LabCorp vs Quest Diagnostics: What Is the Difference?

When you order a lab test through Reliable Exams, you will visit either a LabCorp or Quest Diagnostics patient service center to have your blood drawn. Both are nationally recognized, CLIA-certified laboratory networks — but they are not identical.

Here is what you need to know about each one so you can choose the location that works best for you.

LabCorp (Laboratory Corporation of America) is one of the largest clinical laboratory networks in the world, processing more than 2.5 million tests per day. Founded in 1971 and headquartered in Burlington, North Carolina, LabCorp operates patient service centers across all 50 states.

Quest Diagnostics is LabCorp's closest competitor, processing approximately 550,000 tests per day across a nationwide network of patient service centers. Founded in 1967 and headquartered in Secaucus, New Jersey, Quest is also available in all 50 states.

Both companies are publicly traded, heavily regulated, and accredited by the College of American Pathologists (CAP) — one of the most rigorous laboratory accreditation standards in the world.

Both networks have extensive coverage across the United States, with thousands of patient service centers in most major cities and suburbs.

• LabCorp: approximately 2,000+ patient service centers nationwide
• Quest Diagnostics: approximately 2,200+ patient service centers nationwide

In practice, most people will find locations from both networks within a reasonable distance. The best way to find the closest option is to use our Find a Lab tool — enter your ZIP code and we will show you the nearest LabCorp and Quest locations on a map.

Tip: In some areas, one network will have significantly more locations than the other. It is worth checking both before deciding.

Both LabCorp and Quest Diagnostics accept walk-in patients at most locations, but both also offer online appointment scheduling.

LabCorp tends to have a smoother walk-in experience at many locations, with shorter average wait times reported by patients.

Quest Diagnostics also accepts walk-ins but strongly encourages scheduling an appointment online in advance, particularly at busier urban locations.

Our recommendation: Check the specific location's hours and reviews before visiting. A location with good reviews and online scheduling will almost always give you a faster, more pleasant experience than walking into a busy center without an appointment.

For most standard tests ordered through Reliable Exams, results are available within 1–2 business days regardless of whether your sample is processed by LabCorp or Quest.

Some specialized tests — such as certain genetic panels or complex hormone assays — may take longer at either lab. If turnaround time is critical for your situation, check the specific test's estimated timeframe before ordering.

Both labs offer a comprehensive menu of tests covering everything from basic blood panels to specialized diagnostics. For the tests available through Reliable Exams, both networks are fully capable of processing your order.

There are some niche or highly specialized tests that one lab may offer and the other may not — but for the 24 tests in our catalog, you will not notice a difference in availability.

Both LabCorp and Quest Diagnostics maintain rigorous quality control standards and are subject to federal oversight under the Clinical Laboratory Improvement Amendments (CLIA). Both hold CAP accreditation, which requires regular proficiency testing and on-site inspections.

In terms of accuracy and reliability for standard clinical tests, the two labs are essentially equivalent. Either one will give you results you can trust.

When you order through Reliable Exams, the price you pay is the same regardless of which lab network processes your test. You will not pay more or less based on whether you visit a LabCorp or Quest location.

If you were ordering directly through the labs without a service like Reliable Exams, pricing would vary significantly — and both labs are known for high out-of-pocket costs without insurance or a negotiated rate.

This is where the two networks differ most noticeably — and where individual location quality matters more than the brand.

LabCorp locations generally receive slightly higher patient satisfaction ratings on average, with patients citing shorter wait times and friendlier staff. However, this varies enormously by location.

Quest Diagnostics has invested heavily in its digital experience, with a well-regarded app and online portal for scheduling and results. Some patients prefer Quest for the convenience of managing everything digitally.

The honest answer: the quality of your experience will depend far more on the specific location you visit than on which brand it belongs to. Check Google reviews for the specific address before you go.

Here is a simple decision framework:

Use our Find a Lab tool to search by ZIP code, city, or state. We will show you the nearest LabCorp and Quest Diagnostics patient service centers on a map so you can compare distance, hours, and directions before you go.

Both networks are open Monday through Friday, with many locations offering Saturday morning hours. Hours vary by location, so always confirm before visiting.

LabCorp and Quest Diagnostics are both excellent, nationally accredited laboratory networks. For the vast majority of tests, the difference between them is minimal — what matters most is finding a convenient location with good hours and a solid local reputation.

When you order through Reliable Exams, your requisition form works at either network. Choose the one that is closest, most convenient, or has the best reviews in your area.

Find a lab near you and get your results in 1–2 business days.