Top billers · Clinical Laboratories · California

What are the biggest clinical labs in California?

In 2024, 322 clinical laboratories billed Medicare for laboratory testing in California: 38,614,721 services and an estimated $1.6B in Medicare payments. Below: the top 5 by service volume, straight from CMS's public billing data.

322
Clinical labs billing Medicare (2024)
38.6M
Services billed
$1.6B
Est. Medicare paid
↓ 4%
Providers vs 2023
The list

The top 5 clinical laboratories in California.

Ranked by 2024 Medicare service volume across the family's codes.

#ProviderSpecialtyCityServicesEst. Medicare paid
1Unilab CorporationClinical LaboratoryWest Hills7,761,695$95.8M
2Laboratory Corporation Of AmericaClinical LaboratorySan Diego5,873,896$66.7M
3Unilab CorporationClinical LaboratorySacramento3,912,577$47.4M
4Myonsite Diagnostic LabClinical LaboratoryRancho Santa Margarita1,506,998$1.7M
5Scripps HealthClinical LaboratorySan Diego864,161$10.5M

That's the top 5. 317 more clinical laboratories billed laboratory testing in California in 2024. The full ranked list, with year-over-year history, group affiliations, and phone numbers, is one search in Prospect 811.

See the full list
The breakdown

What's behind the number.

Top codes in California

80053Blood test, comprehensive group of blood chemicals2,517,904
85025Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count2,234,338
87798Detection test by nucleic acid for organism, amplified probe technique2,045,220
80061Blood test, lipids (cholesterol and triglycerides)1,722,480
83036Hemoglobin a1c level1,359,165
84443Blood test, thyroid stimulating hormone (tsh)1,356,861

Top specialties billing it

Clinical Laboratory322 providers

Where the laboratories are

San Diego33 providers
Irvine15 providers
Los Angeles14 providers
North Hollywood11 providers
Burbank10 providers
City breakdown

The top laboratory testing cities in California.

The same 2024 Medicare data, sliced by city: the biggest laboratory testing cities by number of laboratories, in est.-Medicare-paid order.

In 2024 the top city for laboratory testing in California by est. Medicare paid was San Diego: 33 clinical laboratories billed 7,377,191 services for an estimated $265.2M, led by Laboratory Corporation Of America, with 5,873,896 services (est. $66.7M Medicare paid).

#CityLaboratoriesServicesEst. Medicare paidCity leader (2024)
1San Diego337,377,191$265.2MLaboratory Corporation Of America · 5,873,896 services · est. $66.7M
2Irvine15893,400$56.0MInternational Medical Laboratory · 626,643 services · est. $5.9M
3North Hollywood11706,454$24.3MLifeline Medical Laboratory Incorporated · 101,480 services · est. $5.0M
4Burbank101,263,043$20.7MNbio Lab Inc · 319,921 services · est. $6.2M
5Los Angeles14611,885$11.5MAbacus Business Corporation Group Inc. · 514,893 services · est. $5.1M

City totals are cut from the same public CMS data as everything above: Medicare fee-for-service only, after CMS's under-11-beneficiary suppression, dollars always est. Medicare paid. Where a city shows fewer than 3 laboratories, we show the totals and name no one. Naming is capped by design: up to 5 ranked laboratories above plus at most one leader per city here, and no one else on this page.

Where these numbers come from. Everything on this page is computed from CMS's public Medicare Provider Utilization & Payment data for 2024, the most recent year CMS has released. It covers traditional Medicare fee-for-service only (no commercial insurance, no Medicare Advantage). CMS suppresses any provider-and-code line with fewer than 11 beneficiaries before publishing, so low-volume billers don't appear at all. "Est. Medicare paid" is each billing line's average Medicare payment multiplied by its service count, summed. One service is one billed test or service line as CMS reports it. Prospect 811 organizes public data; it doesn't add to or alter it. Not affiliated with or endorsed by CMS. Full detail on the data page.

This is one code family, one state, one year.

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