{"id":239571,"date":"2026-10-29T10:52:21","date_gmt":"2026-10-29T17:52:21","guid":{"rendered":"https:\/\/www.mcafee.com\/blogs\/?p=239571"},"modified":"2026-10-29T10:52:21","modified_gmt":"2026-10-29T17:52:21","slug":"quest-diagnostics-data-breach","status":"publish","type":"post","link":"https:\/\/www.mcafee.com\/blogs\/security-news\/quest-diagnostics-data-breach\/","title":{"rendered":"Quest Diagnostics Data Breach Exposes Patient Records: How to Stay Safe"},"content":{"rendered":"

Quest Diagnostics, one of the largest lab testing companies in the US, disclosed in an October 22, 2026, SEC filing<\/a> that an unauthorized party accessed certain patient records in its Quanum Lab Services Manager (LSM) system. The company’s Quanum security notice<\/a> says Quest believes protected health information and personal information were involved. The number of affected patients and the specific data taken have not been disclosed, and the investigation is ongoing.<\/p>\n

How the Quest Diagnostics Breach Happened and What Was Exposed<\/strong><\/h2>\n

The unauthorized access was discovered on October 21, 2026, according to Quest’s SEC filing. Doctors’ offices, health systems, and other Quest clients use Quanum LSM to place lab test orders and to receive and look up results. Patient data inside that system was accessed, the company says, but its other systems were not affected.<\/p>\n

According to the notice, the company believes both protected health information (PHI) and personally identifiable information (PII) were involved. Quest has not listed which specific data fields were exposed, and it has not disclosed how many patients were affected. The potential reach is wide: Quest says it serves about half of the physicians and hospitals in the US<\/a> and touches the lives of one in three American adults each year.<\/p>\n

To contain the breach, Quest paused access to Quanum LSM and, as a precaution, to its Essential Insights and LabHQ systems. Its notice says access to all three had been restored as of October 26. The SEC filing adds that Quest notified federal law enforcement and brought in outside cybersecurity experts. As of October 23, no hacking group had publicly claimed the attack. Quest is posting updates on its security notice at questdiagnostics.com\/links\/quanum-notice<\/a>.<\/p>\n

This is not Quest’s first breach involving patient data<\/a>. In 2019, about 11.9 million Quest patients were affected by a breach at AMCA, a third-party billing collections vendor. Medical records exposed in older breaches can still be misused today. Health data retains its value to criminals over time<\/a>, because unlike a credit card number, it cannot be canceled or reissued.<\/p>\n

Red Flags: Scams That Follow the Quest Breach<\/strong><\/h2>\n

The most immediate risk for most patients is follow-up scams that use the breach as a hook. Quest’s own notice warns people to watch for “breach-notification, credit-monitoring or settlement scams.”<\/p>\n\n\n\n\n\n\n\n\n\n
Red Flag<\/strong><\/td>\nWhy It Matters<\/strong><\/td>\n<\/tr>\n
An email, text, or call about the Quest breach asking you to confirm your Social Security number, insurance ID, or date of birth<\/strong><\/td>\nQuest has said it will notify affected patients by letter. A message asking you to re-enter personal data is a common way to collect more of it.<\/td>\n<\/tr>\n
A credit or identity monitoring offer that asks for payment or sends you to an unfamiliar link<\/strong><\/td>\nQuest says its notification letters will describe available resources, including credit and identity monitoring. Verify any offer through Quest’s official website or phone number.<\/td>\n<\/tr>\n
A “class action settlement” message asking for a fee or your bank details<\/strong><\/td>\nQuest’s notice specifically flags settlement scams. Treat any request to pay to join a settlement as fraud.<\/td>\n<\/tr>\n
A “your lab results are ready” message with a login link you didn’t expect<\/strong><\/td>\nScammers borrow the look of real health notices. Log in only through an app or website you already use.<\/td>\n<\/tr>\n
A bill or Explanation of Benefits (EOB) for lab tests or services you didn’t get<\/strong><\/td>\nCharges for care you never received can mean someone is using your medical identity.<\/td>\n<\/tr>\n
A debt collector contacting you about medical debt you don’t owe<\/strong><\/td>\nCollection notices for unfamiliar medical debt can mean someone received care or opened accounts in your name.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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How to Protect Yourself After the Quest Diagnostics Breach<\/strong><\/h2>\n

If you’ve had lab work processed by Quest, take these steps now, even if you don\u2019t yet know whether your records were involved.<\/p>\n

    \n
  1. Get updates from Quest directly.<\/strong> Use the official notice at questdiagnostics.com\/links\/quanum-notice<\/a> or call Quest at 1-866-MYQUEST. If someone contacts you first about the breach via call, text, or email, don\u2019t use any phone number or click any link they provide. Contact Quest through these official channels instead.<\/li>\n
  2. Watch your mail for a notification letter.<\/strong> Quest says it will send letters to affected patients once its investigation identifies them. If a letter includes a monitoring enrollment code, confirm it by contacting Quest through its official channels before you enroll.<\/li>\n
  3. Review your medical bills and EOBs.<\/strong> Look for tests, visits, or prescriptions you don’t recognize. This is one of the earliest places medical identity theft<\/a> shows up.<\/li>\n
  4. Check your credit reports.<\/strong> You can get free reports from Equifax, Experian, and TransUnion at AnnualCreditReport.com. Look for accounts or medical collections you don’t recognize.<\/li>\n
  5. Consider a credit freeze.<\/strong> A freeze is free and blocks new credit accounts from being opened in your name. You can lift it temporarily when you need to apply for credit.<\/li>\n
  6. Secure your health accounts.<\/strong> Use a unique password for any patient portal or health app, and turn on multi-factor authentication where it’s available. A password manager makes it easier to keep up with unique passwords.<\/li>\n
  7. Be skeptical of unexpected breach messages.<\/strong> Quest has said it will notify affected patients by letter. If an email, text, or call asks you to act quickly, click a link, or share personal or payment details, don’t respond. Contact Quest directly using the number on its official website.<\/li>\n<\/ol>\n

    What to Do If Your Information Was Exposed or You’ve Already Been Targeted<\/strong><\/h2>\n

    Your next steps depend on what has happened so far:<\/p>\n