Neither Quest Diagnostics nor Labcorp is categorically better. Both are massive, federally certified clinical laboratories that process billions of tests per year with high accuracy. The real answer depends on your insurance network, how close a location is to you, and whether you need a specific type of test. Here’s how they actually compare on the things that matter.
Insurance Is the Biggest Factor
Your insurance plan likely has a preferred lab network, and using the wrong one can turn a $0 blood draw into a surprise bill of several hundred dollars. This single factor matters more than anything else in the Quest vs. Labcorp debate.
Quest Diagnostics is the preferred lab for UnitedHealthcare members, meaning those members typically pay low or zero out-of-pocket costs. Quest also partners with Aetna, Humana, Cigna, and most Anthem and BlueCross BlueShield plans. Labcorp has similarly broad insurance relationships and is the preferred lab for many plans that don’t default to Quest. Some insurers contract with both but designate one as “preferred” and the other as “in-network, non-preferred,” which can still mean a higher copay.
Before you choose a lab, call the number on the back of your insurance card or check your plan’s provider directory online. Search specifically for the words “preferred lab” rather than just “in-network.” That distinction alone can save you more money than any difference in test quality or convenience.
Location and Convenience
Quest operates around 2,200 patient service centers across the United States. Labcorp runs a similar number. In most metro areas, you’ll find both within a reasonable drive, but in smaller towns or rural areas, one may have a location and the other may not. Proximity matters when you’re fasting for a morning blood draw or need to get in and out during a lunch break.
Both companies have expanded into retail locations. Quest has patient service centers inside Albertsons-owned grocery stores (including Safeway, Randalls, Tom Thumb, and Vons) across multiple states, and has partnered with Walmart for in-store testing at select locations in Florida and Texas. Labcorp has partnered with Walgreens to open blood-testing sites inside hundreds of drugstore locations. These retail sites can be more convenient than standalone labs, with extended hours and walk-in availability. Check both companies’ websites to see which has a draw site closest to your home or workplace.
Results Speed and Patient Portals
For routine blood work like a metabolic panel or lipid panel, both labs deliver results in a similar window. Quest states that most test results are available within 2 to 5 days of collection, though complex or specialized tests can take 14 days or longer. Labcorp operates on a comparable timeline for standard panels. In practice, many routine results from either lab show up within 1 to 3 business days.
Both companies offer free patient apps. Quest’s MyQuest app and Labcorp’s Patient app let you view results as soon as they’re released, check historical lab work, find nearby locations, and schedule appointments. Labcorp’s app also lets you check in before you arrive and receive a QR code for faster processing at the front desk. Quest offers similar pre-visit features. The apps are functionally comparable, and neither is a meaningful reason to choose one lab over the other.
Specialized and Genetic Testing
Where the two labs start to differ is in niche and specialty testing. Both offer standard panels that any primary care doctor would order, and the results are equally reliable. But each company has acquired specialized subsidiaries over the years that give them strengths in different areas.
Quest expanded into genetic testing through its acquisition of Blueprint Genetics, which provides specialized panels for hereditary cancer risk, cardiovascular conditions, and other inherited diseases. Quest also owns Athena Diagnostics, which focuses on neurological testing. Labcorp, through its drug development division (formerly Covance) and subsidiaries like Monogram Biosciences, has deep capabilities in infectious disease resistance testing and pharmaceutical trial support.
For most people getting routine lab work ordered by a primary care doctor, these specialty divisions are irrelevant. But if your doctor orders a specific proprietary test, it may only be available through one lab. In that case, your doctor’s office will typically send you to the right one automatically.
Test Quality and Accreditation
Both labs meet the same federal standards. All Quest Diagnostics testing locations are certified under the Clinical Laboratory Improvement Amendments (CLIA), the federal program that regulates lab quality. Quest’s regional and esoteric reference laboratories also hold accreditation from the College of American Pathologists (CAP), which is considered the gold standard in laboratory oversight. Labcorp maintains the same CLIA certification and CAP accreditation across its major facilities.
In terms of actual test accuracy, there is no meaningful difference for routine blood work. Both labs use the same types of analyzers, follow the same quality control protocols, and participate in the same proficiency testing programs. Occasional errors happen at any lab, but neither company has a systemic accuracy advantage over the other.
How to Choose
Start with your insurance. If your plan has a preferred lab, use it. If both labs are equally covered, pick the one that’s closer to you or has more convenient hours. If you need a specific specialized test, your doctor will guide you to the right lab. For everything else, the two companies are functionally interchangeable. The quality of your results will be the same.