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Elizabeth Holmes- Case Archive
personpersonErika CheungErika CheungFormer Theranos laboratory associate who worked in assay development and clinical testing.← All People
WitnessTheranos

Erika Cheung

Former Theranos laboratory associate who worked in assay development and clinical testing.

AppearedFederal Criminal Trial
1,401 lines·37 proceedings·29 mentions

About

Erika Cheung testified for the prosecution about her work in Theranos research and development and its clinical laboratory from October 2013 until approximately April 2014. She described Edison devices as processing one assay for one patient at a time and supporting a limited menu of tests, while the laboratory also relied on modified third-party analyzers, conventional equipment, and outside laboratories.

Her direct examination addressed continuing Edison validation, recurring quality-control failures, differences between written procedures and laboratory practice, manual removal of data points, device variability, and proficiency testing. Cheung testified that predicate-method results rather than Edison-generated results were provided to regulators during her tenure. She also described raising concerns with laboratory and company leaders, declining to process a hepatitis C sample on Edison because of reagent-stability concerns, leaving after Balwani questioned her qualifications and directed her to process samples without question, and later reporting concerns to CMS. An email to Holmes was admitted only to show notice, not for the truth of its contents.

On cross-examination, the defense tested the scope of Cheung's expertise and personal knowledge. She acknowledged that she largely ran experiments and compiled data for others to analyze, and that she lacked familiarity with several regulatory standards, policies, documents, and company initiatives. She also agreed that quality-control materials were not patient samples, calibration and bias correction were ordinary laboratory activities, and unresolved failures prevented patient results from being released. Cheung nevertheless maintained that actual practices sometimes differed from written procedures and disagreed with management's account that the written procedure had been followed during the November 2013 vitamin D incident.

On redirect, Cheung explained that validation was followed by continuing quality-control monitoring. She testified that recurring failures could require recalibration, occupy laboratory personnel around the clock, and delay patient results, and she described Edison processing as a multistep workflow rather than a minimally trained, highly automated process.

Trial Record (37)

FederalFederal Criminal TrialAug 31, 2021 – Jan 3, 2022Called by prosecution

Erika Cheung testified for the prosecution about Theranos laboratory operations, Edison's limited testing capability, recurring quality-control problems, proficiency testing, and her escalation of concerns. Cross-examination challenged the scope of her expertise and personal knowledge, while redirect clarified the continuing role of quality control after validation.

Jury Selection Day 1

sidebarSidebar on Cause and Hardship ChallengesMentioned

Summary

The court resolved several cause and hardship challenges involving media exposure, bias, caregiving, language, and learning concerns, while leaving three prospective jurors for further inquiry.

Mentioned in this proceeding.

Day 4

OpeningOpening Statement by the ProsecutionRobert S. LeachMentioned

Summary

The prosecution alleged that Elizabeth Holmes and Ramesh Balwani defrauded Theranos investors and patients through misrepresentations about the company's technology, partnerships, finances, retail rollout, and test accuracy. It previewed insiders, investors, patients, outside organizations, and records that it expected would support the wire-fraud and conspiracy charges.

Mentioned in this proceeding.

Day 6

ProceduralWitness Immunity Application and RulingMentioned

Summary

The court approved the government's immunity application for Surekha Gangakhedkar after prosecutors said her counsel indicated she would invoke the Fifth Amendment and the defense took no position.

Mentioned in this proceeding.

DirectErika Cheung — DirectErika CheungJohn C. Bostic1highlight160lines spoken

Summary

Erika Cheung described Edison limitations, Theranos's reliance on third-party analyzers and outsourced testing, ongoing assay validation, and discrepancies she observed in her own vitamin D results.

Highlights (1)

Quote“THE EDISON DEVICE COULD ONLY RUN ONE TYPE OF TEST FOR ONE PATIENT AT A GIVEN TIME.”— Erika CheungThe testimony sharply defined the operational capacity of the Theranos-built analyzer.Open in transcript →
ProceduralEmail Exhibit Admissibility HearingMentioned

Summary

Defense challenged Theranos email exhibits on hearsay, foundation, and relevance grounds; the court allowed foundation for Exhibits 1287 and 1289 and deferred the remaining dispute.

Mentioned in this proceeding.

Day 7

DirectErika Cheung — DirectErika CheungJohn C. Bostic7highlights378lines spoken

Summary

Cheung described recurring Edison QC failures, manual outlier removal, disparities in proficiency testing, internal warnings, and her eventual decision to leave Theranos and report concerns externally.

Highlights (7)

testimony highlightCheung testified that Theranos frequently removed two of six generated data points without a defined outlier protocol, which could make QC or validation data appear better.Open in transcript →
Quote“SO IT -- THERE WAS NO STANDARD PROTOCOL AT THERANOS FOR WHAT OUTLIER DELETION WAS. IT WAS SOMETHING THAT WAS CONDUCTED QUITE FREQUENTLY, AND IN NORMAL SENSE THIS WOULD BE CONSIDERED CHERRY PICKING, WHERE YOU'RE ESSENTIALLY PICKING THE BEST DATA POINTS TO MAKE IT APPEAR THAT THE QUALITY OF THE DATA IS BETTER THAN IT IS.”— Erika CheungCheung characterized Theranos's outlier-removal practice and explained why she believed it overstated data quality.Open in transcript →
Quote“IT HAD VERY POOR PERFORMANCE. WE WERE HAVING QC FAILURES AT A MAXIMUM EVERY THREE DAYS, POSSIBLY MORE.”— Erika CheungCheung gave a memorable assessment of the frequency and quality of Edison QC performance.Open in transcript →
testimony highlightComparative proficiency-testing data showed disparities between Edison and predicate-device results, including inconsistent Edison reruns; Cheung testified that Edison-generated proficiency results had not been provided to regulators during her employment.Open in transcript →
Show all 7 highlights
Quote“AT MY TIME AT THERANOS WE DID NOT PROVIDE REGULATORS WITH THE RESULTS GENERATED FROM THE THERANOS EDISON DEVICES SIMPLY FROM THE PREDICATE METHOD. SO THIS INFORMATION WAS NOT PROVIDED TO REGULATORS.”— Erika CheungCheung testified from her involvement in proficiency testing about which results were provided to regulators during her employment.Open in transcript →
testimony highlightMarch 2014 data showed a 25.6 percent overall Edison QC-run failure rate, which Cheung described as typical rather than an unusually bad month; she contrasted that with rare QC failures on third-party devices.Open in transcript →
emotional momentCheung described becoming stressed and uncomfortable while patient testing continued, reporting her concerns to Sunny Balwani, receiving a response that questioned her qualifications, and leaving Theranos around the time of that meeting.Open in transcript →
CrossErika Cheung — CrossErika CheungLance A. Wade1highlight402lines spoken

Summary

Defense counsel emphasized Theranos's trained laboratory teams, formal validation reports, multiple approvals, and written operating procedures while narrowing Cheung's personal expertise. Cheung agreed that QC preceded patient testing but maintained that validation was sometimes compressed, written procedures differed from practice, and frequent reader failures required extensive recalibration.

Highlights (1)

Quote“BUT AT THERANOS WE WERE RUNNING THEM IN A SHORTENED TIMEFRAME, SO WE WOULD JUST TRY AND GET THEM DONE AS SOON AS POSSIBLE. SO IT WOULD BE LIKE THREE DAYS TO A WEEK AND A HALF.”— Erika CheungAlthough the defense emphasized the amount of validation work, Cheung testified that Theranos compressed a process she said would usually take about three months.Open in transcript →

Day 8

CrossErika Cheung — CrossErika CheungLance A. Wade3highlights322lines spoken

Summary

Defense counsel used laboratory procedures, email chains, workflow improvements, and a sample-volume patent to emphasize Theranos's monitoring and remediation systems and to narrow Cheung's expertise. Cheung nevertheless maintained that the vitamin D SOP was not followed, confirmed that hepatitis C was not run on Edison after her concerns, and described Edison as a one-patient, one-test device.

Highlights (3)

confrontationCheung maintained that the SOP had not been followed during the vitamin D quality-control episode, expressly disagreeing with Daniel Young and testifying that her group was not retrained afterward.Open in transcript →
Quote“I DISAGREED WITH MR. YOUNG.”— Erika CheungCheung preserved her disagreement with management's conclusion that the SOP had been followed during the vitamin D quality-control incident.Open in transcript →
evidence eventThe court admitted a Theranos sample-volume patent after the government stipulated to authenticity; Cheung identified the T-cup drawings but emphasized that the patent activity occurred after her employment.Open in transcript →
RedirectErika Cheung — RedirectErika CheungJohn C. Bostic4highlights70lines spoken

Summary

Cheung testified that Theranos compressed validation, offered few Edison fingerstick assays, and faced frequent QC failures that could delay patient results for days; she also contrasted her experience with Theranos system claims in Exhibit 9925.

Highlights (4)

testimony highlightCheung said ongoing QC was necessary after validation, placed her vitamin D accuracy concerns around November 2013, and described frequent recalibration episodes that could delay expected patient results by two or three days.Open in transcript →
Quote“SO IT ONLY ADDRESSED BASICALLY WHAT THE QUALITY OF IT WAS AT THE BEGINNING OF THE DAY.”— Erika CheungCheung explained the temporal limitation she perceived in Theranos's once-daily quality-control practice.Open in transcript →
Quote“JUST BECAUSE THEY'RE LESS -- YOU SHOULDN'T -- JUST BECAUSE THEY'RE LESS EXPENSIVE DOESN'T MEAN THAT YOU SHOULD GIVE SOMEONE FALSE INFORMATION ABOUT THEIR HEALTH STATUS. YEAH, SO YOU SHOULD BE ABLE -- IF YOU ARE PROVIDING LAB TESTING SERVICES FOR A PATIENT, IT STILL SHOULD BE OF A QUALITY STANDARD THAT THEY CAN HAVE SOME CONFIDENCE THAT THERE IS ACCURACY TO THE RESULT THAT THEY'RE RECEIVING. IT SHOULDN'T BE THE CASE THAT BECAUSE YOU PAY LESS THIS MEANS THAT YOU GET A LESS QUALITY RESULT.”— Erika CheungCheung rejected price as a reason to accept reduced confidence in patient-test accuracy.Open in transcript →
emotional momentCheung explained that she did not return post-employment calls after hearing fear in an HR employee's voice because it reminded her of her own fear while working at Theranos.Open in transcript →

Day 9

ProceduralEvidentiary HearingMentioned

Summary

The court set an initial protocol for displaying selected Holmes-Balwani messages, confirmed limits on customer-impact testimony, and addressed corrected test reports without deciding all message-specific objections.

Mentioned in this proceeding.

Day 10

ProceduralText Message Admissibility Hearing and RulingsMentioned

Summary

The court resolved disputed Rule 106 text-message designations, allowed journalist-related messages for notice and knowledge with a limiting instruction, ordered one name redacted, and left other evidentiary objections open.

Mentioned in this proceeding.

Day 11

Day 13

CrossAdam Rosendorff — CrossAdam RosendorffLance A. WadeMentioned

Summary

Defense counsel challenged Adam Rosendorff with inspection records, compliance emails, signed Edison validation reports, quality-system data, and proficiency-testing records. Rosendorff acknowledged inspection cooperation, assay approvals, and predicate-device proficiency testing while maintaining that later Edison performance, incident management, and alternative testing remained deficient.

Mentioned in this proceeding.

Day 14

CrossAdam Rosendorff — CrossAdam RosendorffLance A. WadeMentioned

Summary

Defense counsel challenged Adam Rosendorff with AAP policies, laboratory emails, physician-call records, and meeting calendars. Rosendorff accepted substantial laboratory-director responsibility but maintained that proficiency-testing implementation and data access were incomplete and that management sometimes exceeded its qualifications.

Mentioned in this proceeding.

Day 16

RecrossAdam Rosendorff — RecrossAdam RosendorffLance A. WadeMentioned

Summary

Defense counsel used emails and prior testimony to challenge Adam Rosendorff on laboratory authority, HCG implementation, launch scope, and complaint frequency. Rosendorff made several concessions but preserved qualifications about operational control, quality-control failures, and limited recollection.

Mentioned in this proceeding.

Day 19

Day 31

Day 36

ProceduralRule 29 Motion and Evidentiary Record MattersMentioned

Summary

The defense renewed challenges to the CMS report, Erin Tompkins's HIV-result evidence, and evidence affected by the unavailable LIS database. Holmes also made a Rule 29 motion, which the court took under submission, and the court limited the defense's patent summary to applications filed through 2016 before the defense called Trent Middleton.

Mentioned in this proceeding.

Day 39

DirectElizabeth A. Holmes — DirectElizabeth A. HolmesKevin M. DowneyMentioned

Summary

Holmes described Theranos's military projects, demonstrations, laboratory oversight, and regulatory history before giving emotional testimony alleging coercion and sexual abuse by Ramesh Balwani. She denied that Balwani forced her investor or press statements, addressed the 2015 CMS failures and later remediation, and said she never sold her Theranos shares.

Mentioned in this proceeding.

Day 40

CrossElizabeth A. Holmes — CrossElizabeth A. HolmesRobert S. LeachMentioned

Summary

Holmes's cross-examination covered Theranos's response to critical reporting and whistleblowers, her control of the company, limits on Theranos devices, and Balwani's influence. She acknowledged major mistakes in the Wall Street Journal response, extensive reliance on commercial equipment, and problems with pharmaceutical-branded reports while disputing retaliation and several prosecutorial characterizations.

Mentioned in this proceeding.

Day 42

RedirectElizabeth A. Holmes — RedirectElizabeth A. HolmesKevin M. DowneyMentioned

Summary

Holmes used redirect to explain Theranos's laboratory oversight, modified analyzers, financial projections, partner reports, trade-secret restrictions, and responses to Tyler Shultz. She attributed operational and technical work to others while acknowledging authority over investor presentations and explaining nondisclosure of modified systems as trade-secret protection.

Mentioned in this proceeding.

Day 45

Day 46

ClosingClosing Argument by the ProsecutionJeff SchenkMentioned

Summary

The prosecution argued that Holmes knowingly deceived investors and patients, linked the documentary and testimonial record to the conspiracy and wire-fraud elements, rebutted the principal defense themes, and requested guilty verdicts on all remaining counts.

Mentioned in this proceeding.

Day 47