Quest Diagnostics vs Guardant Health: why the prices moved differently

Weekly · monthly · quarterly news summaries, side by side in time

Quest Diagnostics Incorporated (DGX)

Q3 202624 Jun – 8 Oct 2026

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Quest's strong Q3 met Medicare fee-cut risk

New tests and partnerships drive growth New York approved Quest's Haystack MRD cancer test in all 50 states, Attunio Health named Quest its national lab partner, and Q2 revenue rose 10.2% to $3.04B with raised 2026 guidance.
These new approvals and partnerships directly boosted Quest's business and investor confidence.
Medicare fee cuts threaten revenue CMS proposed cutting Medicare lab fees by up to 15% starting in 2027, which would directly hit Quest's roughly 11% of revenue from Medicare, creating a major overhang.
This regulatory risk could significantly reduce future profits and weighed on the stock.
New products and joint venture boost outlook Quest announced a $119 Apple Health app lab panel, plans an FDA-cleared Alzheimer's blood test, and expects its Corewell joint venture to add about $250M in 2026 revenue, with earnings estimates up 11.2% to $11.15 per share.
These initiatives expand Quest's offerings and revenue streams, supporting future growth.
Analysts split on valuation and margins Analysts raised their fair value estimate to $239.38, but UBS stayed Neutral on margin concerns, reflecting a balance between growth optimism and profitability worries.
This shows the market's mixed view on Quest's prospects, balancing positive growth with margin risks.

September 202619 Aug – 8 Oct 2026

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Medicare lab fee cuts hit Quest; new consumer and Alzheimer's tests offer growth

Medicare proposes up to 15% lab fee cuts CMS says Medicare overpays labs by 16% and proposes cutting lab fees up to 15% from 2027, saving taxpayers $1B a year. Quest gets about 11% of revenue from Medicare, so lower rates directly reduce its testing revenue and profit.
This is the main new force pushing DGX down this period.
Quest to sell lab tests through Apple Health app Quest will sell a $119 lab panel with over 50 biomarkers directly through Apple's Health app, with blood draws at its roughly 2,000 centers. This opens a new consumer sales channel, adding demand for tests outside doctor referrals.
A new growth channel that can lift future testing volume and revenue.
FDA clears Alzheimer's blood test Quest can offer The FDA cleared Roche and Lilly's Alzheimer's blood test, and Quest plans to offer it through its network. It is a simpler, cheaper alternative to PET scans, so it can bring more patients into Quest's labs for testing.
New test availability can increase demand for Quest's diagnostic services.
Corewell joint venture and rising profit estimates Quest's Corewell Health lab joint venture is expected to add about $250 million to 2026 revenue, and analysts raised their 2026 earnings estimate 11.2% to $11.15 a share. Physician and hospital testing volumes are growing, supporting the stock.
Shows underlying business growth and higher expected profits, a positive counterweight to the Medicare cut.

Latest19 Aug – 8 Oct 2026

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Medicare lab fee cuts hit Quest; new consumer and Alzheimer's tests offer growth

Medicare proposes up to 15% lab fee cuts CMS says Medicare overpays labs by 16% and proposes cutting lab fees up to 15% from 2027, saving taxpayers $1B a year. Quest gets about 11% of revenue from Medicare, so lower rates directly reduce its testing revenue and profit.
This is the main new force pushing DGX down this period.
Quest to sell lab tests through Apple Health app Quest will sell a $119 lab panel with over 50 biomarkers directly through Apple's Health app, with blood draws at its roughly 2,000 centers. This opens a new consumer sales channel, adding demand for tests outside doctor referrals.
A new growth channel that can lift future testing volume and revenue.
FDA clears Alzheimer's blood test Quest can offer The FDA cleared Roche and Lilly's Alzheimer's blood test, and Quest plans to offer it through its network. It is a simpler, cheaper alternative to PET scans, so it can bring more patients into Quest's labs for testing.
New test availability can increase demand for Quest's diagnostic services.
Corewell joint venture and rising profit estimates Quest's Corewell Health lab joint venture is expected to add about $250 million to 2026 revenue, and analysts raised their 2026 earnings estimate 11.2% to $11.15 a share. Physician and hospital testing volumes are growing, supporting the stock.
Shows underlying business growth and higher expected profits, a positive counterweight to the Medicare cut.

July 202624 Jun – 5 Aug 2026

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Quest raises 2026 outlook on strong Q2 and new test approval

New York approval opens Haystack MRD to all 50 states New York State approved Quest's Haystack MRD liquid biopsy test, making it available in all 50 states. This regulatory win expands the market for a high-value cancer test, supporting future revenue growth and lifting DGX shares.
This is a new regulatory milestone that directly expands Quest's addressable market for a premium test.
Attunio Health picks Quest as national lab backbone Attunio Health selected Quest as its national lab partner for precision psychiatry, with at-home blood collection via Getlabs. This adds new test volume from a growing mental health platform, a modest but positive demand driver for DGX.
A new partnership that adds incremental testing volume and shows Quest winning new business.
Q2 beat and raised 2026 guidance boost outlook Quest reported Q2 revenue up 10.2% to $3.04B and adjusted EPS of $3.12, beating estimates, and raised full-year 2026 revenue and EPS guidance. Strong organic growth and a tax benefit drove the increase, signaling momentum.
The guidance raise and earnings beat are the core fundamental drivers of the stock's recent move.
Analysts raise fair value and price targets after Q2 Analysts lifted Quest's fair value estimate to $239.38 from $223.44, with price targets mostly $245–$265. The upgrades reflect the earnings beat and higher guidance, though UBS stayed Neutral on margin concerns, a mild counterweight.
Analyst upgrades following the earnings beat reinforce the positive sentiment and help explain the stock's rise.

24 Jun – 5 Aug 2026

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Quest raises 2026 outlook on strong Q2 and new test approval

New York approval opens Haystack MRD to all 50 states New York State approved Quest's Haystack MRD liquid biopsy test, making it available in all 50 states. This regulatory win expands the market for a high-value cancer test, supporting future revenue growth and lifting DGX shares.
This is a new regulatory milestone that directly expands Quest's addressable market for a premium test.
Attunio Health picks Quest as national lab backbone Attunio Health selected Quest as its national lab partner for precision psychiatry, with at-home blood collection via Getlabs. This adds new test volume from a growing mental health platform, a modest but positive demand driver for DGX.
A new partnership that adds incremental testing volume and shows Quest winning new business.
Q2 beat and raised 2026 guidance boost outlook Quest reported Q2 revenue up 10.2% to $3.04B and adjusted EPS of $3.12, beating estimates, and raised full-year 2026 revenue and EPS guidance. Strong organic growth and a tax benefit drove the increase, signaling momentum.
The guidance raise and earnings beat are the core fundamental drivers of the stock's recent move.
Analysts raise fair value and price targets after Q2 Analysts lifted Quest's fair value estimate to $239.38 from $223.44, with price targets mostly $245–$265. The upgrades reflect the earnings beat and higher guidance, though UBS stayed Neutral on margin concerns, a mild counterweight.
Analyst upgrades following the earnings beat reinforce the positive sentiment and help explain the stock's rise.

Guardant Health Inc (GH)

Q3 202624 Jun – 8 Oct 2026

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Guardant Health Q3 2026: Insurance Win, Strong Revenue, But Competition and Patent Costs Loom

UnitedHealth Coverage for Shield Test UnitedHealth became the first major insurer to cover Guardant's Shield colorectal cancer blood test, expanding access to over 100 million people. This should boost test volumes and revenue as more patients can afford the test.
This is a major new commercial milestone that directly expands the addressable market for a key product.
Strong Q2 Revenue and Raised Guidance Q2 revenue rose 44% to $335 million, beating estimates, and full-year guidance was lifted to $1.34–1.36 billion. This shows accelerating growth and management confidence in the business.
Financial results and guidance are core drivers of investor sentiment and stock price.
FDA and Europe Approve Guardant360 CDx for AstraZeneca Drug The FDA and Europe approved Guardant360 CDx for monitoring AstraZeneca's breast cancer drug, adding repeat-use revenue. This expands the test's clinical utility and creates a recurring revenue stream.
Regulatory approvals open new markets and support long-term revenue growth.
Quest Launches Haystack MRD Nationwide and Patent Ruling Upheld Quest's Haystack MRD test launched nationwide, intensifying competition and potentially pressuring pricing and market share. A court also upheld a $245.2 million patent-infringement ruling plus a 6% royalty on certain sales through 2033, a real cash cost.
These are significant headwinds that could limit growth and profitability, weighing on the stock.

September 202617 Aug – 8 Oct 2026

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Guardant's test approvals expand, but patent ruling adds a cost

FDA clears Guardant360 for breast cancer monitoring The FDA approved Guardant360 CDx as a companion test for AstraZeneca's new breast cancer drug Etcamah. This lets doctors use a simple blood draw every three months to catch treatment resistance early. It adds a new, repeat-use market for Guardant's flagship test, supporting revenue growth.
This is a new regulatory approval that directly expands the market for Guardant's core product.
European approval extends the same breast cancer test Guardant360 CDx received CE-marking in Europe for the same Etcamah companion use. This opens the test to European patients and marks Guardant's 31st companion diagnostic approval. It broadens the addressable market beyond the U.S. and Japan, adding another long-term revenue stream.
This is a new geographic expansion of the same test, increasing the potential patient pool.
Court orders $245 million patent payment A U.S. court upheld a jury verdict that Guardant infringed DNA sequencing patents, ordering $245.2 million in damages and royalties, plus a continuing 6% royalty on certain sales until 2033. Guardant plans to appeal. This is a real cash cost and a drag on future profits, though the appeal could reduce it.
This is a new legal ruling with a concrete financial impact that weighs on earnings and sentiment.
Strong revenue growth beats peers Guardant reported quarterly revenue of $335 million, up 44.3% from a year earlier, beating analyst estimates by 6.4% — the biggest beat and fastest growth among testing and diagnostics peers. It also raised full-year guidance the most. This shows the business is scaling quickly and winning share.
This is new financial data showing accelerating demand and execution, a core driver of the stock's value.

Latest17 Aug – 8 Oct 2026

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Guardant's test approvals expand, but patent ruling adds a cost

FDA clears Guardant360 for breast cancer monitoring The FDA approved Guardant360 CDx as a companion test for AstraZeneca's new breast cancer drug Etcamah. This lets doctors use a simple blood draw every three months to catch treatment resistance early. It adds a new, repeat-use market for Guardant's flagship test, supporting revenue growth.
This is a new regulatory approval that directly expands the market for Guardant's core product.
European approval extends the same breast cancer test Guardant360 CDx received CE-marking in Europe for the same Etcamah companion use. This opens the test to European patients and marks Guardant's 31st companion diagnostic approval. It broadens the addressable market beyond the U.S. and Japan, adding another long-term revenue stream.
This is a new geographic expansion of the same test, increasing the potential patient pool.
Court orders $245 million patent payment A U.S. court upheld a jury verdict that Guardant infringed DNA sequencing patents, ordering $245.2 million in damages and royalties, plus a continuing 6% royalty on certain sales until 2033. Guardant plans to appeal. This is a real cash cost and a drag on future profits, though the appeal could reduce it.
This is a new legal ruling with a concrete financial impact that weighs on earnings and sentiment.
Strong revenue growth beats peers Guardant reported quarterly revenue of $335 million, up 44.3% from a year earlier, beating analyst estimates by 6.4% — the biggest beat and fastest growth among testing and diagnostics peers. It also raised full-year guidance the most. This shows the business is scaling quickly and winning share.
This is new financial data showing accelerating demand and execution, a core driver of the stock's value.

July 202624 Jun – 30 Jul 2026

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Guardant's Shield Wins Insurance Coverage and Sales Surge, Lifting Guidance

UnitedHealth covers Shield blood test UnitedHealth, America's largest commercial insurer, became the first big insurer to cover Guardant's Shield blood test for colorectal cancer screening. Over 100 million people can now get it. More covered patients means more test sales, pushing revenue and the stock up.
This is a major new demand catalyst that directly expands the market for Guardant's key screening product.
Q2 revenue jumps 44%, guidance raised Guardant reported second-quarter revenue of $335 million, up 44% from a year ago, and raised its full-year 2026 revenue outlook to $1.34–$1.36 billion. Oncology test volume grew 63% and Shield screening revenue more than tripled. Strong growth signals the business is scaling, which supports a higher stock price.
This is the latest hard financial evidence of accelerating demand and management confidence, a core driver of the stock.
Quest's Haystack MRD test goes nationwide Quest Diagnostics won New York approval for its Haystack MRD liquid biopsy test, clearing it for use in all 50 states. This puts a large, well-funded competitor directly into cancer monitoring, where Guardant also plays. More competition could pressure Guardant's pricing and market share, a real counterweight.
It is a new competitive threat that could limit Guardant's growth in the cancer-monitoring market.

24 Jun – 30 Jul 2026

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Guardant's Shield Wins Insurance Coverage and Sales Surge, Lifting Guidance

UnitedHealth covers Shield blood test UnitedHealth, America's largest commercial insurer, became the first big insurer to cover Guardant's Shield blood test for colorectal cancer screening. Over 100 million people can now get it. More covered patients means more test sales, pushing revenue and the stock up.
This is a major new demand catalyst that directly expands the market for Guardant's key screening product.
Q2 revenue jumps 44%, guidance raised Guardant reported second-quarter revenue of $335 million, up 44% from a year ago, and raised its full-year 2026 revenue outlook to $1.34–$1.36 billion. Oncology test volume grew 63% and Shield screening revenue more than tripled. Strong growth signals the business is scaling, which supports a higher stock price.
This is the latest hard financial evidence of accelerating demand and management confidence, a core driver of the stock.
Quest's Haystack MRD test goes nationwide Quest Diagnostics won New York approval for its Haystack MRD liquid biopsy test, clearing it for use in all 50 states. This puts a large, well-funded competitor directly into cancer monitoring, where Guardant also plays. More competition could pressure Guardant's pricing and market share, a real counterweight.
It is a new competitive threat that could limit Guardant's growth in the cancer-monitoring market.