Quest Diagnostics (DGX) stock has been in focus after the company reported second quarter and six month 2026 results and raised its full year revenue and earnings guidance, indicating that the company now expects higher financial performance.

Quest Diagnostics shares have picked up pace over 2026, with a 1‑month share price return of 8.34%, a 90‑day gain of 23.58%, and a 1‑year total shareholder return of 37.26%. This reflects recent share price momentum following upgraded guidance, ongoing buybacks and new service launches.

If the recent guidance upgrade caught your attention, this can be a good time to widen your watchlist with healthcare focused AI opportunities such as those in the 41 healthcare AI stocks

After a 37.26% 1 year total return and fresh guidance from Quest Diagnostics, the debate now turns to price. Is most of the upside already reflected in the stock, or does today’s valuation still leave meaningful headroom?

Most Popular Narrative: 2.4% Undervalued

Quest Diagnostics last closed at $233.72, compared with a narrative fair value estimate of $239.38. That small gap is where the current debate starts.

The rising importance of health data analytics and Quest's role as a "lab engine" for consumer wellness brands positions the company to benefit from new revenue streams and further monetization opportunities as healthcare becomes more data-driven, supporting long-term earnings power.

Curious what sits behind that fair value for Quest Diagnostics. The narrative leans on steady revenue expansion, higher margins and a future earnings multiple that must hold up under closer scrutiny.

Result: Fair Value of $239.38 (UNDERVALUED)

However, Quest Diagnostics investors still need to watch for reimbursement cuts and higher wage and automation costs that could squeeze margins and challenge the current fair value story.

Next Steps

With both risks and rewards in play for Quest Diagnostics, this is a moment to move quickly, review the data yourself and weigh both sides. To see a concise summary of the trade off between potential upside and key concerns, check out the 4 key rewards and 1 important warning sign.

Looking for more investment ideas beyond Quest Diagnostics?

Do not stop at Quest Diagnostics. Use this moment to scan a wider field of opportunities so your portfolio does not miss out on other compelling setups.

• Target dependable income by reviewing companies with resilient payouts through the 7 dividend fortresses.
• Spot potential value opportunities early by filtering for companies trading below their estimated worth using the 52 high quality undervalued stocks.
• Prioritise capital preservation by focusing on companies that score well on stability and risk using the 82 resilient stocks with low risk scores.

This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.