Quest Diagnostics Inc. is investigating a data breach of its MyQuest by Care360 internet app which compromised the protected health information of about 34,000 individuals.

The company said information accessed during the Nov. 26 incident included details such as name, date of birth, lab results and phone numbers but did not include Social Security numbers, credit card information, insurance and other financial information.

Quest, which has notified affected customers, said it addressed the security vulnerability as soon as it was discovered. The company reported the event to law enforcement and enlisted a cybersecurity firm to further evaluate the company's systems.