DGX vs GH: Which Is the Better Buy in 2026?
Last updated August 2026
Short answer
DGX (Quest Diagnostics) and GH (Guardant Health) share investment themes but are different businesses. The right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme.
DGX vs GH: the tie-breaker metrics
Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.
| Metric | DGX | GH | What it tells you |
|---|---|---|---|
| Market cap | $25.72B | $21.74B | Size. The larger name is the incumbent; the smaller has more room to grow and more to prove. |
| Forward P/E | 19.32 | -367.58 | Valuation on next year's expected earnings, the same yardstick for both. Lower is cheaper for that growth; higher means the market is paying up. |
| Beta | 0.57 | 1.59 | Volatility vs the market. Above 1 swings harder than the index; below 1 is steadier. Higher beta means bigger drawdowns to hold through. |
| Price vs 52-week range | 90% of range | 89% of range | Where today's price sits between the 52-week low and high. Near the high is momentum with less margin of safety; near the low is out of favor or a discount, depending on why. |
Before you buy: how DGX and GH affect your concentration
The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. DGX and GH share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.
This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined DGX and GH exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.
What does Quest Diagnostics (DGX) do?
Quest Diagnostics operates one of the largest clinical laboratory networks in the United States, processing billions of test results a year across a footprint of patient service centers, hospital and physician outreach relationships, and consumer-initiated testing. Its core Diagnostic Information Services segment spans routine testing (blood counts, cholesterol, metabolic panels) plus a growing base of advanced molecular and genomic diagnostics in oncology, neurology, women's health, and infectious disease. Scale, a national logistics network, and long-standing payer contracts are the company's main moats in a fragmented roughly $100 billion US lab market where Quest and Labcorp together hold the top tier.
What does Guardant Health (GH) do?
Guardant Health is a precision-oncology company that reads cancer signals from blood and tissue samples. Its business runs across three lines. Oncology, the largest, sells tests like Guardant360 (comprehensive genomic profiling that helps match patients to targeted therapies) and Guardant Reveal (a blood test for minimal residual disease, meaning traces of cancer left after treatment). Biopharma and Data sells testing, companion-diagnostic development, and real-world data to drugmakers. Screening is the newest and most-watched line: Shield is the first blood test to win full FDA approval as a primary screening option for colorectal cancer in average-risk adults 45 and older. In Q1 2026 the company reported ~$302 million in revenue, with oncology up 36% to ~$205 million on ~86,000 tests, biopharma and data at ~$53 million, and screening at ~$41.6 million on ~44,000 Shield tests (versus ~$5.7 million a year earlier).
DGX vs GH: how do they differ?
Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.
- DGX drivers: Organic volume growth; Acquisitions as a growth engine.
- GH drivers: Shield colorectal screening ramp; Core oncology growth and leverage.
Which fits which kind of investor
A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The largest risk is reimbursement policy: Medicare rates under PAMA face potential cuts (a delay pushed reductions toward 2027, but a roughly 15 percent cut to hundreds of tests looms without permanent reform), and private-payer pricing pressure caps growth. For GH, guardant is unprofitable and cash-consumptive, so it depends on the Shield launch converting into durable, reimbursed volume rather than one-off wins.
DGX or GH: which should you pick?
DGX vs GH: the full fundamentals
DGX. In Q1 2026 Quest reported revenue of about $2.9 billion (up 9.2 percent) and adjusted EPS of $2.50 (up 13.1 percent), and raised full-year guidance. The stock traded near $205 in mid-July 2026 at a forward P/E under 20, a moderate multiple below primary competitor Labcorp. The dividend has risen for 15 consecutive years, most recently a 7.5 percent increase.
GH. Figures are approximate and tied to the asOf date; verify live numbers before acting. GH trades on a high price-to-sales multiple typical of a fast-growing, pre-profit diagnostics company, so the valuation is driven by expected future growth rather than current earnings. The share price is volatile and moved sharply in mid-2026 on reimbursement news (including a July 2026 UnitedHealth coverage decision for Shield), which is why the timeline to 2027 cash-flow breakeven and the pace of Shield adoption matter more than any single quarter.
Headline figures (approximate, July 2026): DGX shows revenue (ttm) ~$11.5B, 2026 revenue guidance ~$11.78B to $11.9B, 2026 adj. eps guidance ~$10.63 to $10.83, market cap ~$22.8B; GH shows revenue (q1 2026 quarterly) ~$302 million, up 48% year over year, 2026 revenue guidance (full year) ~$1.30 to $1.32 billion (~32 to 34% growth), adjusted ebitda (q1 2026) ~-$59 million loss (still unprofitable), cash and equivalents ~$1.2 billion at quarter end.
The bottom line: DGX vs GH
DGX and GH are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined DGX and GH exposure against your real portfolio. It is not an investment adviser.
Wondering how DGX or GH fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in Quest Diagnostics with AI
Connect the broker you already use and ask Walnut's AI how DGX fits what you actually hold: whether you own it already through a fund, what it would do to your concentration, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What is the difference between DGX and GH?
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Quest Diagnostics operates one of the largest clinical laboratory networks in the United States, processing billions of test results a year across a footprint of patient service centers, hospital and physician outreach relationships, and consumer-initiated testing. Guardant Health is a precision-oncology company that reads cancer signals from blood and tissue samples. They show up together because they share investment themes, but they are different businesses, so the better fit depends on which thesis you are expressing.
Is DGX or GH the better stock?
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Neither is universally better; they suit different views and risk levels. Walnut is informational, not investment advice. Compare what each does, the tie-breaker metrics above, and the risks, then decide which fits your thesis and what you already own.
Which is cheaper, DGX or GH?
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On forward P/E (as of August 2026), DGX trades at 19.32x and GH at -367.58x, so GH is the cheaper of the two on next year's expected earnings. A lower multiple is not automatically the better buy: a richer valuation can be justified by faster growth, and a lower one can reflect real risk. Weigh the multiple against how fast each business is compounding.
Should you own both DGX and GH?
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Because they share themes, owning both concentrates you in that theme. That can be intentional (a focused bet) or accidental (less diversification than it looks). Walnut can show your combined exposure across both, and whether adding either over-concentrates you, before you buy.
What are the risks of DGX vs GH?
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DGX: The largest risk is reimbursement policy: Medicare rates under PAMA face potential cuts (a delay pushed reductions toward 2027, but a roughly 15 percent cut to hundreds of tests looms without permanent reform), and private-payer pricing pressure caps growth. Labor shortages in clinical lab technologists and molecular specialists can raise costs and constrain capacity. Increased FDA oversight of laboratory-developed tests could add compliance burden. Acquisition-led growth carries integration and overpayment risk, and a large debt load from deal activity adds interest expense. Finally, the business is competitive and partly commoditized, so share losses to Labcorp, hospital in-sourcing, or specialty labs would pressure both volume and margin. GH: Guardant is unprofitable and cash-consumptive, so it depends on the Shield launch converting into durable, reimbursed volume rather than one-off wins. Reimbursement is the central swing factor: coverage decisions, guideline inclusion, and per-test pricing (the $1,495 Medicare rate, private payer terms) can move sharply and are outside the company's control. Competition is intense from Exact Sciences (Cologuard in colorectal screening), Natera (minimal residual disease), and Roche's Foundation Medicine (genomic profiling), which pressures pricing and share. Shield's clinical sensitivity, roughly 84% overall but lower for early-stage and precancerous lesions, invites scrutiny versus colonoscopy. The stock also trades at a high price-to-sales multiple, so any slip in growth or the breakeven timeline can trigger large swings.
Walnut is informational, not investment advice. This page is descriptive and not a recommendation to buy or sell DGX or GH; figures are approximate and dated (as of August 2026). Verify current data before investing.