Quest Diagnostics told the SEC on Oct. 22 2026 that it learned of unauthorized access to its Quanum Lab Services Manager on Oct. 21. Quanum LSM is the system some of Quest's clients use to place test orders and look up results. Quest says an unauthorized party accessed certain patient records, and that the full scope is still under investigation.
What Quest has confirmed
Quest's incident notice says protected health information and personally identifiable information are involved. It has not yet said which data.
It has notified federal law enforcement and brought in outside cybersecurity experts.
It paused access to Quanum LSM, and as a precaution paused two other tools, Essential Insights and LabHQ. Quest says data in those two was not accessed.
Quest says the incident is not related to the recent PHP vulnerability.
What Quest has not said
How many patients are affected.
Which records were taken, or how the intruder got in.
When notices will go out. The notice gives no timeline.
Quest's side: it says core business operations are not affected, and its SEC filing says the incident has not materially disrupted its business or its ability to serve patients.
What you can do this week
Watch your mail and patient portal. Quest says it will notify affected patients, providers and health plans as required by law. Its letters are to describe resources such as credit and identity monitoring. The notice does not say whether that monitoring is free, so read the letter before you sign up.
Ask your doctor's office whether it orders labs through Quanum LSM. Quest says only some clients use it, so a Quest test does not by itself mean your record was in this system.
Freeze your credit. The FTC says a credit freeze is free to place and lift and does not affect your credit score. Friday's issue walks through it step by step.
Up next · Wednesday
The prescription-history report insurers can pull when you apply for coverage, and how to ask for your copy.