Quest Diagnostics Inc vs GUARDANT HEALTH, INC., two Medical Diagnostics stocks. A side-by-side on valuation, growth, margins, returns, and what each price is betting.
Quest is diagnostics as a utility: routine tests at national scale, a 13.8% operating margin, a 5.6% free-cash yield, a dividend, and almost no debt. Guardant is diagnostics as a moonshot: blood-based cancer screening funded by a negative 40.2% operating margin and a drawn-down 4.7 current ratio. The market values the moonshot at $20B, within a rounding of the utility's $23B, which is the boldest sentence on either page: a loss-making test developer priced at par with the industry's steadiest cash machine. Quest trades at 23.2 times earnings; Guardant has none to price. The pair distills the sector's bet: that early cancer detection is worth one whole Quest before it earns a dollar.
Comparison updated 2026-07-10.
| Metric | DGX | GH |
|---|---|---|
| Price | $227.80 | $147.44 |
| Market cap | $25.5B | $19.4B |
| Sector | Medical Diagnostics | Medical Diagnostics |
| Stage | Mature | Growth |
| Implied growth (priced in) | -0.1% | — |
| P/E | 24.2 | — |
| P/B | 3.26 | — |
| P/S | 2.21 | 17.92 |
| EV/EBITDA | 13.8 | — |
| Revenue growth | +9.9% | +39.3% |
| Operating margin | 15.1% | -40.2% |
| Net margin | 9.2% | -40.1% |
| Return on equity | 13.6% | — |
| Return on assets | 6.3% | -22.6% |
| Return on invested capital | 9.6% | -26.7% |
| FCF yield | 5.3% | -1.2% |
| Dividend yield | 0.8% | — |
| Debt / equity | 0.72 | — |
| Current ratio | 1.59 | 4.68 |
| Altman Z (solvency) | 7.70 | 4.30 |
| Piotroski F (quality) | 7 / 9 | 3 / 9 |
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The stronger value is highlighted per metric where one is strictly better on that single number; it is not an overall verdict on either company. For informational and research purposes only. Not investment advice. Not a recommendation to buy, sell, or hold any security. boothcheck is not a registered investment adviser. Past performance does not guarantee future results.