although few doctors deliberately discriminate against women or minorities, Goyal said, many are biased without realizing it.

“Racial bias is baked into our culture,” Goyal said. “It’s important for all of us to start recognizing that.”

Demanding schedules, which prevent doctors from spending as much time with patients as they’d like, can contribute to diagnostic errors, said Karen Lutfey Spencer, a professor of health and behavioral sciences at the University of Colorado-Denver. “Doctors are more likely to make biased decisions when they are busy and overworked,” Spencer said. “There are some really smart, well-intentioned providers who are getting chewed up in a system that’s very unforgiving.”

Doctors make better treatment decisions when they’re more confident of a diagnosis, Spencer said.

In an experiment, researchers asked doctors to view videos of actors pretending to be patients with heart disease or depression, make a diagnosis, and recommend follow-up actions. Doctors felt far more certain diagnosing white men than Black patients or younger women.

“If they were less certain, they were less likely to take action, such as ordering tests,” Spencer said. “If they were less certain, they might just wait to prescribe treatment.”

It’s easy to see why doctors are more confident when diagnosing white men, Spencer said. For more than a century, medical textbooks have illustrated diseases with stereotypical images of white men. Only 4.5% of images in general medical textbooks feature patients with dark skin.

That may help explain why patients with darker complexions are less likely to receive a timely diagnosis with conditions that affect the skin, from cancer to Lyme disease, which causes a red or pink rash in the earliest stage of infection. Black patients with Lyme disease are more likely to be diagnosed with more advanced disease, which can cause arthritis and damage the heart. Black people with melanoma are about three times as likely as whites to die within five years.

The covid-19 pandemic helped raise awareness that pulse oximeters — the fingertip devices used to measure a patient’s pulse and oxygen levels — are less accurate for people with dark skin. The devices work by shining light through the skin; their failures have delayed critical care for many Black patients.

Seven years after her misdiagnosis, Watkins is an assistant professor of social work at North Carolina Central University in Durham, where she studies the psychosocial effects experienced by Black mothers who survive severe childbirth complications.

“Sharing my story is part of my healing,” said Watkins, who speaks to medical groups to help doctors improve their care. “It has helped me reclaim power in my life, just to be able to help others.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.

Subscribe to KFF Health News’ free Morning Briefing.

One January morning in 2021, Carol Rosen took a standard treatment for metastatic breast cancer. Three gruesome weeks later, she died in excruciating pain from the very drug meant to prolong her life.

Rosen, a 70-year-old retired schoolteacher, passed her final days in anguish, enduring severe diarrhea and nausea and terrible sores in her mouth that kept her from eating, drinking, and, eventually, speaking. Skin peeled off her body. Her kidneys and liver failed. “Your body burns from the inside out,” said Rosen’s daughter, Lindsay Murray, of Andover, Massachusetts.

Rosen was one of more than 275,000 cancer patients in the United States who are infused each year with fluorouracil, known as 5-FU, or, as in Rosen’s case, take a nearly identical drug in pill form called capecitabine. These common types of chemotherapy are no picnic for anyone, but for patients who are deficient in an enzyme that metabolizes the drugs, they can be torturous or deadly.

Those patients essentially overdose because the drugs stay in the body for hours rather than being quickly metabolized and excreted. The drugs kill an estimated 1 in 1,000 patients who take them — hundreds each year — and severely sicken or hospitalize 1 in 50. Doctors can test for the deficiency and get results within a week — and then either switch drugs or lower the dosage if patients have a genetic variant that carries risk.

Yet a recent survey found that only 3% of U.S. oncologists routinely order the tests before dosing patients with 5-FU or capecitabine. That’s because the most widely followed U.S. cancer treatment guidelines — issued by the National Comprehensive Cancer Network — don’t recommend preemptive testing.

The FDA added new warnings about the lethal risks of 5-FU to the drug’s label on March 21 following queries from KFF Health News about its policy. However, it did not require doctors to administer the test before prescribing the chemotherapy.

The agency, whose plan to expand its oversight of laboratory testing was the subject of a House hearing, also March 21, has said it could not endorse the 5-FU toxicity tests because it’s never reviewed them.

But the FDA at present does not review most diagnostic tests, said Daniel Hertz, an associate professor at the University of Michigan College of Pharmacy. For years, with other doctors and pharmacists, he has petitioned the FDA to put a black box warning on the drug’s label urging prescribers to test for the deficiency.

“FDA has responsibility to assure that drugs are used safely and effectively,” he said. The failure to warn, he said, “is an abdication of their responsibility.”

The update is “a small step in the right direction, but not the sea change we need,” he said.

Europe Ahead on Safety

British and European Union drug authorities have recommended the testing since 2020. A small but growing number of U.S. hospital systems, professional groups, and health advocates, including the American Cancer Society, also endorse routine testing. Most U.S. insurers, private and public, will cover the tests, which Medicare reimburses for $175, although tests may cost more depending on how many variants they screen for.

In its latest guidelines on colon cancer, the Cancer Network panel noted that not everyone with a risky gene variant gets sick from the drug, and that lower dosing for patients carrying such a variant could rob them of a cure or remission. Many doctors on the panel, including the University of Colorado oncologist Wells Messersmith, have said they have never witnessed a 5-FU death.

In European hospitals, the practice is to start patients with a half- or quarter-dose of 5-FU if tests show a patient is a poor metabolizer, then raise the dose if the patient responds well to the drug. Advocates for the approach say American oncology leaders are dragging their feet unnecessarily, and harming people in the process.

“I think it’s the intransigence of people sitting on these panels, the mindset of ‘We are oncologists, drugs are our tools, we don’t want to go looking for reasons not to use our tools,’” said Gabriel Brooks, an oncologist and researcher at the Dartmouth Cancer Center.

Oncologists are accustomed to chemotherapy’s toxicity and tend to have a “no pain, no gain” attitude, he said. 5-FU has been in use since the 1950s.

Yet “anybody who’s had a patient die like this will want to test everyone,” said Robert Diasio of the Mayo Clinic, who helped carry out major studies of the genetic deficiency in 1988.

Oncologists often deploy genetic tests to match tumors in cancer patients with the expensive drugs used to shrink them. But the same can’t always be said for gene tests aimed at improving safety, said Mark Fleury, policy director at the American Cancer Society’s Cancer Action Network.

When a test can show whether a new drug is appropriate, “there are a lot more forces aligned to ensure that testing is done,” he said. “The same stakeholders and forces are not involved” with a generic like 5-FU, first approved in 1962, and costing roughly $17 for a month’s treatment.

Oncology is not the only area in medicine in which scientific advances, many of them taxpayer-funded, lag in implementation. For instance, few cardiologists test patients before they go on Plavix, a brand name for the anti-blood-clotting agent clopidogrel, although it doesn’t prevent blood clots as it’s supposed to in a quarter of the 4 million Americans prescribed it each year. In 2021, the state of Hawaii won an $834 million judgment from drugmakers it accused of falsely advertising the drug as safe and effective for Native Hawaiians, more than half of whom lack the main enzyme to process clopidogrel.

The fluoropyrimidine enzyme deficiency numbers are smaller — and people with the deficiency aren’t at severe risk if they use topical cream forms of the drug for skin cancers. Yet even a single miserable, medically caused death was meaningful to the Dana-Farber Cancer Institute, where Carol Rosen was among more than 1,000 patients treated with fluoropyrimidine in 2021.

Her daughter was grief-stricken and furious after Rosen’s death. “I wanted to sue the hospital. I wanted to sue the oncologist,” Murray said. “But I realized that wasn’t what my mom would want.”

Instead, she wrote Dana-Farber’s chief quality officer, Joe Jacobson, urging routine testing. He responded the same day, and the hospital quickly adopted a testing system that now covers more than 90% of prospective fluoropyrimidine patients. About 50 patients with risky variants were detected in the first 10 months, Jacobson said.

Dana-Farber uses a Mayo Clinic test that searches for eight potentially dangerous variants of the relevant gene. Veterans Affairs hospitals use a 11-variant test, while most others check for only four variants.

Different Tests May Be Needed for Different Ancestries

The more variants a test screens for, the better the chance of finding rarer gene forms in ethnically diverse populations. For example, different variants are responsible for the worst deficiencies in people of African and European ancestry, respectively. There are tests that scan for hundreds of variants that might slow metabolism of the drug, but they take longer and cost more.

These are bitter facts for Scott Kapoor, a Toronto-area emergency room physician whose brother, Anil Kapoor, died in February 2023 of 5-FU poisoning.

Anil Kapoor was a well-known urologist and surgeon, an outgoing speaker, researcher, clinician, and irreverent friend whose funeral drew hundreds. His death at age 58, only weeks after he was diagnosed with stage 4 colon cancer, stunned and infuriated his family.

In Ontario, where Kapoor was treated, the health system had just begun testing for four gene variants discovered in studies of mostly European populations. Anil Kapoor and his siblings, the Canadian-born children of Indian immigrants, carry a gene form that’s apparently associated with South Asian ancestry.

Scott Kapoor supports broader testing for the defect — only about half of Toronto’s inhabitants are of European descent — and argues that an antidote to fluoropyrimidine poisoning, approved by the FDA in 2015, should be on hand. However, it works only for a few days after ingestion of the drug and definitive symptoms often take longer to emerge.

Most importantly, he said, patients must be aware of the risk. “You tell them, ‘I am going to give you a drug with a 1 in 1,000 chance of killing you. You can take this test. Most patients would be, ‘I want to get that test and I’ll pay for it,’ or they’d just say, ‘Cut the dose in half.’”

Alan Venook, the University of California-San Francisco oncologist who co-chairs the panel that sets guidelines for colorectal cancers at the National Comprehensive Cancer Network, has led resistance to mandatory testing because the answers provided by the test, in his view, are often murky and could lead to undertreatment.

“If one patient is not cured, then you giveth and you taketh away,” he said. “Maybe you took it away by not giving adequate treatment.”

Instead of testing and potentially cutting a first dose of curative therapy, “I err on the latter, acknowledging they will get sick,” he said. About 25 years ago, one of his patients died of 5-FU toxicity and “I regret that dearly,” he said. “But unhelpful information may lead us in the wrong direction.”

In September, seven months after his brother’s death, Kapoor was boarding a cruise ship on the Tyrrhenian Sea near Rome when he happened to meet a woman whose husband, Atlanta municipal judge Gary Markwell, had died the year before after taking a single 5-FU dose at age 77.

“I was like … that’s exactly what happened to my brother.”

Murray senses momentum toward mandatory testing. In 2022, the Oregon Health & Science University paid $1 million to settle a suit after an overdose death.

“What’s going to break that barrier is the lawsuits, and the big institutions like Dana-Farber who are implementing programs and seeing them succeed,” she said. “I think providers are going to feel kind of bullied into a corner. They’re going to continue to hear from families and they are going to have to do something about it.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.

Subscribe to KFF Health News’ free Morning Briefing.