There’s a warning out today for those who go online or to apps to figure out why they have an upset tummy or nagging cough or occasional chest pain. Symptom checkers, those tools that ask for information and suggest a diagnosis, are accurate only about half of the time.

The finding is from a Harvard Medical School study that reviewed 23 sites, such as WebMD, the Mayo Clinic and DocResponse. One third listed the correct diagnosis as the first option for patients. Half the sites had the right diagnosis among their top three results, and 58 percent listed it in their top 20 suggestions.

Dr. Ateev Mehrotra, one of the study’s authors, urges patients to be cautious when using these tools.

“These sites are not a replacement for going to the doctor and getting a full evaluation and diagnosis,” he says. “They are simply providing some information on what might be going on with you.”

About a third of U.S. adults use the sites, although not necessarily in place of going to the doctor.

Some of the diagnostic questions are also used by nurse triage phone services and,

Mehrotra says, these online tools are about as accurate as the call-in lines offered by many insurers and physician groups. “[They are] better than just a random Internet search,” he said.

Researchers entered the symptoms of 45 patients from vignettes used to train medical students. The Mayo Clinic’s first online diagnosis was right only 17 percent of the time, but had the correct diagnosis on a list of 20 in 76 percent of cases.  Dr. John Wilkinson, who works on Mayo’s symptom checker, says the tool directs patients to medical research and prepares them to talk to their doctor.

“We’re always trying to improve but if most of the time the correct diagnosis is included in the list of possibilities, that’s all we’re attempting to do,” he says.

The diagnosis accuracy rate for physicians is 85 to 90 percent. But Jason Maude, who runs a high performing tool called Isabel, says he does not want a Web versus doctor showdown.

“The whole point is not to set the patient against the doctor or replace the doctor, but to make the patient much better informed and to ask the doctor much better questions, and then together they should do a much better job,” he says.

Isabel ranked well in the study, showing the correct answer more than 40 percent of the time in the first diagnosis and 84 percent in the top 20 answers. Those high results, Maude says, may be because the site lets patients type in their own description of symptoms. They might describe a “tummy ache” or “stomach cramps” rather than the more clinical choice of “abdominal pain” used by many online symptom checker tools. And Isabel asks just two or three questions before patients describe their problem, as compared to sites that ask patients to click through 20 questions — steps Maude said may discourage use.

Clarifying how and why patients use these tools is critical, say the study’s authors. They could reduce unnecessary office visits or inform patients as they talk with their doctors.  But for some, the tools may encourage people to seek unnecessary care.

Mehrotra says patients used symptom checkers more than 100 million times last year, a fact that may stun some physicians.

“While most doctors know patients are going to the Internet to search for medical advice, in terms of these symptom checkers, I’ve been surprised that few of my colleagues even knew they existed,” he says.

This story is part of a reporting partnership with NPR, WBUR and Kaiser Health News.

Kaiser Health News (KHN) is a national health policy news service. It is an editorially independent program of the Henry J. Kaiser Family Foundation.

During the past few years, Oregon has quietly become a prime location for women willing to carry children for those unable to get pregnant. There are several reasons for that: lenient laws, a critical mass of successful fertility clinics and a system for amending a birth certificate pre-birth.

But surrogacy arrangements are often informal agreements, and they can go wrong. A surrogate may face unexpected medical bills, or the intended parents may change their mind.

Yet Mardi Palan is excited about becoming a surrogate, and that’s due in part to a very thorough contract she has signed governing the terms of her surrogacy. It includes Palan’s compensation, standards she must meet and a wide array of protections for her. “The contract needs to be black and white, because there has to be some clarity at one point in the process regarding expectations,” said John Chally, the director of the NorthwestSurrogacy Center in Portland, where Palan signed up.

Palan is 30 and a hair stylist. She hopes to carry twins for a gay couple from Israel. She has a partner and a 1½-year-old son.

“I carried my son really well, and I really enjoyed being pregnant,” she says. “People mentioned surrogacy as an option to make money on the side and do something really nice for someone else.”

Palan’s contract covers what’s expected of her and a multitude of contingencies. The basics are that Palan will get about $25,000 if she successfully delivers one child, and an additional $5,000 for twins. She says she’ll use it for a down payment on a home.

The contract also deals with ethical issues. It states, for example, that Palan is not selling the children, nor agreeing to terminate her parental rights. That is because none of her genetic material is involved in the pregnancy. The two eggs will come from a donor, and the sperm will come from the two fathers in Israel.

“The analogy is that I’m the soil and someone else is the seed and someone else is the water, so we come together to make the child,” she says.

The contract says Palan is getting paid for “services rendered” and compensation for any pain and emotional distress she may suffer.

Palan’s lawyer, Marlene Findling, says it’s a good contract. “By far the vast majority of these contracts go really smoothly. This contract does protect her.”

And there’s a lot at stake. The intended parents are paying more than $100,000 for their child, or children.

Doctors will get about $45,000.

The NW Surrogacy Center will get about $23,000.

Chally wrote the contract. He says he’s tried to include every possible situation, even if it seems painfully direct — like when it says Palan will get $2,500 if she loses her uterus.

But, he adds, “As with most of those things, those contracts don’t describe relationships between people.”

Chally says he works hard to make sure surrogates aren’t turned into commodities. That takes a lot of work, because 70 percent of Chally’s clients come from `. He has worked with people from 23 countries.

Palan went out to breakfast and dinner with the couple from Israel. She was worried they wouldn’t like her tattoos, rainbow hair or nose stud. But they’re artists, and she says they took her appearance in stride.

Chally says it’s critical for surrogates to get along with prospective parents. He’s turned away unsociable couples seeking a surrogate.

“Surrogates want to know who [the parents] are,” he says. “They want to know what kind of relationship the two of them have. They want to see the joy in their eyes about realizing that there’s a pregnancy. They frankly want some time and attention during that process, as a manifestation of their care and concern for her, as she’s doing a truly remarkable thing for them.”

The contract goes on to stipulate Palan’s behavior with requirements designed to help keep the fetus from harm.

For example, she’s subject to random drug, alcohol and nicotine testing at a clinic. She can’t clean a litter box, get a tattoo or have an X-ray.

Another interesting clause in Palan’s contract is that she has agreed not to travel across the border to Washington during her pregnancy. Washington allows surrogacy for only a limited set of reasons, and surrogacy for financial gain is illegal there.

Sister Sharon Park, of the Washington State Catholic Conference, says, “The potential for exploitation of surrogates is huge, especially when money gets involved.”

For her part, Palan feels protected and empowered by the contract. She started hormone injections July 4 and expects to have two embryos implanted in August.

This story is part of a reporting partnership with NPR, Oregon Public Broadcasting and Kaiser Health News.

Kaiser Health News (KHN) is a national health policy news service. It is an editorially independent program of the Henry J. Kaiser Family Foundation.