Quest Diagnostics has disclosed a cyberattack involving unauthorized access to patient records, according to an October 22 SEC filing.
The company discovered the incident October 21 in its Quanum Lab Services Manager system, which healthcare providers use to order laboratory tests and access results.
Quest confirmed that personal information and protected health information were compromised but has not disclosed the number of affected patients or the specific records accessed. The Quanum platform is reportedly used by approximately 500,000 clinicians across thousands of locations in North America.
Quest suspended access to the affected system, notified federal law enforcement and engaged external cybersecurity experts.
Darin Fredde, Sr. Director of Technical Marketing Engineering, Ridge Security:
“I hate seeing incidents like this, especially in healthcare, where some of our most personal information is at stake. Quest’s containment efforts are an important first step, but containment isn’t the finish line. The real work is establishing how the attacker got in, what they could access, whether they left anything behind, and independently verifying that those paths are closed. We don’t yet know the full scope, and keeping operations running doesn’t necessarily mean patient information is safe. In healthcare, restoring service and restoring trust are two very different tests.”
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Seemant Sehgal, Founder & CEO, BreachLock:
“An attacker with read-level access to this system walked out with a current view of what conditions patients are being tested for and treated for across thousands of locations, but the provider side matters too. Physician names, NPIs, and ordering patterns give an attacker everything they need to run targeted phishing against the clinicians who ordered testing and diagnostics, and that could turn this breach into a staging ground for the next one.
“Breaches like this one sit in the same category as what we saw with Change Healthcare, where a single compromised vendor has reach into millions of records across downstream organizations that cannot easily switch providers.”
Another day, another company pwned. And I say it all the time which is that your company should not want to ever be the next victim. Thus you need to do everything possible to keep the bad guys out. And do it quickly.
Quest Diagnostics confirms patient health records compromised in cyberattack
Posted in Commentary with tags Hacked on October 23, 2026 by itnerdQuest Diagnostics has disclosed a cyberattack involving unauthorized access to patient records, according to an October 22 SEC filing.
The company discovered the incident October 21 in its Quanum Lab Services Manager system, which healthcare providers use to order laboratory tests and access results.
Quest confirmed that personal information and protected health information were compromised but has not disclosed the number of affected patients or the specific records accessed. The Quanum platform is reportedly used by approximately 500,000 clinicians across thousands of locations in North America.
Quest suspended access to the affected system, notified federal law enforcement and engaged external cybersecurity experts.
Darin Fredde, Sr. Director of Technical Marketing Engineering, Ridge Security:
“I hate seeing incidents like this, especially in healthcare, where some of our most personal information is at stake. Quest’s containment efforts are an important first step, but containment isn’t the finish line. The real work is establishing how the attacker got in, what they could access, whether they left anything behind, and independently verifying that those paths are closed. We don’t yet know the full scope, and keeping operations running doesn’t necessarily mean patient information is safe. In healthcare, restoring service and restoring trust are two very different tests.”
ㅤ
Seemant Sehgal, Founder & CEO, BreachLock:
“An attacker with read-level access to this system walked out with a current view of what conditions patients are being tested for and treated for across thousands of locations, but the provider side matters too. Physician names, NPIs, and ordering patterns give an attacker everything they need to run targeted phishing against the clinicians who ordered testing and diagnostics, and that could turn this breach into a staging ground for the next one.
“Breaches like this one sit in the same category as what we saw with Change Healthcare, where a single compromised vendor has reach into millions of records across downstream organizations that cannot easily switch providers.”
Another day, another company pwned. And I say it all the time which is that your company should not want to ever be the next victim. Thus you need to do everything possible to keep the bad guys out. And do it quickly.
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