The on-demand, ”Uber-for-X” fervor has produced an Uber for everything. There are Ubers for laundry, for groceries, for parking and massages. There is also, apparently, an Uber for blood.

That startup is Iggbo, and in December it raised $3.1 million in seed funding to provide blood draws via a “high-quality, on-demand, nationwide phlebotomy workforce.”

Here’s how it works: Iggbo collects lab test orders through its website from doctors and other medical providers. It then dispatches those orders to a network of Iggbo phlebotomists (there are currently about 8,000 of them across 100 cities), who meet patients at their homes or perhaps an office to draw their blood.

Iggbo says it’s solving two problems. First, it’s helping health-care providers who might not have the resources or infrastructure to conduct certain blood tests. Second, it’s making those medical services more accessible and convenient for patients. (Iggbo’s motto is “Stick With Us.”)

Like Uber, Iggbo is building its business on independent contractors, which is how it hires phlebotomists. The sales pitch to phlebotomists on Iggbo’s website includes “be your own boss” and “build your own future.” Contractors work when they want and are paid, on average, around $20 for each blood draw. “We are a technology company, and provide deal flow and processes and so forth for the labor force,” Nuno Valentine, Iggbo’s CEO, told Quartz. That is also very much like Uber, which you might recall is not a taxi company, but a technology company.

What a lot of these companies tend to realize too late is that the Uber model doesn’t really fit for them. Sometimes that’s because the service they’re selling is complicated (more so than driving a car), but they can’t really train workers who are contractors, as that’s typically considered indicative of an employer-employee relationship. Other times it’s because they can’t achieve the frequency and scale that both makes Uber viable financially and helps to ensure that enough people are always working on the platform, even though the contractors set their own hours.

Iggbo will probably realize this too, sooner or later. For example, Valentine says Iggbo gives phlebotomists specific instructions for each job and closely monitors their performance. ”We have 17 different metrics that we measure on quality on every transaction,” he says. “A lot of proprietary algorithms that we’ve created that ensure that the entire process from beginning to end occurs in the proper time, in the proper sequence. … We communicate all that through our technology.”

For Iggbo, though, such policies could be viewed as employer-like, and threaten its independent contractor model. (Again, whether or not a company provides training for their workers is viewed as an important test of whether those workers are “employees.”) Valentine says Iggbo doesn’t provide specialty training needed to become a phlebotomist, though it does provide information to workers on how to draw, package and send blood tests to labs.

Iggbo, of course, is only one company. But it’s worth watching as another test of whether the Uber-for-X model actually works.