Exhibit 22.1
Subsidiary Guarantors of Securities
As of July 25, 2022, the following subsidiaries of Quest Diagnostics Incorporated provided, subject to the terms of such senior notes, unconditional and irrevocable guarantees to the senior notes listed below that were issued by Quest Diagnostics Incorporated pursuant to an offering registered under the Securities Act of 1933, as amended:
| Securities | Issuer | Subsidiary Guarantor | State of Organization |
6.95% Senior Notes due 2037 5.75% Senior Notes due 2040 | Quest Diagnostics Incorporated | American Medical Laboratories, Incorporated | Delaware |
| AmeriPath, Inc. | Delaware |
| AmeriPath Consolidated Labs, Inc. | Florida |
| AmeriPath Florida, LLC | Delaware |
| AmeriPath Hospital Services Florida, LLC | Delaware |
| AmeriPath Kentucky, Inc. | Kentucky |
| AmeriPath New York, LLC | Delaware |
| AmeriPath Texas, Inc. | Delaware |
| Athena Diagnostics, Inc. | Delaware |
| Diagnostic Pathology Services, Inc. | Oklahoma |
| ExamOne World Wide, Inc. | Pennsylvania |
| ExamOne World Wide of NJ, Inc. | New Jersey |
| Kailash B. Sharma, M.D., Inc. | Georgia |
| LabOne, LLC | Missouri |
| LabOne of Ohio, Inc. | Delaware |
| Ocmulgee Medical Pathology Association, Inc. | Georgia |
| Quest Diagnostics Clinical Laboratories, Inc. | Delaware |
| Quest Diagnostics Holdings Incorporated | Delaware |
| Quest Diagnostics Incorporated | Maryland |
| Quest Diagnostics Incorporated | Nevada |
| Quest Diagnostics Investments LLC | Delaware |
| Quest Diagnostics LLC | Connecticut |
| Quest Diagnostics LLC | Illinois |
| Quest Diagnostics LLC | Massachusetts |
| Quest Diagnostics Nichols Institute | California |
| Quest Diagnostics Nichols Institute, Inc. | Virginia |
| Quest Diagnostics of Pennsylvania Inc. | Delaware |
| Specialty Laboratories, Inc. | California |
| Unilab Corporation | Delaware |
