DexCom (DXCM) could be a solid choice for investors given the company's remarkably improving earnings outlook. While the stock has been a strong performer lately, this trend might continue since analysts are still raising their earnings estimates for the company.The rising trend in estimate revisions, which is a result of growing analyst optimism on the earnings prospects of this medical device company, should get reflected in its stock price. After all, empirical research shows a strong correlation between trends in earnings estimate revisions and near-term stock price movements. This insight is at the core of our stock rating tool -- the Zacks Rank.The five-grade Zacks Rank system, which ranges from a Zacks Rank #1 (Strong Buy) to a Zacks Rank #5 (Strong Sell), has an impressive externally-audited track record of outperformance, with Zacks #1 Ranked stocks generating an average annual return of +25% since 2008.Consensus earnings estimates for the next quarter and full year have moved considerably higher for DexCom, as there has been strong agreement among the covering analysts in raising estimates.The chart below shows the evolution of forward 12-month Zacks Consensus EPS estimate:12 Month EPSCurrent-Quarter Estimate RevisionsThe earnings estimate of $0.72.72 per share for the current quarter represents a change of +33.33% from the number reported a year ago.Over the last 30 days, five estimates have moved higher for DexCom while two have gone lower. As a result, the Zacks Consensus Estimate has increased 5.68%.Current-Year Estimate RevisionsThe company is expected to earn .43 per share for the full year, which represents a change of +376.67% from the prior-year number.There has been an encouraging trend in estimate revisions for the current year as well. Over the past month, nine estimates have moved up for DexCom versus no negative revisions. This has pushed the consensus estimate 51.83% higher.Favorable Zacks RankThe promising estimate revisions have helped DexCom earn a Zacks Rank #1 (Strong Buy). The Zacks Rank is a tried-and-tested rating tool that helps investors effectively harness the power of earnings estimate revisions and make the right investment decision. You can see the complete list of today's Zacks #1 Rank (Strong Buy) stocks here.Our research shows that stocks with Zacks Rank #1 (Strong Buy) and 2 (Buy) significantly outperform the S&P 500.Bottom LineDexCom shares have added 44.2% over the past four weeks, suggesting that investors are betting on its impressive estimate revisions. So, you may consider adding it to your portfolio right away to benefit from its earnings growth prospects.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 DexCom, Inc. (DXCM): Free Stock Analysis Report To read this article on Zacks.com click here.