The 8-year-old child presented to the emergency department with bilateral ankle pain that had progressively worsened over the past 24 hours. This morning he would not walk. He also had a rash on his legs. The astute ED doctor recognized the diagnosis as Henoch-Schönlein purpura (HSP) and arranged admission to the ward. Things were flowing smoothly that day, and the child was soon on the ward and being examined by me and the resident team during morning rounds. In that 45-minute gap, the father had been on his smartphone. At that point he knew more about HSP than my senior resident. Truth be told, I was glad I had treated two cases in the previous 3 months (after going more than 2 years without any cases) so I didn’t feel foolish myself.

Technology is making progressively larger amounts of medical information available to the lay public. That information is being organized in ways that can actually impart knowledge. The Wikipedia entry on HSP has far more information, and has it arranged in a much more useful fashion, than my textbook on pediatrics. Making that comparison was the first time in 5 years that the textbook has even been taken off the shelf. If you have Googled tonsillitis , sprained ankle, or measles in the past 2 months, instead of just a list of websites, you also would have seen half the page filled with images and vetted information about those illnesses. There are apps that help you create a differential diagnosis and even estimate the probabilities of each one.

Watson’s victory on Jeopardy showed how information can be organized and retrieved by a computer. It is a good facsimile for knowledge. But what about the wisdom of clinical judgment? Can a computer replace that? Keith Rabois , a member of the PayPal mafia , recently predicted that it will.

Further progress toward replacing doctors has come through changes in legislation to permit all lab tests to be offered directly to consumers. Arizona’s governor signed a law in April 2015 that will change that policy for his state. This isn’t major news, because already more than half the states allow this direct to consumer approach. But what was special about this particular signing ceremony was the involvement of billionaire Elizabeth Holmes, CEO of Theranos, a start-up company prepared to provide the lab testing service.

If done without a doctor’s order, which documents medical necessity, under current practice rules an insurance company won’t pay for these direct to consumer tests. The consumer must pay out of pocket. Of course, those rules may change. If patients want a throat swab to test for strep, maybe it is cheaper to have them go directly to the neighborhood lab than to see a doctor, especially if, when the test is positive, they then expect to phone their doctor for free and get a prescription.

Most medical tests have significant false-positive and false-negative results. Simple rapid strep throat tests and rapid influenza nasal swabs have a sensitivity of only 90%-95%. Many doctors, even those who use the results on a daily basis, cannot convert that information into a positive and negative predictive value. So if a company offers the test directly to the consumer, and reports it out with a “Just the facts, Ma’am” positive or negative result, is the consumer responsible for any misinterpretation, or has the laboratory company deceptively marketed a defective, imperfect product?

The bigger financial impact will be all the follow-up labs and imaging tests generated by the initial false-positive screening labs. Insurance probably will pay for those. Using a similar business model, a few hospitals nationwide now offer free (or close to it) low-dose chest CT scans to smokers and ex- smokers . This is done as a loss leader that generates profits for the hospital from all the follow-up tests, imaging, and biopsies. Compare this model with the old-time practice in which pediatricians in the 1950s to 1980s (and in many places, against guidelines, in the 1990s) had parents bring in a sample of the child’s urine for each well-child visit. That practice was abandoned on cost-benefit-harm arguments because of all the unnecessary subsequent testing, especially kidney ultrasounds, generated by the false positives. Now parents will be able to order the test themselves.

I’m skeptical about how soon a computer will completely replace a physician. Peter Thiel said, “We were promised flying cars and instead what we got was 140 characters.” But Google has finally created the self-driving car. And Elizabeth Holmes has averaged making more money in a week than I will in a career. So who are you going to believe?

Dr. Powell is a pediatric hospitalist and clinical ethics consultant living in St. Louis. E-mail him at .