Correction: A previous version of this article misstated the amount of the raise. It was $4 million.

Bivarus, a Durham, North Carolina-based company offering an algorithm-driven approach to patient feedback, has raised $4 million in second round funding. Hatteras Venture Partners led the round with additional participation from Excelerate Health Ventures, NueCura Partners, and Boston Millennia Partners -- all existing investors.

Founded in 2014, Bivarus's approach to patient feedback for providers is a reversal of the traditional approach, which gives a large number of questions to a few patients. Instead, Bivarus gives a small list of bespoke questions to all patients.

"We ask every patient that runs through your hospital for their feedback, but the questions that we ask to an individual patient are limited to 10 questions, and are dynamically and automatically selected from a pool of questions based on who the patient is, the service that was delivered to them, the relative importance, and everything we know about responses to that question up until that point," CEO David Levin told MobiHealthNews. "So if you had 100 patients discharged from your hospital, each of them might get a different set of 10 questions, and then we aggregate that data on the back end to give our customers a very rich look at all of their patients and all of the measures that they care about."

Patients are sent the questions by email or text message within 24 hours of thier visit.

"Our response rate is really strong," Levin said. "It depends on the clinical setting, but it ranges from 30 percent in the ER to 60-to-70 percent in an outpatient physician practice where there’s an established relationship between the practice and the patient."

Bivarus also acquired another company, the Jackson Group last year. The acquisition gave Bivarus the certifications and approval to participate in the CAHPS program, a CMS program that mandates certain kinds of patient feedback for Medicaid reimbursement.

The company currently has about 160 different customers, 50 percent of which are hospitals. The other half are large physician practices including Texas Oncology and Tennessee Oncology. In addition to the patient feedback product, Bivarus also offers a platforms for employee and community feedback.

The new funding round is primarily focused on scaling and expanding the program after significant growth last year (the company reports a 700 percent growth in revenue). It will also be used to launch a new version of the product, due out this summer, that gives doctors more visibility and control on the back end, Levin said.