Quest Diagnostics Confirms Patient Health Data Was Stolen: What US Patients Should Do

One of America’s largest medical testing companies has confirmed that patients’ personal and health information was stolen in a cyber attack. Quest Diagnostics, which processes lab tests for a huge share of US doctors and hospitals, says hackers accessed a system used to order tests and view results. The Quest Diagnostics breach is the latest in a wave of attacks on healthcare companies, and it is another reminder of how valuable a health data breach can be to criminals. Here is what Quest has confirmed and what patients should do now.

What Quest Has Confirmed

Quest says it learned of unauthorised access to its Quanum Lab Services Manager system on 21 October 2026. Some healthcare clients use the system to place test orders and to receive and look up results, the company said in a filing with the US Securities and Exchange Commission, as BleepingComputer reported.

In a notice on its website, Quest confirmed that some patients’ protected health information was taken, including personal information and patient records, according to TechCrunch. The company is still investigating which specific types of data were taken.

What is still unknown

Quest has not said how many patients or healthcare providers are affected, when the breach began, or whether any hacking group has made demands. It has notified law enforcement and brought in outside cyber security experts.

How Quest Responded

Quest activated its incident response plan to contain the activity and investigate. It paused access to the affected Quanum system and to some related tools, and suggested clients use paper forms or other ordering systems in the meantime. The company says the incident has not materially disrupted its business or its ability to serve patients.

Not Quest’s First Breach

This is not the first time Quest patients have been affected. In 2016, data including lab results for about 34,000 people was exposed. In 2019, personal information belonging to about 11.9 million Quest patients was exposed through an attack on a third-party billing company.

Healthcare has become a major target for criminals. Medical records are especially valuable because they combine identity details with sensitive health information that cannot be changed like a password.

What Patients Should Do Now

If you have had tests through Quest, take these steps:

• Watch for official notices. Quest says it is working to identify affected patients and providers. Legitimate letters should explain what was involved.
• Be alert to scams. Criminals often follow breaches with fake emails, texts and calls pretending to be from the company. Do not click links or share details without checking independently.
• Review medical and insurance statements. Look for tests, treatments or claims you do not recognise, which can signal medical identity theft.
• Consider a credit freeze if you are worried your identity details were exposed.
• Use strong, unique passwords on patient portals and turn on multi-factor authentication where available.

This week has seen several major breaches, including the Fortinet and Palo Alto firewall campaign and the Ogi “Password1” breach. Our how to protect yourself after a data breach guide covers more steps.

Health Data Needs Extra Care

The Quest breach shows how a single compromised system can expose sensitive health information at scale. Until the full picture emerges, patients should stay alert. Watch for official notices, ignore suspicious messages and check your medical statements carefully in the weeks ahead.

Frequently Asked Questions

How do I know if my data was affected?

Quest is still identifying affected patients. Watch for an official notice, and be cautious of unsolicited messages claiming to be from Quest.

What information was taken?

Quest says personal information and patient records were taken, but it is still determining the specific data types.

Is Quest still operating normally?

Quest says the incident has not materially disrupted its operations, though some systems were paused.

Has a hacking group claimed the attack?

Quest has not said whether any group has contacted it.