Quest Diagnostics has taken a key laboratory management system offline after discovering unauthorized access to its network, the company disclosed this week. In a statement and accompanying FAQ, Quest said it believes some patient data within the affected system was accessed by the intruder.
The impacted platform, Quanum Lab Services Manager (LSM), is used by healthcare providers to place test orders and to receive and look up patient lab results. Quest paused access to the system while it investigates the incident and said several other systems were also temporarily paused as a precaution. The company stated that no other part of its operations has been affected.
Quest is working with law enforcement and is still determining what specific patient data was exposed. In the meantime, the company is directing customers to use paper requisitions in place of the online system and said it expects Quanum to be restored by Friday.
Quest specifically noted that the incident is unrelated to the recently disclosed PHP vulnerabilities that have drawn broad concern across the cybersecurity community. A company spokesperson declined to comment further on the nature of the attack, and no hacking group had claimed responsibility as of Thursday afternoon.
A pattern across healthcare testing firms
Quest is one of the largest clinical laboratory companies in the United States, reporting more than $11 billion in revenue last year. The New Jersey-based company says it serves roughly half of the doctors and hospitals in the country and tests about one in three American adults annually.
The incident adds to a growing list of cyberattacks against healthcare testing and records companies in 2026. Baylor Genetics recently disclosed a breach affecting more than 2.8 million patients, exposing lab results, medical testing information, and Social Security numbers. Several electronic health records vendors have also reported attacks this year.
In response to this wave of incidents, Congress passed legislation this month expanding federal cybersecurity requirements for healthcare organizations that handle patient data.
