The Silicon Valley company Theranos has an alternative—instead of a hypodermic needle and multiple vials of blood, Theranos technology uses a finger prick like the one diabetics use to measure their blood sugar. With just a few milliliters of blood Theranos can test for hundreds of things, from cancer biomarkers to cholesterol counts, illegal drugs to infectious diseases. What’s more, many of the tests are cheap. And in at least one state, the system doesn’t require a visit to a doctor’s office or a lab. But Theranos has been slow to deploy its system.

Now things are starting to pick up. On Thursday the US Department of Health and Human Services gave the company a Clinical Laboratory Improvement Amendments waiver1 for a single finger-prick blood test, for type 1 herpes simplex. But that CLIA waiver does much more than approve one test—it also covers Theranos’ complete system, hardware and software underpinning the entire diagnostic suite. That means that Theranos’ partners, places like Capital BlueCross, Amerihealth Caritas, and the Cleveland Clinic, can install Theranos tech in place instead of having to send samples back to the company’s Silicon Valley headquarters for testing.

And earlier in July, the FDA declared that same finger-prick herpes test was just as effective as the current version, the one with needles. Then Arizona made it legal to get a blood test without a doctor’s permission, on your own initiative.

Taken together, these developments mean Theranos is on its way to reinventing the field of clinical chemistry—that’s blood work. And that has some scientists worried. While Theranos has touted the fact that the FDA says its tests work as well as traditional diagnostics, the company hasn’t been forthcoming about how the tests work. So physicians are asking if it’s enough for Theranos to be cheaper and faster when they don’t know—can’t know—how the company gets its results.

Better, Faster Tests

Today two companies dominate the diagnostic blood test business: Quest Diagnostics and LabCorp. As far as price is concerned, Theranos is already winning. Quest and LabCorp tests can cost…well, that depends—on your hospital, your insurer, on the day of the week. Diagnostic tests—despite being pretty much the same everywhere—don’t have any official pricing. Many Theranos tests, on the other hand, cost less than $10, and the company posts its prices openly. Quest did not respond to requests for comment for this story, and LabCorp declined to comment altogether.

Theranos also wants to be fast. Like, wecantellyouifyouhaveherpesinamatterofhours fast. Back when anyone using a Theranos kit had to ship samples back to California for analysis, results were slow. Now that Theranos can distribute testing technology to all its partners, that’s fixed. Patients at any of Theranos’ partner institutions can walk in, get a finger-prick, and get their results.

In fact, pretty soon those patients might not even need a doctor’s note to get that test. Theranos’ CEO Elizabeth Holmes has repeatedly stated her desire to put blood tests into patients hands. The company declined to make her available for this story, but in 2014, she told WIRED:

There are a billion tests done every year in the United States, but too many of them are done in the emergency room. If you were able to do some of those tests before a person gets checked into the ER, you’d start to see problems earlier; you’d have time to intervene before a patient needed to go to the hospital. If you remove the biggest barriers to these tests, you’ll see them used in smarter ways.

That kind of access has already begun. In Arizona, a new law (co-authored by Theranos) cuts out the middle medic. People there can walk into a Walgreens—another Theranos partner—and get any of the tests the company offers, without a physician even knowing about it.

This doesn’t drive the medical community as insane as you’d think. “I’m in favor of open access for the patients themselves. Once available, the patient should not wonder about the results, if not have access to them,” says David Koch, a clinical pathologist at Emory University and president of the American Association of Clinical Chemistry. “The concern is that you need help in interpreting those results and knowing what to do next.”

Yes-or-no tests are great for finding out if you have herpes or your kid is on meth, but that can get a little trickier when you’re talking about more complex conditions. For example, if a man with prostate cancer has his prostate removed, his levels of Prostate-Specific Antigen should drop below detectability. If they come back, says Stephen Master, director of clinical chemistry at Cornell Weill Medical College, it signal that he has leftover prostate cells, and those may or may not be cancerous. “But all that depends on if you have a suitable baseline,” Master says. Establishing that baseline can be difficult, even for experienced physicians using established tests. All of which means that test results often require expertise to figure out their meaning.

I asked Theranos if the company had a plan to provide counseling or otherwise educate people who used their tests. A spokesperson responded by pointing me to this quote from this press release: “The Theranos model is physician-centric. Our goal in providing more accessible, less expensive, and less painful diagnostic tests is to enable individuals and physicians to better engage early when interventions can be most effective.”