Investors interested in stocks from the Medical - Dental Supplies sector have probably already heard of LabCorp (LH) and Conmed (CNMD). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, LabCorp has a Zacks Rank of #2 (Buy), while Conmed has a Zacks Rank of #3 (Hold). This means that LH's earnings estimate revision activity has been more impressive, so investors should feel comfortable with its improving analyst outlook. But this is just one factor that value investors are interested in.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its current share price levels.Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.LH currently has a forward P/E ratio of 12.10, while CNMD has a forward P/E of 40.69. We also note that LH has a PEG ratio of 1.15. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. CNMD currently has a PEG ratio of 4.10.Another notable valuation metric for LH is its P/B ratio of 2.70. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, CNMD has a P/B of 5.15.These metrics, and several others, help LH earn a Value grade of A, while CNMD has been given a Value grade of C.LH sticks out from CNMD in both our Zacks Rank and Style Scores models, so value investors will likely feel that LH is the better option right now. More Stock News: This Is Bigger than the iPhone! It could become the mother of all technological revolutions. Apple sold a mere 1 billion iPhones in 10 years but a new breakthrough is expected to generate more than 77 billion devices by 2025, creating a $1.3 trillion market. Zacks has just released a Special Report that spotlights this fast-emerging phenomenon and 4 tickers for taking advantage of it. If you don't buy now, you may kick yourself in 2022.Click here for the 4 trades >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Laboratory Corporation of America Holdings (LH): Free Stock Analysis Report CONMED Corporation (CNMD): Free Stock Analysis Report To read this article on Zacks.com click here.