Transcript for Two patients question their troubling Theranos test results: Part 6
Do you swear to tell the whole truth? I do. There's no better story than the young woman at Stanford who dropped out because she wanted to save people's lives. Once touted as silicon valley's sweetheart. If they have the ability to test people's blood right in the store, this could be the holy grail. If you could take a blood test -- One drop? One drop. Did Ms. Holmes know theranos couldn't do that? She knew. There's a part of me that still has fear. Everyone that invested lost it all. Send me my $100,000 back please. There's this argument she's trying to change the world and it's not easy to change the world. Should someone go to jail for this? Orange is the new black. Reporter: After 10 years in silicon valley, Elizabeth Holmes seemed unstoppable. Walgreens boots that's the largest they have decided that your way is the way to go. Reporter: She now envisioned a nationwide takeover. Access for every person means rolling this out ultimately within five miles of every person's home. Reporter: That would give millions of people access to her so called revolutionary technology. When will I have that opportunity to use a small test like that and find out data for myself? Working on it as fast as we I can tell you our next states are underway. Reporter: As theranos began building its wellness centers in Walgreens, the first major expansion was Arizona. I first was diagnosed with breast cancer back in 2013. I would get a sharp pain in my left breast. I'd gotten pretty thin, everybody was worried and boom there was a tumor. Reporter: Sheri Ackert, a wife and grandmother, was 57 years old when she began the fight of her life. I had the bilateral mastectomy in the beginning of reconstruction. I had four months of chemotherapy. I managed well through the treatments and I just kind of went back to life, kind of my new normal. Reporter: That new normal meant getting her blood drawn regularly to make sure she remained cancer-free. So my ob-gyn said do you want to try one of the theranos labs? I said hey, yeah let's try it. I think Walgreens has a great reputation. They're willing to bring theranos in. They must be okay. This is where I had the infamous blood draw. They seemed to know what they were doing and that was that. Reporter: But things took a terrifying turn when Sheri got her results. I will never forget that day and I saw that the estrogen amount was over 300. I also called my oncologist's office and the nurse called me back and she said I'm so sorry. That's not good. There could be a tumor growing somewhere. Reporter: The doctor told Sheri to go in for more tests, but this time recommended a nontheranos lab. It was about a week later I got the call from my doctor and he said congratulations your estrogen is basically nonexistent. Reporter: No new tumor, no new cancer. The theranos tests had been off by hundreds of points. Sheri says she tried to reach out to the company for answers, but didn't get a response. No one from theranos ever called me to apologize. That's the least you can do when you mess up so badly. Not okay. Reporter: It turns out this wasn't an isolated incident. Back in Palo alto, theranos had caught the attention of healthcare entrepreneur pallav Sharda. Pallav, a husband and father, with a family history of diabetes, had recently upended his life when his doctor had warned him to make some serious changes. Reporter: So you completely changed your lifestyle. Completely changed it. So I gave it three years. I could barely run a mile and a half. And in those three years, I became a guy who did 5ks every alternate day. Reporter: He wanted to be sure he was on the right track. Reporter: So you went to Walgreens to take this test. The first thing I noticed was the phlebotomist who was taking my blood, I asked her, "Well, wait. Wait a minute. This is supposed to be a pin prick." But she was doing a test tube draw in the usual way. It was a little red flag. I was, like, "Well, that's false marketing. Reporter: The theranos results indicated that he was prediabetic. But before starting on medication, he was advised to retake the same tests at a different lab. Within days the new results showed he was safely outside of the prediabetic range. Reporter: How did you feel when you saw this alternate outcome? Pissed. Like, I was -- this is not right. Like, you just can't lie. Can you guarantee nobody took an extra shot of insulin? Reporter: Overtime the complaints from customers started pouring in. But what these people didn't know was that employees on the inside had been having serious concerns too. It really ate me up inside. Reporter: Fresh out of Berkeley, Erika Cheung started working in the lab that processed patients samples. And she says she almost immediately noticed an intense culture of secrecy. They would barricade certain portions of the lab so you couldn't see. When outside vendors would come in, like they always had to be escorted by security. Reporter: At what point do you start to say something isn't right here? I think the transition happened when I started processing patient samples. Reporter: So you basically start out with a base test. Yes. Reporter: You put that base test in your machine just to say okay, we know it's working. We know it's cleared. Exactly. Reporter: And what happened? And it kept failing and I kept running it over and over. And how it was handled totally blew me away. They took out data points and said, oh well this is the best two out of six, the way we average things. Reporter: So you're saying essentially that you were cherry picking. Exactly. Reporter: The information in order to make the information make sense. But the thing is we were still processing patients. Reporter: Meaning those patients were taking information that you were providing to them and making medical decisions. Yes. Our quality controls were failing, at one point what seemed almost everyday. Reporter: When Erika says she raised these issues directly with sunny balwani, theranos' president and coo, she says he would become enraged. He had asked me so how do you like working for this company? And I said I really enjoy working for this company, but there are a lot of problems. We're having a lot of issues with our quality controls. And then he just sort of lost it at that point and he said I'm tired of people coming in here and starting fires where there are no fires. Reporter: Erika and others say Elizabeth and theranos ignored the warning signals from their own people and forged ahead. We've been able to serve a huge number of people in the last year and it has been phenomenal. There is no doubt in my mind that she knew she was crossing that line when she went live with the fingertip tests. Did Ms. Holmes know that theranos could not do all those tests? Yeah, she knew.
This transcript has been automatically generated and may not be 100% accurate.