Theranos director: Blood tester will be vindicated

The recent criticism surrounding Theranos, a privately held diagnostics company valued at about $9 billion, has been unfair, Theranos board member Richard Kovacevich said Monday.

He was responding to a series of Wall Street Journal reports raising questions about the accuracy of the proprietary method from Theranos — designed to conduct lab tests using only a small finger prick instead of drawing blood the traditional way with needles. The company stands by its claims, and CEO Elizabeth Holmes defended the work on CNBC in October.

Read MoreTheranos CEO fires back at WSJ: I was shocked

"I think it's very, very unfortunate what's happening to Theranos. I think it's very unfair. I believe in Elizabeth and what she's doing," Kovacevich told CNBC's "Squawk Box" on Monday. "I think time will tell that [Theranos] truly is revolutionizing the diagnostic business."

Kovacevich, former Wells Fargo chairman and CEO, is among the power players on the Theranos board, which also includes former Secretary of State Henry Kissinger, epidemiologist and ex-CDC Director William Foege, as well as former Senate Majority Leader Bill Frist, who is also a heart and lung transplant surgeon.

Addressing critics who claim there should be more board members from the medical field, Kovacevich said: "Most boards don't have scientists on them quite frankly. The scientists are internal and outside consultants." Though he did point to Frist, Foege, as well as mathematician and engineer William Perry who also served as defense secretary under President Bill Clinton, as examples.

Read MoreKovacevich warns market bubbles may burst in 2016

Touted as the world's youngest female billionaire, Holmes founded Palo Alto, California-based Theranos in 2003. She was just 19 years old. A year later, she dropped out of Stanford University. Holmes has raised more than $400 million in funding, and she owns 50 percent of the company.

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