Case file: Quest Diagnostics
Every government filing on this incident, the dates as stated, and the days to notice against each state's statute. Built from the records on Nov 9, 2026, agency link on every row. Not legal advice.
The incident
- Breach window
- Oct 29, 2021
- Discovered
- No discovery date stated in the letters we read
- State and federal records
- 1 filing, Nov 16, 2021
- Residents counted
- No state publishes a resident count for this incident
- Everyone affected
- No filing gives a total
- Information exposed
- Social Security number, Email address, Postal address
- Offered to those affected
- credit or identity monitoring through Experian (term not stated in the letter we read)
- Third party named
- No
- Prior incidents
- 2 earlier incidents on record for this organization
Filings
| Agency | Record date | People | In total | Days to notice | Links |
|---|---|---|---|---|---|
| California California AG | Nov 16, 2021 | Not published | 18 days from breach end, statute 30 days | Letter Record |
People is the count the filing gives, residents of the state unless marked total. Days to notice runs from the discovery date the letter states, or from the end of the breach window when no letter states one, to the date on the state's first record of the incident. "Over" marks a count past the days the state's statute allows for notice to residents. The statute's trigger is a question of fact, the days are arithmetic.
Notice timing, state by state
- 18 days from the end of the breach window (Oct 29, 2021, no discovery date in the letter) to the California record (Nov 16, 2021). Statute: 30 days from discovery or notification of the breach (Cal. Civ. Code § 1798.82).
The statutes
- California: 30 days to notify residents from discovery or notification of the breach, Cal. Civ. Code § 1798.82. Sample notice to the Attorney General when more than 500 Californians are notified, within 15 days of the consumer notice (effective 2026).
Prior incidents by Quest Diagnostics
| Records | Breach window | Filed with | People |
|---|---|---|---|
| Dec 12, 2016 | Nov 26, 2016 | Oregon, California | 34,055 total |
| Dec 19, 2014 | Nov 17, 2014 | California | n/a |
Filings more than six months apart are shown as separate incidents.
Filings by others that name Quest Diagnostics
Clients of a breached vendor often file under their own names and name the vendor.
- ExamOne (a Quest Diagnostics Company), Massachusetts, Oct 24, 2026, 1
- ExamOne (a Quest Diagnostics Company), Massachusetts, Aug 22, 2026, 1
- ExamOne (a Quest Diagnostics Company), Massachusetts, Aug 13, 2026, 1
- ExamOne (a Quest Diagnostics Company), Massachusetts, Aug 3, 2026, 1
- ExamOne (a Quest Diagnostics Company), Massachusetts, Jul 10, 2026, 1
- ExamOne (a Quest Diagnostics Company), Massachusetts, May 13, 2026, 1
Sources and method
Records as published by California AG. Letter facts (discovery date, monitoring, third party) are read from the consumer letter the agency posted, 1 letter read for this incident, and quoted so you can check them. Texas and HHS publish no letters. First-seen times on each record page. Spot an error? Email support@breachtally.com with this page link.